[RFC][PATCHSET] reduce messing with iovecs in cifs

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[RFC][PATCHSET] reduce messing with iovecs in cifs

Al Viro-3
        Now that sendmsg/recvmsg do not mangle iovecs and are capable of
handling bvec-based ->msg_iter, we can seriously reduce the amount of PITA
in cifs.  The series below is completely untested, and I would appreciate
comments/review/testing/etc.

I'll post the individual patches in followups; for those who prefer to use
git it can be found in
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git sendmsg.cifs

1/6: [net] drop 'size' argument of sock_recvmsg()
        should go via net-next; does what it says.

2/6: cifs: merge the hash calculation helpers
        takes the common parts of {cifs,smb2,smb3}_calc_signature() into a
common helper.

3/6: cifs: quit playing games with draining iovecs
        Switch smb_send_kvec() to passing msghdr (and thus iov_iter) and
make it use sock_sendmsg() - that allows to avoid draining iovecs, since
->msg_iter will be advanced properly and all we need is to keep it around
between the calls of sock_sendmsg(), rather than reinitializing it on each
loop iteration.  The same thing allows to get rid of messing with kmap()
when sending the stuff in ->rq_pages[] - ITER_BVEC will do the right thing.

4/6: cifs: no need to wank with copying and advancing iovec on recvmsg side either
        Similar to the previous - use sock_recvmsg() in cifs_readv_from_socket()
and there's no need to modify iovecs, or allocate a copy especially for
such modifications, etc.

5/6: cifs_readv_receive: use cifs_read_from_socket()
        building a 1-element iovec array for cifs_readv_from_socket() is
an overkill - simple cifs_read_from_socket() will do just fine.

6/6: cifs: don't bother with kmap on read_pages side
        Similar to the other half of 3/6: we can use ITER_BVEC for
read-into-page case.  Just make cifs_readv_from_socket() take msghdr from
caller and use a helper that would feed it a bvec-backed ->msg_iter.
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[PATCH 1/6] [net] drop 'size' argument of sock_recvmsg()

Al Viro-3
all callers have it equal to msg_data_left(msg).

Signed-off-by: Al Viro <[hidden email]>
---
 drivers/target/iscsi/iscsi_target_util.c |  5 ++---
 include/linux/net.h                      |  3 +--
 net/socket.c                             | 23 ++++++++++-------------
 3 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 428b0d9..5772038 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -1283,9 +1283,8 @@ static int iscsit_do_rx_data(
  iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC,
       count->iov, count->iov_count, data);
 
- while (total_rx < data) {
- rx_loop = sock_recvmsg(conn->sock, &msg,
-      (data - total_rx), MSG_WAITALL);
+ while (msg_data_left(&msg)) {
+ rx_loop = sock_recvmsg(conn->sock, &msg, MSG_WAITALL);
  if (rx_loop <= 0) {
  pr_debug("rx_loop: %d total_rx: %d\n",
  rx_loop, total_rx);
diff --git a/include/linux/net.h b/include/linux/net.h
index 49175e4..72c1e06 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -218,8 +218,7 @@ int sock_create_lite(int family, int type, int proto, struct socket **res);
 struct socket *sock_alloc(void);
 void sock_release(struct socket *sock);
 int sock_sendmsg(struct socket *sock, struct msghdr *msg);
-int sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
- int flags);
+int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags);
 struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname);
 struct socket *sockfd_lookup(int fd, int *err);
 struct socket *sock_from_file(struct file *file, int *err);
diff --git a/net/socket.c b/net/socket.c
index 5f77a8e..956426e3 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -709,17 +709,16 @@ void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
 EXPORT_SYMBOL_GPL(__sock_recv_ts_and_drops);
 
 static inline int sock_recvmsg_nosec(struct socket *sock, struct msghdr *msg,
-     size_t size, int flags)
+     int flags)
 {
- return sock->ops->recvmsg(sock, msg, size, flags);
+ return sock->ops->recvmsg(sock, msg, msg_data_left(msg), flags);
 }
 
-int sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
- int flags)
+int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags)
 {
- int err = security_socket_recvmsg(sock, msg, size, flags);
+ int err = security_socket_recvmsg(sock, msg, msg_data_left(msg), flags);
 
- return err ?: sock_recvmsg_nosec(sock, msg, size, flags);
+ return err ?: sock_recvmsg_nosec(sock, msg, flags);
 }
 EXPORT_SYMBOL(sock_recvmsg);
 
@@ -746,7 +745,7 @@ int kernel_recvmsg(struct socket *sock, struct msghdr *msg,
 
  iov_iter_kvec(&msg->msg_iter, READ | ITER_KVEC, vec, num, size);
  set_fs(KERNEL_DS);
- result = sock_recvmsg(sock, msg, size, flags);
+ result = sock_recvmsg(sock, msg, flags);
  set_fs(oldfs);
  return result;
 }
@@ -796,7 +795,7 @@ static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to)
  if (!iov_iter_count(to)) /* Match SYS5 behaviour */
  return 0;
 
- res = sock_recvmsg(sock, &msg, iov_iter_count(to), msg.msg_flags);
+ res = sock_recvmsg(sock, &msg, msg.msg_flags);
  *to = msg.msg_iter;
  return res;
 }
@@ -1696,7 +1695,7 @@ SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size,
  msg.msg_iocb = NULL;
  if (sock->file->f_flags & O_NONBLOCK)
  flags |= MSG_DONTWAIT;
- err = sock_recvmsg(sock, &msg, iov_iter_count(&msg.msg_iter), flags);
+ err = sock_recvmsg(sock, &msg, flags);
 
  if (err >= 0 && addr != NULL) {
  err2 = move_addr_to_user(&address,
@@ -2073,7 +2072,7 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
  struct iovec iovstack[UIO_FASTIOV];
  struct iovec *iov = iovstack;
  unsigned long cmsg_ptr;
- int total_len, len;
+ int len;
  ssize_t err;
 
  /* kernel mode address */
@@ -2091,7 +2090,6 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
  err = copy_msghdr_from_user(msg_sys, msg, &uaddr, &iov);
  if (err < 0)
  return err;
- total_len = iov_iter_count(&msg_sys->msg_iter);
 
  cmsg_ptr = (unsigned long)msg_sys->msg_control;
  msg_sys->msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
@@ -2101,8 +2099,7 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
 
  if (sock->file->f_flags & O_NONBLOCK)
  flags |= MSG_DONTWAIT;
- err = (nosec ? sock_recvmsg_nosec : sock_recvmsg)(sock, msg_sys,
-  total_len, flags);
+ err = (nosec ? sock_recvmsg_nosec : sock_recvmsg)(sock, msg_sys, flags);
  if (err < 0)
  goto out_freeiov;
  len = err;
--
2.8.0.rc3

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[PATCH 2/6] cifs: merge the hash calculation helpers

Al Viro-3
In reply to this post by Al Viro-3
three practically identical copies...

Signed-off-by: Al Viro <[hidden email]>
---
 fs/cifs/cifsencrypt.c   |  97 ++++++++++++++++++++++++-------------------
 fs/cifs/cifsproto.h     |   3 ++
 fs/cifs/smb2transport.c | 107 +++++-------------------------------------------
 3 files changed, 67 insertions(+), 140 deletions(-)

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 4897dac..6aeb8d4 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -66,45 +66,15 @@ cifs_crypto_shash_md5_allocate(struct TCP_Server_Info *server)
  return 0;
 }
 
-/*
- * Calculate and return the CIFS signature based on the mac key and SMB PDU.
- * The 16 byte signature must be allocated by the caller. Note we only use the
- * 1st eight bytes and that the smb header signature field on input contains
- * the sequence number before this function is called. Also, this function
- * should be called with the server->srv_mutex held.
- */
-static int cifs_calc_signature(struct smb_rqst *rqst,
- struct TCP_Server_Info *server, char *signature)
+int __cifs_calc_signature(struct smb_rqst *rqst,
+ struct TCP_Server_Info *server, char *signature,
+ struct shash_desc *shash)
 {
  int i;
  int rc;
  struct kvec *iov = rqst->rq_iov;
  int n_vec = rqst->rq_nvec;
 
- if (iov == NULL || signature == NULL || server == NULL)
- return -EINVAL;
-
- if (!server->secmech.sdescmd5) {
- rc = cifs_crypto_shash_md5_allocate(server);
- if (rc) {
- cifs_dbg(VFS, "%s: Can't alloc md5 crypto\n", __func__);
- return -1;
- }
- }
-
- rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
- if (rc) {
- cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
- return rc;
- }
-
- rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
- server->session_key.response, server->session_key.len);
- if (rc) {
- cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
- return rc;
- }
-
  for (i = 0; i < n_vec; i++) {
  if (iov[i].iov_len == 0)
  continue;
@@ -117,12 +87,10 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
  if (i == 0) {
  if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
  break; /* nothing to sign or corrupt header */
- rc =
- crypto_shash_update(&server->secmech.sdescmd5->shash,
+ rc = crypto_shash_update(shash,
  iov[i].iov_base + 4, iov[i].iov_len - 4);
  } else {
- rc =
- crypto_shash_update(&server->secmech.sdescmd5->shash,
+ rc = crypto_shash_update(shash,
  iov[i].iov_base, iov[i].iov_len);
  }
  if (rc) {
@@ -134,21 +102,64 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
 
  /* now hash over the rq_pages array */
  for (i = 0; i < rqst->rq_npages; i++) {
- struct kvec p_iov;
+ void *kaddr = kmap(rqst->rq_pages[i]);
+ size_t len = rqst->rq_pagesz;
+
+ if (i == rqst->rq_npages - 1)
+ len = rqst->rq_tailsz;
+
+ crypto_shash_update(shash, kaddr, len);
 
- cifs_rqst_page_to_kvec(rqst, i, &p_iov);
- crypto_shash_update(&server->secmech.sdescmd5->shash,
- p_iov.iov_base, p_iov.iov_len);
  kunmap(rqst->rq_pages[i]);
  }
 
- rc = crypto_shash_final(&server->secmech.sdescmd5->shash, signature);
+ rc = crypto_shash_final(shash, signature);
  if (rc)
- cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
+ cifs_dbg(VFS, "%s: Could not generate hash\n", __func__);
 
  return rc;
 }
 
+/*
+ * Calculate and return the CIFS signature based on the mac key and SMB PDU.
+ * The 16 byte signature must be allocated by the caller. Note we only use the
+ * 1st eight bytes and that the smb header signature field on input contains
+ * the sequence number before this function is called. Also, this function
+ * should be called with the server->srv_mutex held.
+ */
+static int cifs_calc_signature(struct smb_rqst *rqst,
+ struct TCP_Server_Info *server, char *signature)
+{
+ int rc;
+
+ if (!rqst->rq_iov || !signature || !server)
+ return -EINVAL;
+
+ if (!server->secmech.sdescmd5) {
+ rc = cifs_crypto_shash_md5_allocate(server);
+ if (rc) {
+ cifs_dbg(VFS, "%s: Can't alloc md5 crypto\n", __func__);
+ return -1;
+ }
+ }
+
+ rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
+ if (rc) {
+ cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
+ return rc;
+ }
+
+ rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
+ server->session_key.response, server->session_key.len);
+ if (rc) {
+ cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
+ return rc;
+ }
+
+ return __cifs_calc_signature(rqst, server, signature,
+     &server->secmech.sdescmd5->shash);
+}
+
 /* must be called with server->srv_mutex held */
 int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server,
    __u32 *pexpected_response_sequence_number)
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index eed7ff5..d9b4f44 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -512,4 +512,7 @@ int cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
    struct cifs_sb_info *cifs_sb,
    const unsigned char *path, char *pbuf,
    unsigned int *pbytes_written);
+int __cifs_calc_signature(struct smb_rqst *rqst,
+ struct TCP_Server_Info *server, char *signature,
+ struct shash_desc *shash);
 #endif /* _CIFSPROTO_H */
diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index 8732a43..bc9a7b6 100644
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -135,11 +135,10 @@ smb2_find_smb_ses(struct smb2_hdr *smb2hdr, struct TCP_Server_Info *server)
 int
 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 {
- int i, rc;
+ int rc;
  unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
  unsigned char *sigptr = smb2_signature;
  struct kvec *iov = rqst->rq_iov;
- int n_vec = rqst->rq_nvec;
  struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
  struct cifs_ses *ses;
 
@@ -171,53 +170,11 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
  return rc;
  }
 
- for (i = 0; i < n_vec; i++) {
- if (iov[i].iov_len == 0)
- continue;
- if (iov[i].iov_base == NULL) {
- cifs_dbg(VFS, "null iovec entry\n");
- return -EIO;
- }
- /*
- * The first entry includes a length field (which does not get
- * signed that occupies the first 4 bytes before the header).
- */
- if (i == 0) {
- if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
- break; /* nothing to sign or corrupt header */
- rc =
- crypto_shash_update(
- &server->secmech.sdeschmacsha256->shash,
- iov[i].iov_base + 4, iov[i].iov_len - 4);
- } else {
- rc =
- crypto_shash_update(
- &server->secmech.sdeschmacsha256->shash,
- iov[i].iov_base, iov[i].iov_len);
- }
- if (rc) {
- cifs_dbg(VFS, "%s: Could not update with payload\n",
- __func__);
- return rc;
- }
- }
-
- /* now hash over the rq_pages array */
- for (i = 0; i < rqst->rq_npages; i++) {
- struct kvec p_iov;
-
- cifs_rqst_page_to_kvec(rqst, i, &p_iov);
- crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
- p_iov.iov_base, p_iov.iov_len);
- kunmap(rqst->rq_pages[i]);
- }
-
- rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
- sigptr);
- if (rc)
- cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
+ rc = __cifs_calc_signature(rqst, server, sigptr,
+ &server->secmech.sdeschmacsha256->shash);
 
- memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
+ if (!rc)
+ memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 
  return rc;
 }
@@ -395,12 +352,10 @@ generate_smb311signingkey(struct cifs_ses *ses)
 int
 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 {
- int i;
  int rc = 0;
  unsigned char smb3_signature[SMB2_CMACAES_SIZE];
  unsigned char *sigptr = smb3_signature;
  struct kvec *iov = rqst->rq_iov;
- int n_vec = rqst->rq_nvec;
  struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
  struct cifs_ses *ses;
 
@@ -431,54 +386,12 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
  cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
  return rc;
  }
+
+ rc = __cifs_calc_signature(rqst, server, sigptr,
+   &server->secmech.sdesccmacaes->shash);
 
- for (i = 0; i < n_vec; i++) {
- if (iov[i].iov_len == 0)
- continue;
- if (iov[i].iov_base == NULL) {
- cifs_dbg(VFS, "null iovec entry");
- return -EIO;
- }
- /*
- * The first entry includes a length field (which does not get
- * signed that occupies the first 4 bytes before the header).
- */
- if (i == 0) {
- if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
- break; /* nothing to sign or corrupt header */
- rc =
- crypto_shash_update(
- &server->secmech.sdesccmacaes->shash,
- iov[i].iov_base + 4, iov[i].iov_len - 4);
- } else {
- rc =
- crypto_shash_update(
- &server->secmech.sdesccmacaes->shash,
- iov[i].iov_base, iov[i].iov_len);
- }
- if (rc) {
- cifs_dbg(VFS, "%s: Couldn't update cmac aes with payload\n",
- __func__);
- return rc;
- }
- }
-
- /* now hash over the rq_pages array */
- for (i = 0; i < rqst->rq_npages; i++) {
- struct kvec p_iov;
-
- cifs_rqst_page_to_kvec(rqst, i, &p_iov);
- crypto_shash_update(&server->secmech.sdesccmacaes->shash,
- p_iov.iov_base, p_iov.iov_len);
- kunmap(rqst->rq_pages[i]);
- }
-
- rc = crypto_shash_final(&server->secmech.sdesccmacaes->shash,
- sigptr);
- if (rc)
- cifs_dbg(VFS, "%s: Could not generate cmac aes\n", __func__);
-
- memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
+ if (!rc)
+ memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 
  return rc;
 }
--
2.8.0.rc3

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[PATCH 3/6] cifs: quit playing games with draining iovecs

Al Viro-3
In reply to this post by Al Viro-3
... and use ITER_BVEC for the page part of request to send

Signed-off-by: Al Viro <[hidden email]>
---
 fs/cifs/cifsproto.h |   2 -
 fs/cifs/transport.c | 141 +++++++++++++++-------------------------------------
 2 files changed, 41 insertions(+), 102 deletions(-)

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index d9b4f44..7d5f53a 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -37,8 +37,6 @@ extern void cifs_buf_release(void *);
 extern struct smb_hdr *cifs_small_buf_get(void);
 extern void cifs_small_buf_release(void *);
 extern void free_rsp_buf(int, void *);
-extern void cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx,
- struct kvec *iov);
 extern int smb_send(struct TCP_Server_Info *, struct smb_hdr *,
  unsigned int /* length */);
 extern unsigned int _get_xid(void);
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 87abe8e..206a597 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -124,41 +124,32 @@ cifs_delete_mid(struct mid_q_entry *mid)
 /*
  * smb_send_kvec - send an array of kvecs to the server
  * @server: Server to send the data to
- * @iov: Pointer to array of kvecs
- * @n_vec: length of kvec array
+ * @smb_msg: Message to send
  * @sent: amount of data sent on socket is stored here
  *
  * Our basic "send data to server" function. Should be called with srv_mutex
  * held. The caller is responsible for handling the results.
  */
 static int
-smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov, size_t n_vec,
- size_t *sent)
+smb_send_kvec(struct TCP_Server_Info *server, struct msghdr *smb_msg,
+      size_t *sent)
 {
  int rc = 0;
- int i = 0;
- struct msghdr smb_msg;
- unsigned int remaining;
- size_t first_vec = 0;
+ int retries = 0;
  struct socket *ssocket = server->ssocket;
 
  *sent = 0;
 
- smb_msg.msg_name = (struct sockaddr *) &server->dstaddr;
- smb_msg.msg_namelen = sizeof(struct sockaddr);
- smb_msg.msg_control = NULL;
- smb_msg.msg_controllen = 0;
+ smb_msg->msg_name = (struct sockaddr *) &server->dstaddr;
+ smb_msg->msg_namelen = sizeof(struct sockaddr);
+ smb_msg->msg_control = NULL;
+ smb_msg->msg_controllen = 0;
  if (server->noblocksnd)
- smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
+ smb_msg->msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
  else
- smb_msg.msg_flags = MSG_NOSIGNAL;
-
- remaining = 0;
- for (i = 0; i < n_vec; i++)
- remaining += iov[i].iov_len;
+ smb_msg->msg_flags = MSG_NOSIGNAL;
 
- i = 0;
- while (remaining) {
+ while (msg_data_left(smb_msg)) {
  /*
  * If blocking send, we try 3 times, since each can block
  * for 5 seconds. For nonblocking  we have to try more
@@ -177,35 +168,21 @@ smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov, size_t n_vec,
  * after the retries we will kill the socket and
  * reconnect which may clear the network problem.
  */
- rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
-    n_vec - first_vec, remaining);
+ rc = sock_sendmsg(ssocket, smb_msg);
  if (rc == -EAGAIN) {
- i++;
- if (i >= 14 || (!server->noblocksnd && (i > 2))) {
+ retries++;
+ if (retries >= 14 ||
+    (!server->noblocksnd && (retries > 2))) {
  cifs_dbg(VFS, "sends on sock %p stuck for 15 seconds\n",
  ssocket);
- rc = -EAGAIN;
- break;
+ return -EAGAIN;
  }
- msleep(1 << i);
+ msleep(1 << retries);
  continue;
  }
 
  if (rc < 0)
- break;
-
- /* send was at least partially successful */
- *sent += rc;
-
- if (rc == remaining) {
- remaining = 0;
- break;
- }
-
- if (rc > remaining) {
- cifs_dbg(VFS, "sent %d requested %d\n", rc, remaining);
- break;
- }
+ return rc;
 
  if (rc == 0) {
  /* should never happen, letting socket clear before
@@ -215,59 +192,11 @@ smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov, size_t n_vec,
  continue;
  }
 
- remaining -= rc;
-
- /* the line below resets i */
- for (i = first_vec; i < n_vec; i++) {
- if (iov[i].iov_len) {
- if (rc > iov[i].iov_len) {
- rc -= iov[i].iov_len;
- iov[i].iov_len = 0;
- } else {
- iov[i].iov_base += rc;
- iov[i].iov_len -= rc;
- first_vec = i;
- break;
- }
- }
- }
-
- i = 0; /* in case we get ENOSPC on the next send */
- rc = 0;
+ /* send was at least partially successful */
+ *sent += rc;
+ retries = 0; /* in case we get ENOSPC on the next send */
  }
- return rc;
-}
-
-/**
- * rqst_page_to_kvec - Turn a slot in the smb_rqst page array into a kvec
- * @rqst: pointer to smb_rqst
- * @idx: index into the array of the page
- * @iov: pointer to struct kvec that will hold the result
- *
- * Helper function to convert a slot in the rqst->rq_pages array into a kvec.
- * The page will be kmapped and the address placed into iov_base. The length
- * will then be adjusted according to the ptailoff.
- */
-void
-cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx,
- struct kvec *iov)
-{
- /*
- * FIXME: We could avoid this kmap altogether if we used
- * kernel_sendpage instead of kernel_sendmsg. That will only
- * work if signing is disabled though as sendpage inlines the
- * page directly into the fraglist. If userspace modifies the
- * page after we calculate the signature, then the server will
- * reject it and may break the connection. kernel_sendmsg does
- * an extra copy of the data and avoids that issue.
- */
- iov->iov_base = kmap(rqst->rq_pages[idx]);
-
- /* if last page, don't send beyond this offset into page */
- if (idx == (rqst->rq_npages - 1))
- iov->iov_len = rqst->rq_tailsz;
- else
- iov->iov_len = rqst->rq_pagesz;
+ return 0;
 }
 
 static unsigned long
@@ -299,8 +228,9 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
  unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
  unsigned long send_length;
  unsigned int i;
- size_t total_len = 0, sent;
+ size_t total_len = 0, sent, size;
  struct socket *ssocket = server->ssocket;
+ struct msghdr smb_msg;
  int val = 1;
 
  if (ssocket == NULL)
@@ -321,7 +251,13 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
  kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
  (char *)&val, sizeof(val));
 
- rc = smb_send_kvec(server, iov, n_vec, &sent);
+ size = 0;
+ for (i = 0; i < n_vec; i++)
+ size += iov[i].iov_len;
+
+ iov_iter_kvec(&smb_msg.msg_iter, WRITE | ITER_KVEC, iov, n_vec, size);
+
+ rc = smb_send_kvec(server, &smb_msg, &sent);
  if (rc < 0)
  goto uncork;
 
@@ -329,11 +265,16 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 
  /* now walk the page array and send each page in it */
  for (i = 0; i < rqst->rq_npages; i++) {
- struct kvec p_iov;
-
- cifs_rqst_page_to_kvec(rqst, i, &p_iov);
- rc = smb_send_kvec(server, &p_iov, 1, &sent);
- kunmap(rqst->rq_pages[i]);
+ size_t len = i == rqst->rq_npages - 1
+ ? rqst->rq_tailsz
+ : rqst->rq_pagesz;
+ struct bio_vec bvec = {
+ .bv_page = rqst->rq_pages[i],
+ .bv_len = len
+ };
+ iov_iter_bvec(&smb_msg.msg_iter, WRITE | ITER_BVEC,
+      &bvec, 1, len);
+ rc = smb_send_kvec(server, &smb_msg, &sent);
  if (rc < 0)
  break;
 
--
2.8.0.rc3

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[PATCH 4/6] cifs: no need to wank with copying and advancing iovec on recvmsg side either

Al Viro-3
In reply to this post by Al Viro-3
Signed-off-by: Al Viro <[hidden email]>
---
 fs/cifs/cifsglob.h |  2 --
 fs/cifs/connect.c  | 72 ++++--------------------------------------------------
 2 files changed, 5 insertions(+), 69 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index d21da9f..df03c5e 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -615,8 +615,6 @@ struct TCP_Server_Info {
  bool sec_mskerberos; /* supports legacy MS Kerberos */
  bool large_buf; /* is current buffer large? */
  struct delayed_work echo; /* echo ping workqueue job */
- struct kvec *iov; /* reusable kvec array for receives */
- unsigned int nr_iov; /* number of kvecs in array */
  char *smallbuf; /* pointer to current "small" buffer */
  char *bigbuf; /* pointer to current "big" buffer */
  unsigned int total_read; /* total amount of data read in this pass */
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a763cd3..eb42665 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -501,77 +501,20 @@ server_unresponsive(struct TCP_Server_Info *server)
  return false;
 }
 
-/*
- * kvec_array_init - clone a kvec array, and advance into it
- * @new: pointer to memory for cloned array
- * @iov: pointer to original array
- * @nr_segs: number of members in original array
- * @bytes: number of bytes to advance into the cloned array
- *
- * This function will copy the array provided in iov to a section of memory
- * and advance the specified number of bytes into the new array. It returns
- * the number of segments in the new array. "new" must be at least as big as
- * the original iov array.
- */
-static unsigned int
-kvec_array_init(struct kvec *new, struct kvec *iov, unsigned int nr_segs,
- size_t bytes)
-{
- size_t base = 0;
-
- while (bytes || !iov->iov_len) {
- int copy = min(bytes, iov->iov_len);
-
- bytes -= copy;
- base += copy;
- if (iov->iov_len == base) {
- iov++;
- nr_segs--;
- base = 0;
- }
- }
- memcpy(new, iov, sizeof(*iov) * nr_segs);
- new->iov_base += base;
- new->iov_len -= base;
- return nr_segs;
-}
-
-static struct kvec *
-get_server_iovec(struct TCP_Server_Info *server, unsigned int nr_segs)
-{
- struct kvec *new_iov;
-
- if (server->iov && nr_segs <= server->nr_iov)
- return server->iov;
-
- /* not big enough -- allocate a new one and release the old */
- new_iov = kmalloc(sizeof(*new_iov) * nr_segs, GFP_NOFS);
- if (new_iov) {
- kfree(server->iov);
- server->iov = new_iov;
- server->nr_iov = nr_segs;
- }
- return new_iov;
-}
-
 int
 cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
        unsigned int nr_segs, unsigned int to_read)
 {
  int length = 0;
  int total_read;
- unsigned int segs;
  struct msghdr smb_msg;
- struct kvec *iov;
-
- iov = get_server_iovec(server, nr_segs);
- if (!iov)
- return -ENOMEM;
 
  smb_msg.msg_control = NULL;
  smb_msg.msg_controllen = 0;
+ iov_iter_kvec(&smb_msg.msg_iter, READ | ITER_KVEC,
+      iov_orig, nr_segs, to_read);
 
- for (total_read = 0; to_read; total_read += length, to_read -= length) {
+ for (total_read = 0; msg_data_left(&smb_msg); total_read += length) {
  try_to_freeze();
 
  if (server_unresponsive(server)) {
@@ -579,10 +522,7 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
  break;
  }
 
- segs = kvec_array_init(iov, iov_orig, nr_segs, total_read);
-
- length = kernel_recvmsg(server->ssocket, &smb_msg,
- iov, segs, to_read, 0);
+ length = sock_recvmsg(server->ssocket, &smb_msg, 0);
 
  if (server->tcpStatus == CifsExiting) {
  total_read = -ESHUTDOWN;
@@ -603,8 +543,7 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
  length = 0;
  continue;
  } else if (length <= 0) {
- cifs_dbg(FYI, "Received no data or error: expecting %d\n"
- "got %d", to_read, length);
+ cifs_dbg(FYI, "Received no data or error: %d\n", length);
  cifs_reconnect(server);
  total_read = -ECONNABORTED;
  break;
@@ -783,7 +722,6 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server)
  }
 
  kfree(server->hostname);
- kfree(server->iov);
  kfree(server);
 
  length = atomic_dec_return(&tcpSesAllocCount);
--
2.8.0.rc3

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[PATCH 5/6] cifs_readv_receive: use cifs_read_from_socket()

Al Viro-3
In reply to this post by Al Viro-3
Signed-off-by: Al Viro <[hidden email]>
---
 fs/cifs/cifssmb.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 76fcb50..3da077a 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1447,10 +1447,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
  len = min_t(unsigned int, buflen, server->vals->read_rsp_size) -
  HEADER_SIZE(server) + 1;
 
- rdata->iov.iov_base = buf + HEADER_SIZE(server) - 1;
- rdata->iov.iov_len = len;
-
- length = cifs_readv_from_socket(server, &rdata->iov, 1, len);
+ length = cifs_read_from_socket(server,
+       buf + HEADER_SIZE(server) - 1, len);
  if (length < 0)
  return length;
  server->total_read += length;
@@ -1502,9 +1500,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
  len = data_offset - server->total_read;
  if (len > 0) {
  /* read any junk before data into the rest of smallbuf */
- rdata->iov.iov_base = buf + server->total_read;
- rdata->iov.iov_len = len;
- length = cifs_readv_from_socket(server, &rdata->iov, 1, len);
+ length = cifs_read_from_socket(server,
+       buf + server->total_read, len);
  if (length < 0)
  return length;
  server->total_read += length;
--
2.8.0.rc3

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[PATCH 6/6] cifs: don't bother with kmap on read_pages side

Al Viro-3
In reply to this post by Al Viro-3
just do ITER_BVEC recvmsg

Signed-off-by: Al Viro <[hidden email]>
---
 fs/cifs/cifsproto.h |  7 +++---
 fs/cifs/connect.c   | 65 ++++++++++++++++++++++++++++-------------------------
 fs/cifs/file.c      | 53 ++++++++++++++-----------------------------
 3 files changed, 55 insertions(+), 70 deletions(-)

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 7d5f53a..0f9a6bc 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -179,10 +179,9 @@ extern int set_cifs_acl(struct cifs_ntsd *, __u32, struct inode *,
 
 extern void dequeue_mid(struct mid_q_entry *mid, bool malformed);
 extern int cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
-     unsigned int to_read);
-extern int cifs_readv_from_socket(struct TCP_Server_Info *server,
- struct kvec *iov_orig, unsigned int nr_segs,
- unsigned int to_read);
+         unsigned int to_read);
+extern int cifs_read_page_from_socket(struct TCP_Server_Info *server,
+      struct page *page, unsigned int to_read);
 extern void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
        struct cifs_sb_info *cifs_sb);
 extern int cifs_match_super(struct super_block *, void *);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index eb42665..e33c5e0 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -501,39 +501,34 @@ server_unresponsive(struct TCP_Server_Info *server)
  return false;
 }
 
-int
-cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
-       unsigned int nr_segs, unsigned int to_read)
+static int
+cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
 {
  int length = 0;
  int total_read;
- struct msghdr smb_msg;
 
- smb_msg.msg_control = NULL;
- smb_msg.msg_controllen = 0;
- iov_iter_kvec(&smb_msg.msg_iter, READ | ITER_KVEC,
-      iov_orig, nr_segs, to_read);
+ smb_msg->msg_control = NULL;
+ smb_msg->msg_controllen = 0;
 
- for (total_read = 0; msg_data_left(&smb_msg); total_read += length) {
+ for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
  try_to_freeze();
 
- if (server_unresponsive(server)) {
- total_read = -ECONNABORTED;
- break;
- }
+ if (server_unresponsive(server))
+ return -ECONNABORTED;
 
- length = sock_recvmsg(server->ssocket, &smb_msg, 0);
+ length = sock_recvmsg(server->ssocket, smb_msg, 0);
 
- if (server->tcpStatus == CifsExiting) {
- total_read = -ESHUTDOWN;
- break;
- } else if (server->tcpStatus == CifsNeedReconnect) {
+ if (server->tcpStatus == CifsExiting)
+ return -ESHUTDOWN;
+
+ if (server->tcpStatus == CifsNeedReconnect) {
  cifs_reconnect(server);
- total_read = -ECONNABORTED;
- break;
- } else if (length == -ERESTARTSYS ||
-   length == -EAGAIN ||
-   length == -EINTR) {
+ return -ECONNABORTED;
+ }
+
+ if (length == -ERESTARTSYS ||
+    length == -EAGAIN ||
+    length == -EINTR) {
  /*
  * Minimum sleep to prevent looping, allowing socket
  * to clear and app threads to set tcpStatus
@@ -542,11 +537,12 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
  usleep_range(1000, 2000);
  length = 0;
  continue;
- } else if (length <= 0) {
+ }
+
+ if (length <= 0) {
  cifs_dbg(FYI, "Received no data or error: %d\n", length);
  cifs_reconnect(server);
- total_read = -ECONNABORTED;
- break;
+ return -ECONNABORTED;
  }
  }
  return total_read;
@@ -556,12 +552,21 @@ int
 cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
       unsigned int to_read)
 {
- struct kvec iov;
+ struct msghdr smb_msg;
+ struct kvec iov = {.iov_base = buf, .iov_len = to_read};
+ iov_iter_kvec(&smb_msg.msg_iter, READ | ITER_KVEC, &iov, 1, to_read);
 
- iov.iov_base = buf;
- iov.iov_len = to_read;
+ return cifs_readv_from_socket(server, &smb_msg);
+}
 
- return cifs_readv_from_socket(server, &iov, 1, to_read);
+int
+cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
+      unsigned int to_read)
+{
+ struct msghdr smb_msg;
+ struct bio_vec bv = {.bv_page = page, .bv_len = to_read};
+ iov_iter_bvec(&smb_msg.msg_iter, READ | ITER_BVEC, &bv, 1, to_read);
+ return cifs_readv_from_socket(server, &smb_msg);
 }
 
 static bool
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index ff882ae..0f71867 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2855,39 +2855,31 @@ cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
  int result = 0;
  unsigned int i;
  unsigned int nr_pages = rdata->nr_pages;
- struct kvec iov;
 
  rdata->got_bytes = 0;
  rdata->tailsz = PAGE_SIZE;
  for (i = 0; i < nr_pages; i++) {
  struct page *page = rdata->pages[i];
+ size_t n;
 
- if (len >= PAGE_SIZE) {
- /* enough data to fill the page */
- iov.iov_base = kmap(page);
- iov.iov_len = PAGE_SIZE;
- cifs_dbg(FYI, "%u: iov_base=%p iov_len=%zu\n",
- i, iov.iov_base, iov.iov_len);
- len -= PAGE_SIZE;
- } else if (len > 0) {
- /* enough for partial page, fill and zero the rest */
- iov.iov_base = kmap(page);
- iov.iov_len = len;
- cifs_dbg(FYI, "%u: iov_base=%p iov_len=%zu\n",
- i, iov.iov_base, iov.iov_len);
- memset(iov.iov_base + len, '\0', PAGE_SIZE - len);
- rdata->tailsz = len;
- len = 0;
- } else {
+ if (len <= 0) {
  /* no need to hold page hostage */
  rdata->pages[i] = NULL;
  rdata->nr_pages--;
  put_page(page);
  continue;
  }
-
- result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
- kunmap(page);
+ n = len;
+ if (len >= PAGE_SIZE) {
+ /* enough data to fill the page */
+ n = PAGE_SIZE;
+ len -= n;
+ } else {
+ zero_user(page, len, PAGE_SIZE - len);
+ rdata->tailsz = len;
+ len = 0;
+ }
+ result = cifs_read_page_from_socket(server, page, n);
  if (result < 0)
  break;
 
@@ -3303,7 +3295,6 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
  u64 eof;
  pgoff_t eof_index;
  unsigned int nr_pages = rdata->nr_pages;
- struct kvec iov;
 
  /* determine the eof that the server (probably) has */
  eof = CIFS_I(rdata->mapping->host)->server_eof;
@@ -3314,23 +3305,14 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
  rdata->tailsz = PAGE_CACHE_SIZE;
  for (i = 0; i < nr_pages; i++) {
  struct page *page = rdata->pages[i];
+ size_t n = PAGE_CACHE_SIZE;
 
  if (len >= PAGE_CACHE_SIZE) {
- /* enough data to fill the page */
- iov.iov_base = kmap(page);
- iov.iov_len = PAGE_CACHE_SIZE;
- cifs_dbg(FYI, "%u: idx=%lu iov_base=%p iov_len=%zu\n",
- i, page->index, iov.iov_base, iov.iov_len);
  len -= PAGE_CACHE_SIZE;
  } else if (len > 0) {
  /* enough for partial page, fill and zero the rest */
- iov.iov_base = kmap(page);
- iov.iov_len = len;
- cifs_dbg(FYI, "%u: idx=%lu iov_base=%p iov_len=%zu\n",
- i, page->index, iov.iov_base, iov.iov_len);
- memset(iov.iov_base + len,
- '\0', PAGE_CACHE_SIZE - len);
- rdata->tailsz = len;
+ zero_user(page, len, PAGE_CACHE_SIZE - len);
+ n = rdata->tailsz = len;
  len = 0;
  } else if (page->index > eof_index) {
  /*
@@ -3360,8 +3342,7 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
  continue;
  }
 
- result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
- kunmap(page);
+ result = cifs_read_page_from_socket(server, page, n);
  if (result < 0)
  break;
 
--
2.8.0.rc3

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Re: [RFC][PATCHSET] reduce messing with iovecs in cifs

Shirish Pargaonkar
In reply to this post by Al Viro-3
Looking at the series. I briefly looked at 2/6 and looks correct but
would add tested-by once I test that patch
against a SMB server.

On Sat, Apr 9, 2016 at 3:43 PM, Al Viro <[hidden email]> wrote:

>         Now that sendmsg/recvmsg do not mangle iovecs and are capable of
> handling bvec-based ->msg_iter, we can seriously reduce the amount of PITA
> in cifs.  The series below is completely untested, and I would appreciate
> comments/review/testing/etc.
>
> I'll post the individual patches in followups; for those who prefer to use
> git it can be found in
> git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git sendmsg.cifs
>
> 1/6: [net] drop 'size' argument of sock_recvmsg()
>         should go via net-next; does what it says.
>
> 2/6: cifs: merge the hash calculation helpers
>         takes the common parts of {cifs,smb2,smb3}_calc_signature() into a
> common helper.
>
> 3/6: cifs: quit playing games with draining iovecs
>         Switch smb_send_kvec() to passing msghdr (and thus iov_iter) and
> make it use sock_sendmsg() - that allows to avoid draining iovecs, since
> ->msg_iter will be advanced properly and all we need is to keep it around
> between the calls of sock_sendmsg(), rather than reinitializing it on each
> loop iteration.  The same thing allows to get rid of messing with kmap()
> when sending the stuff in ->rq_pages[] - ITER_BVEC will do the right thing.
>
> 4/6: cifs: no need to wank with copying and advancing iovec on recvmsg side either
>         Similar to the previous - use sock_recvmsg() in cifs_readv_from_socket()
> and there's no need to modify iovecs, or allocate a copy especially for
> such modifications, etc.
>
> 5/6: cifs_readv_receive: use cifs_read_from_socket()
>         building a 1-element iovec array for cifs_readv_from_socket() is
> an overkill - simple cifs_read_from_socket() will do just fine.
>
> 6/6: cifs: don't bother with kmap on read_pages side
>         Similar to the other half of 3/6: we can use ITER_BVEC for
> read-into-page case.  Just make cifs_readv_from_socket() take msghdr from
> caller and use a helper that would feed it a bvec-backed ->msg_iter.
> --
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> the body of a message to [hidden email]
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Re: [PATCH 2/6] cifs: merge the hash calculation helpers

Shirish Pargaonkar
In reply to this post by Al Viro-3
Looks correct.
Tested with -o vers=1.0, -o vers=2.0, and -o vers=2.1.
Will test using mount option vers=3.0 as soon as I find a server.

Reviewed-by: Shirish Pargaonkar <[hidden email]>
Tested-by: Shirish Pargaonkar <[hidden email]>

On Sat, Apr 9, 2016 at 3:50 PM, Al Viro <[hidden email]> wrote:

> three practically identical copies...
>
> Signed-off-by: Al Viro <[hidden email]>
> ---
>  fs/cifs/cifsencrypt.c   |  97 ++++++++++++++++++++++++-------------------
>  fs/cifs/cifsproto.h     |   3 ++
>  fs/cifs/smb2transport.c | 107 +++++-------------------------------------------
>  3 files changed, 67 insertions(+), 140 deletions(-)
>
> diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
> index 4897dac..6aeb8d4 100644
> --- a/fs/cifs/cifsencrypt.c
> +++ b/fs/cifs/cifsencrypt.c
> @@ -66,45 +66,15 @@ cifs_crypto_shash_md5_allocate(struct TCP_Server_Info *server)
>         return 0;
>  }
>
> -/*
> - * Calculate and return the CIFS signature based on the mac key and SMB PDU.
> - * The 16 byte signature must be allocated by the caller. Note we only use the
> - * 1st eight bytes and that the smb header signature field on input contains
> - * the sequence number before this function is called. Also, this function
> - * should be called with the server->srv_mutex held.
> - */
> -static int cifs_calc_signature(struct smb_rqst *rqst,
> -                       struct TCP_Server_Info *server, char *signature)
> +int __cifs_calc_signature(struct smb_rqst *rqst,
> +                       struct TCP_Server_Info *server, char *signature,
> +                       struct shash_desc *shash)
>  {
>         int i;
>         int rc;
>         struct kvec *iov = rqst->rq_iov;
>         int n_vec = rqst->rq_nvec;
>
> -       if (iov == NULL || signature == NULL || server == NULL)
> -               return -EINVAL;
> -
> -       if (!server->secmech.sdescmd5) {
> -               rc = cifs_crypto_shash_md5_allocate(server);
> -               if (rc) {
> -                       cifs_dbg(VFS, "%s: Can't alloc md5 crypto\n", __func__);
> -                       return -1;
> -               }
> -       }
> -
> -       rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
> -       if (rc) {
> -               cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
> -               return rc;
> -       }
> -
> -       rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
> -               server->session_key.response, server->session_key.len);
> -       if (rc) {
> -               cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
> -               return rc;
> -       }
> -
>         for (i = 0; i < n_vec; i++) {
>                 if (iov[i].iov_len == 0)
>                         continue;
> @@ -117,12 +87,10 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
>                 if (i == 0) {
>                         if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
>                                 break; /* nothing to sign or corrupt header */
> -                       rc =
> -                       crypto_shash_update(&server->secmech.sdescmd5->shash,
> +                       rc = crypto_shash_update(shash,
>                                 iov[i].iov_base + 4, iov[i].iov_len - 4);
>                 } else {
> -                       rc =
> -                       crypto_shash_update(&server->secmech.sdescmd5->shash,
> +                       rc = crypto_shash_update(shash,
>                                 iov[i].iov_base, iov[i].iov_len);
>                 }
>                 if (rc) {
> @@ -134,21 +102,64 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
>
>         /* now hash over the rq_pages array */
>         for (i = 0; i < rqst->rq_npages; i++) {
> -               struct kvec p_iov;
> +               void *kaddr = kmap(rqst->rq_pages[i]);
> +               size_t len = rqst->rq_pagesz;
> +
> +               if (i == rqst->rq_npages - 1)
> +                       len = rqst->rq_tailsz;
> +
> +               crypto_shash_update(shash, kaddr, len);
>
> -               cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> -               crypto_shash_update(&server->secmech.sdescmd5->shash,
> -                                       p_iov.iov_base, p_iov.iov_len);
>                 kunmap(rqst->rq_pages[i]);
>         }
>
> -       rc = crypto_shash_final(&server->secmech.sdescmd5->shash, signature);
> +       rc = crypto_shash_final(shash, signature);
>         if (rc)
> -               cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
> +               cifs_dbg(VFS, "%s: Could not generate hash\n", __func__);
>
>         return rc;
>  }
>
> +/*
> + * Calculate and return the CIFS signature based on the mac key and SMB PDU.
> + * The 16 byte signature must be allocated by the caller. Note we only use the
> + * 1st eight bytes and that the smb header signature field on input contains
> + * the sequence number before this function is called. Also, this function
> + * should be called with the server->srv_mutex held.
> + */
> +static int cifs_calc_signature(struct smb_rqst *rqst,
> +                       struct TCP_Server_Info *server, char *signature)
> +{
> +       int rc;
> +
> +       if (!rqst->rq_iov || !signature || !server)
> +               return -EINVAL;
> +
> +       if (!server->secmech.sdescmd5) {
> +               rc = cifs_crypto_shash_md5_allocate(server);
> +               if (rc) {
> +                       cifs_dbg(VFS, "%s: Can't alloc md5 crypto\n", __func__);
> +                       return -1;
> +               }
> +       }
> +
> +       rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
> +       if (rc) {
> +               cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
> +               return rc;
> +       }
> +
> +       rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
> +               server->session_key.response, server->session_key.len);
> +       if (rc) {
> +               cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
> +               return rc;
> +       }
> +
> +       return __cifs_calc_signature(rqst, server, signature,
> +                                    &server->secmech.sdescmd5->shash);
> +}
> +
>  /* must be called with server->srv_mutex held */
>  int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server,
>                    __u32 *pexpected_response_sequence_number)
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index eed7ff5..d9b4f44 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -512,4 +512,7 @@ int cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
>                            struct cifs_sb_info *cifs_sb,
>                            const unsigned char *path, char *pbuf,
>                            unsigned int *pbytes_written);
> +int __cifs_calc_signature(struct smb_rqst *rqst,
> +                       struct TCP_Server_Info *server, char *signature,
> +                       struct shash_desc *shash);
>  #endif                 /* _CIFSPROTO_H */
> diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
> index 8732a43..bc9a7b6 100644
> --- a/fs/cifs/smb2transport.c
> +++ b/fs/cifs/smb2transport.c
> @@ -135,11 +135,10 @@ smb2_find_smb_ses(struct smb2_hdr *smb2hdr, struct TCP_Server_Info *server)
>  int
>  smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>  {
> -       int i, rc;
> +       int rc;
>         unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
>         unsigned char *sigptr = smb2_signature;
>         struct kvec *iov = rqst->rq_iov;
> -       int n_vec = rqst->rq_nvec;
>         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
>         struct cifs_ses *ses;
>
> @@ -171,53 +170,11 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>                 return rc;
>         }
>
> -       for (i = 0; i < n_vec; i++) {
> -               if (iov[i].iov_len == 0)
> -                       continue;
> -               if (iov[i].iov_base == NULL) {
> -                       cifs_dbg(VFS, "null iovec entry\n");
> -                       return -EIO;
> -               }
> -               /*
> -                * The first entry includes a length field (which does not get
> -                * signed that occupies the first 4 bytes before the header).
> -                */
> -               if (i == 0) {
> -                       if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
> -                               break; /* nothing to sign or corrupt header */
> -                       rc =
> -                       crypto_shash_update(
> -                               &server->secmech.sdeschmacsha256->shash,
> -                               iov[i].iov_base + 4, iov[i].iov_len - 4);
> -               } else {
> -                       rc =
> -                       crypto_shash_update(
> -                               &server->secmech.sdeschmacsha256->shash,
> -                               iov[i].iov_base, iov[i].iov_len);
> -               }
> -               if (rc) {
> -                       cifs_dbg(VFS, "%s: Could not update with payload\n",
> -                                __func__);
> -                       return rc;
> -               }
> -       }
> -
> -       /* now hash over the rq_pages array */
> -       for (i = 0; i < rqst->rq_npages; i++) {
> -               struct kvec p_iov;
> -
> -               cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> -               crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
> -                                       p_iov.iov_base, p_iov.iov_len);
> -               kunmap(rqst->rq_pages[i]);
> -       }
> -
> -       rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
> -                               sigptr);
> -       if (rc)
> -               cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
> +       rc = __cifs_calc_signature(rqst, server, sigptr,
> +               &server->secmech.sdeschmacsha256->shash);
>
> -       memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
> +       if (!rc)
> +               memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
>
>         return rc;
>  }
> @@ -395,12 +352,10 @@ generate_smb311signingkey(struct cifs_ses *ses)
>  int
>  smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>  {
> -       int i;
>         int rc = 0;
>         unsigned char smb3_signature[SMB2_CMACAES_SIZE];
>         unsigned char *sigptr = smb3_signature;
>         struct kvec *iov = rqst->rq_iov;
> -       int n_vec = rqst->rq_nvec;
>         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
>         struct cifs_ses *ses;
>
> @@ -431,54 +386,12 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>                 cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
>                 return rc;
>         }
> +
> +       rc = __cifs_calc_signature(rqst, server, sigptr,
> +                                  &server->secmech.sdesccmacaes->shash);
>
> -       for (i = 0; i < n_vec; i++) {
> -               if (iov[i].iov_len == 0)
> -                       continue;
> -               if (iov[i].iov_base == NULL) {
> -                       cifs_dbg(VFS, "null iovec entry");
> -                       return -EIO;
> -               }
> -               /*
> -                * The first entry includes a length field (which does not get
> -                * signed that occupies the first 4 bytes before the header).
> -                */
> -               if (i == 0) {
> -                       if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
> -                               break; /* nothing to sign or corrupt header */
> -                       rc =
> -                       crypto_shash_update(
> -                               &server->secmech.sdesccmacaes->shash,
> -                               iov[i].iov_base + 4, iov[i].iov_len - 4);
> -               } else {
> -                       rc =
> -                       crypto_shash_update(
> -                               &server->secmech.sdesccmacaes->shash,
> -                               iov[i].iov_base, iov[i].iov_len);
> -               }
> -               if (rc) {
> -                       cifs_dbg(VFS, "%s: Couldn't update cmac aes with payload\n",
> -                                                       __func__);
> -                       return rc;
> -               }
> -       }
> -
> -       /* now hash over the rq_pages array */
> -       for (i = 0; i < rqst->rq_npages; i++) {
> -               struct kvec p_iov;
> -
> -               cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> -               crypto_shash_update(&server->secmech.sdesccmacaes->shash,
> -                                       p_iov.iov_base, p_iov.iov_len);
> -               kunmap(rqst->rq_pages[i]);
> -       }
> -
> -       rc = crypto_shash_final(&server->secmech.sdesccmacaes->shash,
> -                                               sigptr);
> -       if (rc)
> -               cifs_dbg(VFS, "%s: Could not generate cmac aes\n", __func__);
> -
> -       memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
> +       if (!rc)
> +               memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
>
>         return rc;
>  }
> --
> 2.8.0.rc3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
> the body of a message to [hidden email]
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Re: [PATCH 5/6] cifs_readv_receive: use cifs_read_from_socket()

Jeff Layton-3
In reply to this post by Al Viro-3
On Sat, 2016-04-09 at 21:52 +0100, Al Viro wrote:

> Signed-off-by: Al Viro <[hidden email]>
> ---
>  fs/cifs/cifssmb.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> index 76fcb50..3da077a 100644
> --- a/fs/cifs/cifssmb.c
> +++ b/fs/cifs/cifssmb.c
> @@ -1447,10 +1447,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
>   len = min_t(unsigned int, buflen, server->vals->read_rsp_size) -
>   HEADER_SIZE(server) + 1;
>  
> - rdata->iov.iov_base = buf + HEADER_SIZE(server) - 1;
> - rdata->iov.iov_len = len;
> -
> - length = cifs_readv_from_socket(server, &rdata->iov, 1, len);
> + length = cifs_read_from_socket(server,
> +        buf + HEADER_SIZE(server) - 1, len);
>   if (length < 0)
>   return length;
>   server->total_read += length;
> @@ -1502,9 +1500,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
>   len = data_offset - server->total_read;
>   if (len > 0) {
>   /* read any junk before data into the rest of smallbuf */
> - rdata->iov.iov_base = buf + server->total_read;
> - rdata->iov.iov_len = len;
> - length = cifs_readv_from_socket(server, &rdata->iov, 1, len);
> + length = cifs_read_from_socket(server,
> +        buf + server->total_read, len);
>   if (length < 0)
>   return length;
>   server->total_read += length;

This one is orthogonal to the rest. Looks good though.

Reviewed-by: Jeff Layton <[hidden email]>
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Re: [PATCH 1/6] [net] drop 'size' argument of sock_recvmsg()

Jeff Layton-3
In reply to this post by Al Viro-3
On Sat, 2016-04-09 at 21:50 +0100, Al Viro wrote:

> all callers have it equal to msg_data_left(msg).
>
> Signed-off-by: Al Viro <[hidden email]>
> ---
>  drivers/target/iscsi/iscsi_target_util.c |  5 ++---
>  include/linux/net.h                      |  3 +--
>  net/socket.c                             | 23 ++++++++++-------------
>  3 files changed, 13 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
> index 428b0d9..5772038 100644
> --- a/drivers/target/iscsi/iscsi_target_util.c
> +++ b/drivers/target/iscsi/iscsi_target_util.c
> @@ -1283,9 +1283,8 @@ static int iscsit_do_rx_data(
>   iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC,
>         count->iov, count->iov_count, data);
>  
> - while (total_rx < data) {
> - rx_loop = sock_recvmsg(conn->sock, &msg,
> -       (data - total_rx), MSG_WAITALL);
> + while (msg_data_left(&msg)) {
> + rx_loop = sock_recvmsg(conn->sock, &msg, MSG_WAITALL);
>   if (rx_loop <= 0) {
>   pr_debug("rx_loop: %d total_rx: %d\n",
>   rx_loop, total_rx);
> diff --git a/include/linux/net.h b/include/linux/net.h
> index 49175e4..72c1e06 100644
> --- a/include/linux/net.h
> +++ b/include/linux/net.h
> @@ -218,8 +218,7 @@ int sock_create_lite(int family, int type, int proto, struct socket **res);
>  struct socket *sock_alloc(void);
>  void sock_release(struct socket *sock);
>  int sock_sendmsg(struct socket *sock, struct msghdr *msg);
> -int sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
> -  int flags);
> +int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags);
>  struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname);
>  struct socket *sockfd_lookup(int fd, int *err);
>  struct socket *sock_from_file(struct file *file, int *err);
> diff --git a/net/socket.c b/net/socket.c
> index 5f77a8e..956426e3 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -709,17 +709,16 @@ void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
>  EXPORT_SYMBOL_GPL(__sock_recv_ts_and_drops);
>  
>  static inline int sock_recvmsg_nosec(struct socket *sock, struct msghdr *msg,
> -      size_t size, int flags)
> +      int flags)
>  {
> - return sock->ops->recvmsg(sock, msg, size, flags);
> + return sock->ops->recvmsg(sock, msg, msg_data_left(msg), flags);
>  }
>  
> -int sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
> -  int flags)
> +int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags)
>  {
> - int err = security_socket_recvmsg(sock, msg, size, flags);
> + int err = security_socket_recvmsg(sock, msg, msg_data_left(msg), flags);
>  
> - return err ?: sock_recvmsg_nosec(sock, msg, size, flags);
> + return err ?: sock_recvmsg_nosec(sock, msg, flags);
>  }
>  EXPORT_SYMBOL(sock_recvmsg);
>  
> @@ -746,7 +745,7 @@ int kernel_recvmsg(struct socket *sock, struct msghdr *msg,
>  
>   iov_iter_kvec(&msg->msg_iter, READ | ITER_KVEC, vec, num, size);
>   set_fs(KERNEL_DS);
> - result = sock_recvmsg(sock, msg, size, flags);
> + result = sock_recvmsg(sock, msg, flags);
>   set_fs(oldfs);
>   return result;
>  }
> @@ -796,7 +795,7 @@ static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to)
>   if (!iov_iter_count(to)) /* Match SYS5 behaviour */
>   return 0;
>  
> - res = sock_recvmsg(sock, &msg, iov_iter_count(to), msg.msg_flags);
> + res = sock_recvmsg(sock, &msg, msg.msg_flags);
>   *to = msg.msg_iter;
>   return res;
>  }
> @@ -1696,7 +1695,7 @@ SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size,
>   msg.msg_iocb = NULL;
>   if (sock->file->f_flags & O_NONBLOCK)
>   flags |= MSG_DONTWAIT;
> - err = sock_recvmsg(sock, &msg, iov_iter_count(&msg.msg_iter), flags);
> + err = sock_recvmsg(sock, &msg, flags);
>  
>   if (err >= 0 && addr != NULL) {
>   err2 = move_addr_to_user(&address,
> @@ -2073,7 +2072,7 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
>   struct iovec iovstack[UIO_FASTIOV];
>   struct iovec *iov = iovstack;
>   unsigned long cmsg_ptr;
> - int total_len, len;
> + int len;
>   ssize_t err;
>  
>   /* kernel mode address */
> @@ -2091,7 +2090,6 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
>   err = copy_msghdr_from_user(msg_sys, msg, &uaddr, &iov);
>   if (err < 0)
>   return err;
> - total_len = iov_iter_count(&msg_sys->msg_iter);
>  
>   cmsg_ptr = (unsigned long)msg_sys->msg_control;
>   msg_sys->msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
> @@ -2101,8 +2099,7 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
>  
>   if (sock->file->f_flags & O_NONBLOCK)
>   flags |= MSG_DONTWAIT;
> - err = (nosec ? sock_recvmsg_nosec : sock_recvmsg)(sock, msg_sys,
> -   total_len, flags);
> + err = (nosec ? sock_recvmsg_nosec : sock_recvmsg)(sock, msg_sys, flags);
>   if (err < 0)
>   goto out_freeiov;
>   len = err;

Looks good. Assuming that the corresponding change to sock_recvmsg is
merged.

Reviewed-by: Jeff Layton <[hidden email]>
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Re: [PATCH 2/6] cifs: merge the hash calculation helpers

Jeff Layton-3
In reply to this post by Al Viro-3
On Sat, 2016-04-09 at 21:50 +0100, Al Viro wrote:

> three practically identical copies...
>
> Signed-off-by: Al Viro <[hidden email]>
> ---
>  fs/cifs/cifsencrypt.c   |  97 ++++++++++++++++++++++++-------------------
>  fs/cifs/cifsproto.h     |   3 ++
>  fs/cifs/smb2transport.c | 107 +++++-------------------------------------------
>  3 files changed, 67 insertions(+), 140 deletions(-)
>
> diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
> index 4897dac..6aeb8d4 100644
> --- a/fs/cifs/cifsencrypt.c
> +++ b/fs/cifs/cifsencrypt.c
> @@ -66,45 +66,15 @@ cifs_crypto_shash_md5_allocate(struct TCP_Server_Info *server)
>   return 0;
>  }
>  
> -/*
> - * Calculate and return the CIFS signature based on the mac key and SMB PDU.
> - * The 16 byte signature must be allocated by the caller. Note we only use the
> - * 1st eight bytes and that the smb header signature field on input contains
> - * the sequence number before this function is called. Also, this function
> - * should be called with the server->srv_mutex held.
> - */
> -static int cifs_calc_signature(struct smb_rqst *rqst,
> - struct TCP_Server_Info *server, char *signature)
> +int __cifs_calc_signature(struct smb_rqst *rqst,
> + struct TCP_Server_Info *server, char *signature,
> + struct shash_desc *shash)
>  {
>   int i;
>   int rc;
>   struct kvec *iov = rqst->rq_iov;
>   int n_vec = rqst->rq_nvec;
>  
> - if (iov == NULL || signature == NULL || server == NULL)
> - return -EINVAL;
> -
> - if (!server->secmech.sdescmd5) {
> - rc = cifs_crypto_shash_md5_allocate(server);
> - if (rc) {
> - cifs_dbg(VFS, "%s: Can't alloc md5 crypto\n", __func__);
> - return -1;
> - }
> - }
> -
> - rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
> - if (rc) {
> - cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
> - return rc;
> - }
> -
> - rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
> - server->session_key.response, server->session_key.len);
> - if (rc) {
> - cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
> - return rc;
> - }
> -
>   for (i = 0; i < n_vec; i++) {
>   if (iov[i].iov_len == 0)
>   continue;
> @@ -117,12 +87,10 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
>   if (i == 0) {
>   if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
>   break; /* nothing to sign or corrupt header */
> - rc =
> - crypto_shash_update(&server->secmech.sdescmd5->shash,
> + rc = crypto_shash_update(shash,
>   iov[i].iov_base + 4, iov[i].iov_len - 4);
>   } else {
> - rc =
> - crypto_shash_update(&server->secmech.sdescmd5->shash,
> + rc = crypto_shash_update(shash,
>   iov[i].iov_base, iov[i].iov_len);
>   }
>   if (rc) {
> @@ -134,21 +102,64 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
>  
>   /* now hash over the rq_pages array */
>   for (i = 0; i < rqst->rq_npages; i++) {
> - struct kvec p_iov;
> + void *kaddr = kmap(rqst->rq_pages[i]);
> + size_t len = rqst->rq_pagesz;
> +
> + if (i == rqst->rq_npages - 1)
> + len = rqst->rq_tailsz;
> +
> + crypto_shash_update(shash, kaddr, len);
>  
> - cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> - crypto_shash_update(&server->secmech.sdescmd5->shash,
> - p_iov.iov_base, p_iov.iov_len);
>   kunmap(rqst->rq_pages[i]);
>   }
>  
> - rc = crypto_shash_final(&server->secmech.sdescmd5->shash, signature);
> + rc = crypto_shash_final(shash, signature);
>   if (rc)
> - cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
> + cifs_dbg(VFS, "%s: Could not generate hash\n", __func__);
>  
>   return rc;
>  }
>  
> +/*
> + * Calculate and return the CIFS signature based on the mac key and SMB PDU.
> + * The 16 byte signature must be allocated by the caller. Note we only use the
> + * 1st eight bytes and that the smb header signature field on input contains
> + * the sequence number before this function is called. Also, this function
> + * should be called with the server->srv_mutex held.
> + */
> +static int cifs_calc_signature(struct smb_rqst *rqst,
> + struct TCP_Server_Info *server, char *signature)
> +{
> + int rc;
> +
> + if (!rqst->rq_iov || !signature || !server)
> + return -EINVAL;
> +
> + if (!server->secmech.sdescmd5) {
> + rc = cifs_crypto_shash_md5_allocate(server);
> + if (rc) {
> + cifs_dbg(VFS, "%s: Can't alloc md5 crypto\n", __func__);
> + return -1;
> + }
> + }
> +
> + rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
> + if (rc) {
> + cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
> + return rc;
> + }
> +
> + rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
> + server->session_key.response, server->session_key.len);
> + if (rc) {
> + cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
> + return rc;
> + }
> +
> + return __cifs_calc_signature(rqst, server, signature,
> +      &server->secmech.sdescmd5->shash);
> +}
> +
>  /* must be called with server->srv_mutex held */
>  int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server,
>      __u32 *pexpected_response_sequence_number)
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index eed7ff5..d9b4f44 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -512,4 +512,7 @@ int cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
>      struct cifs_sb_info *cifs_sb,
>      const unsigned char *path, char *pbuf,
>      unsigned int *pbytes_written);
> +int __cifs_calc_signature(struct smb_rqst *rqst,
> + struct TCP_Server_Info *server, char *signature,
> + struct shash_desc *shash);
>  #endif /* _CIFSPROTO_H */
> diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
> index 8732a43..bc9a7b6 100644
> --- a/fs/cifs/smb2transport.c
> +++ b/fs/cifs/smb2transport.c
> @@ -135,11 +135,10 @@ smb2_find_smb_ses(struct smb2_hdr *smb2hdr, struct TCP_Server_Info *server)
>  int
>  smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>  {
> - int i, rc;
> + int rc;
>   unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
>   unsigned char *sigptr = smb2_signature;
>   struct kvec *iov = rqst->rq_iov;
> - int n_vec = rqst->rq_nvec;
>   struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
>   struct cifs_ses *ses;
>  
> @@ -171,53 +170,11 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>   return rc;
>   }
>  
> - for (i = 0; i < n_vec; i++) {
> - if (iov[i].iov_len == 0)
> - continue;
> - if (iov[i].iov_base == NULL) {
> - cifs_dbg(VFS, "null iovec entry\n");
> - return -EIO;
> - }
> - /*
> -  * The first entry includes a length field (which does not get
> -  * signed that occupies the first 4 bytes before the header).
> -  */
> - if (i == 0) {
> - if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
> - break; /* nothing to sign or corrupt header */
> - rc =
> - crypto_shash_update(
> - &server->secmech.sdeschmacsha256->shash,
> - iov[i].iov_base + 4, iov[i].iov_len - 4);
> - } else {
> - rc =
> - crypto_shash_update(
> - &server->secmech.sdeschmacsha256->shash,
> - iov[i].iov_base, iov[i].iov_len);
> - }
> - if (rc) {
> - cifs_dbg(VFS, "%s: Could not update with payload\n",
> -  __func__);
> - return rc;
> - }
> - }
> -
> - /* now hash over the rq_pages array */
> - for (i = 0; i < rqst->rq_npages; i++) {
> - struct kvec p_iov;
> -
> - cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> - crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
> - p_iov.iov_base, p_iov.iov_len);
> - kunmap(rqst->rq_pages[i]);
> - }
> -
> - rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
> - sigptr);
> - if (rc)
> - cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
> + rc = __cifs_calc_signature(rqst, server, sigptr,
> + &server->secmech.sdeschmacsha256->shash);
>  
> - memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
> + if (!rc)
> + memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
>  
>   return rc;
>  }
> @@ -395,12 +352,10 @@ generate_smb311signingkey(struct cifs_ses *ses)
>  int
>  smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>  {
> - int i;
>   int rc = 0;
>   unsigned char smb3_signature[SMB2_CMACAES_SIZE];
>   unsigned char *sigptr = smb3_signature;
>   struct kvec *iov = rqst->rq_iov;
> - int n_vec = rqst->rq_nvec;
>   struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
>   struct cifs_ses *ses;
>  
> @@ -431,54 +386,12 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>   cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
>   return rc;
>   }
> +
> + rc = __cifs_calc_signature(rqst, server, sigptr,
> +    &server->secmech.sdesccmacaes->shash);
>  
> - for (i = 0; i < n_vec; i++) {
> - if (iov[i].iov_len == 0)
> - continue;
> - if (iov[i].iov_base == NULL) {
> - cifs_dbg(VFS, "null iovec entry");
> - return -EIO;
> - }
> - /*
> -  * The first entry includes a length field (which does not get
> -  * signed that occupies the first 4 bytes before the header).
> -  */
> - if (i == 0) {
> - if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
> - break; /* nothing to sign or corrupt header */
> - rc =
> - crypto_shash_update(
> - &server->secmech.sdesccmacaes->shash,
> - iov[i].iov_base + 4, iov[i].iov_len - 4);
> - } else {
> - rc =
> - crypto_shash_update(
> - &server->secmech.sdesccmacaes->shash,
> - iov[i].iov_base, iov[i].iov_len);
> - }
> - if (rc) {
> - cifs_dbg(VFS, "%s: Couldn't update cmac aes with payload\n",
> - __func__);
> - return rc;
> - }
> - }
> -
> - /* now hash over the rq_pages array */
> - for (i = 0; i < rqst->rq_npages; i++) {
> - struct kvec p_iov;
> -
> - cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> - crypto_shash_update(&server->secmech.sdesccmacaes->shash,
> - p_iov.iov_base, p_iov.iov_len);
> - kunmap(rqst->rq_pages[i]);
> - }
> -
> - rc = crypto_shash_final(&server->secmech.sdesccmacaes->shash,
> - sigptr);
> - if (rc)
> - cifs_dbg(VFS, "%s: Could not generate cmac aes\n", __func__);
> -
> - memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
> + if (!rc)
> + memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
>  
>   return rc;
>  }

Nice. Long overdue cleanup.

Reviewed-by: Jeff Layton <[hidden email]>
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Re: [PATCH 3/6] cifs: quit playing games with draining iovecs

Jeff Layton-3
In reply to this post by Al Viro-3
On Sat, 2016-04-09 at 21:51 +0100, Al Viro wrote:

> ... and use ITER_BVEC for the page part of request to send
>
> Signed-off-by: Al Viro <[hidden email]>
> ---
>  fs/cifs/cifsproto.h |   2 -
>  fs/cifs/transport.c | 141 +++++++++++++++---------------------------
> ----------
>  2 files changed, 41 insertions(+), 102 deletions(-)
>
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index d9b4f44..7d5f53a 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -37,8 +37,6 @@ extern void cifs_buf_release(void *);
>  extern struct smb_hdr *cifs_small_buf_get(void);
>  extern void cifs_small_buf_release(void *);
>  extern void free_rsp_buf(int, void *);
> -extern void cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned
> int idx,
> - struct kvec *iov);
>  extern int smb_send(struct TCP_Server_Info *, struct smb_hdr *,
>   unsigned int /* length */);
>  extern unsigned int _get_xid(void);
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index 87abe8e..206a597 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -124,41 +124,32 @@ cifs_delete_mid(struct mid_q_entry *mid)
>  /*
>   * smb_send_kvec - send an array of kvecs to the server
>   * @server: Server to send the data to
> - * @iov: Pointer to array of kvecs
> - * @n_vec: length of kvec array
> + * @smb_msg: Message to send
>   * @sent: amount of data sent on socket is stored here
>   *
>   * Our basic "send data to server" function. Should be called with
> srv_mutex
>   * held. The caller is responsible for handling the results.
>   */
>  static int
> -smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov,
> size_t n_vec,
> - size_t *sent)
> +smb_send_kvec(struct TCP_Server_Info *server, struct msghdr
> *smb_msg,
> +       size_t *sent)
>  {
>   int rc = 0;
> - int i = 0;
> - struct msghdr smb_msg;
> - unsigned int remaining;
> - size_t first_vec = 0;
> + int retries = 0;
>   struct socket *ssocket = server->ssocket;
>  
>   *sent = 0;
>  
> - smb_msg.msg_name = (struct sockaddr *) &server->dstaddr;
> - smb_msg.msg_namelen = sizeof(struct sockaddr);
> - smb_msg.msg_control = NULL;
> - smb_msg.msg_controllen = 0;
> + smb_msg->msg_name = (struct sockaddr *) &server->dstaddr;
> + smb_msg->msg_namelen = sizeof(struct sockaddr);
> + smb_msg->msg_control = NULL;
> + smb_msg->msg_controllen = 0;
>   if (server->noblocksnd)
> - smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
> + smb_msg->msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
>   else
> - smb_msg.msg_flags = MSG_NOSIGNAL;
> -
> - remaining = 0;
> - for (i = 0; i < n_vec; i++)
> - remaining += iov[i].iov_len;
> + smb_msg->msg_flags = MSG_NOSIGNAL;
>  
> - i = 0;
> - while (remaining) {
> + while (msg_data_left(smb_msg)) {
>   /*
>    * If blocking send, we try 3 times, since each can
> block
>    * for 5 seconds. For nonblocking  we have to try
> more
> @@ -177,35 +168,21 @@ smb_send_kvec(struct TCP_Server_Info *server,
> struct kvec *iov, size_t n_vec,
>    * after the retries we will kill the socket and
>    * reconnect which may clear the network problem.
>    */
> - rc = kernel_sendmsg(ssocket, &smb_msg,
> &iov[first_vec],
> -     n_vec - first_vec, remaining);
> + rc = sock_sendmsg(ssocket, smb_msg);
>   if (rc == -EAGAIN) {
> - i++;
> - if (i >= 14 || (!server->noblocksnd && (i >
> 2))) {
> + retries++;
> + if (retries >= 14 ||
> +     (!server->noblocksnd && (retries > 2)))
> {
>   cifs_dbg(VFS, "sends on sock %p
> stuck for 15 seconds\n",
>    ssocket);
> - rc = -EAGAIN;
> - break;
> + return -EAGAIN;
>   }
> - msleep(1 << i);
> + msleep(1 << retries);
>   continue;
>   }
>  
>   if (rc < 0)
> - break;
> -
> - /* send was at least partially successful */
> - *sent += rc;
> -
> - if (rc == remaining) {
> - remaining = 0;
> - break;
> - }
> -
> - if (rc > remaining) {
> - cifs_dbg(VFS, "sent %d requested %d\n", rc,
> remaining);
> - break;
> - }
> + return rc;
>  
>   if (rc == 0) {
>   /* should never happen, letting socket clear
> before
> @@ -215,59 +192,11 @@ smb_send_kvec(struct TCP_Server_Info *server,
> struct kvec *iov, size_t n_vec,
>   continue;
>   }
>  
> - remaining -= rc;
> -
> - /* the line below resets i */
> - for (i = first_vec; i < n_vec; i++) {
> - if (iov[i].iov_len) {
> - if (rc > iov[i].iov_len) {
> - rc -= iov[i].iov_len;
> - iov[i].iov_len = 0;
> - } else {
> - iov[i].iov_base += rc;
> - iov[i].iov_len -= rc;
> - first_vec = i;
> - break;
> - }
> - }
> - }
> -
> - i = 0; /* in case we get ENOSPC on the next send */
> - rc = 0;
> + /* send was at least partially successful */
> + *sent += rc;
> + retries = 0; /* in case we get ENOSPC on the next
> send */
>   }
> - return rc;
> -}
> -
> -/**
> - * rqst_page_to_kvec - Turn a slot in the smb_rqst page array into a
> kvec
> - * @rqst: pointer to smb_rqst
> - * @idx: index into the array of the page
> - * @iov: pointer to struct kvec that will hold the result
> - *
> - * Helper function to convert a slot in the rqst->rq_pages array
> into a kvec.
> - * The page will be kmapped and the address placed into iov_base.
> The length
> - * will then be adjusted according to the ptailoff.
> - */
> -void
> -cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx,
> - struct kvec *iov)
> -{
> - /*
> -  * FIXME: We could avoid this kmap altogether if we used
> -  * kernel_sendpage instead of kernel_sendmsg. That will only
> -  * work if signing is disabled though as sendpage inlines
> the
> -  * page directly into the fraglist. If userspace modifies
> the
> -  * page after we calculate the signature, then the server
> will
> -  * reject it and may break the connection. kernel_sendmsg
> does
> -  * an extra copy of the data and avoids that issue.
> -  */
> - iov->iov_base = kmap(rqst->rq_pages[idx]);
> -
> - /* if last page, don't send beyond this offset into page */
> - if (idx == (rqst->rq_npages - 1))
> - iov->iov_len = rqst->rq_tailsz;
> - else
> - iov->iov_len = rqst->rq_pagesz;
> + return 0;
>  }
>  
>  static unsigned long
> @@ -299,8 +228,9 @@ smb_send_rqst(struct TCP_Server_Info *server,
> struct smb_rqst *rqst)
>   unsigned int smb_buf_length =
> get_rfc1002_length(iov[0].iov_base);
>   unsigned long send_length;
>   unsigned int i;
> - size_t total_len = 0, sent;
> + size_t total_len = 0, sent, size;
>   struct socket *ssocket = server->ssocket;
> + struct msghdr smb_msg;
>   int val = 1;
>  
>   if (ssocket == NULL)
> @@ -321,7 +251,13 @@ smb_send_rqst(struct TCP_Server_Info *server,
> struct smb_rqst *rqst)
>   kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
>   (char *)&val, sizeof(val));
>  
> - rc = smb_send_kvec(server, iov, n_vec, &sent);
> + size = 0;
> + for (i = 0; i < n_vec; i++)
> + size += iov[i].iov_len;
> +
> + iov_iter_kvec(&smb_msg.msg_iter, WRITE | ITER_KVEC, iov,
> n_vec, size);
> +
> + rc = smb_send_kvec(server, &smb_msg, &sent);
>   if (rc < 0)
>   goto uncork;
>  
> @@ -329,11 +265,16 @@ smb_send_rqst(struct TCP_Server_Info *server,
> struct smb_rqst *rqst)
>  
>   /* now walk the page array and send each page in it */
>   for (i = 0; i < rqst->rq_npages; i++) {
> - struct kvec p_iov;
> -
> - cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> - rc = smb_send_kvec(server, &p_iov, 1, &sent);
> - kunmap(rqst->rq_pages[i]);
> + size_t len = i == rqst->rq_npages - 1
> + ? rqst->rq_tailsz
> + : rqst->rq_pagesz;
> + struct bio_vec bvec = {
> + .bv_page = rqst->rq_pages[i],
> + .bv_len = len
> + };
> + iov_iter_bvec(&smb_msg.msg_iter, WRITE | ITER_BVEC,
> +       &bvec, 1, len);
> + rc = smb_send_kvec(server, &smb_msg, &sent);
>   if (rc < 0)
>   break;
>  

What's the advantage of using iov_iter_bvec over iov_iter_kvec ?

That said...

Acked-by: Jeff Layton <[hidden email]>
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Re: [PATCH 4/6] cifs: no need to wank with copying and advancing iovec on recvmsg side either

Jeff Layton-3
In reply to this post by Al Viro-3
On Sat, 2016-04-09 at 21:52 +0100, Al Viro wrote:

> Signed-off-by: Al Viro <[hidden email]>
> ---
>  fs/cifs/cifsglob.h |  2 --
>  fs/cifs/connect.c  | 72 ++++--------------------------------------------------
>  2 files changed, 5 insertions(+), 69 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index d21da9f..df03c5e 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -615,8 +615,6 @@ struct TCP_Server_Info {
>   bool sec_mskerberos; /* supports legacy MS Kerberos */
>   bool large_buf; /* is current buffer large? */
>   struct delayed_work echo; /* echo ping workqueue job */
> - struct kvec *iov; /* reusable kvec array for receives */
> - unsigned int nr_iov; /* number of kvecs in array */
>   char *smallbuf; /* pointer to current "small" buffer */
>   char *bigbuf; /* pointer to current "big" buffer */
>   unsigned int total_read; /* total amount of data read in this pass */
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index a763cd3..eb42665 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -501,77 +501,20 @@ server_unresponsive(struct TCP_Server_Info *server)
>   return false;
>  }
>  
> -/*
> - * kvec_array_init - clone a kvec array, and advance into it
> - * @new: pointer to memory for cloned array
> - * @iov: pointer to original array
> - * @nr_segs: number of members in original array
> - * @bytes: number of bytes to advance into the cloned array
> - *
> - * This function will copy the array provided in iov to a section of memory
> - * and advance the specified number of bytes into the new array. It returns
> - * the number of segments in the new array. "new" must be at least as big as
> - * the original iov array.
> - */
> -static unsigned int
> -kvec_array_init(struct kvec *new, struct kvec *iov, unsigned int nr_segs,
> - size_t bytes)
> -{
> - size_t base = 0;
> -
> - while (bytes || !iov->iov_len) {
> - int copy = min(bytes, iov->iov_len);
> -
> - bytes -= copy;
> - base += copy;
> - if (iov->iov_len == base) {
> - iov++;
> - nr_segs--;
> - base = 0;
> - }
> - }
> - memcpy(new, iov, sizeof(*iov) * nr_segs);
> - new->iov_base += base;
> - new->iov_len -= base;
> - return nr_segs;
> -}
> -
> -static struct kvec *
> -get_server_iovec(struct TCP_Server_Info *server, unsigned int nr_segs)
> -{
> - struct kvec *new_iov;
> -
> - if (server->iov && nr_segs <= server->nr_iov)
> - return server->iov;
> -
> - /* not big enough -- allocate a new one and release the old */
> - new_iov = kmalloc(sizeof(*new_iov) * nr_segs, GFP_NOFS);
> - if (new_iov) {
> - kfree(server->iov);
> - server->iov = new_iov;
> - server->nr_iov = nr_segs;
> - }
> - return new_iov;
> -}
> -
>  int
>  cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
>          unsigned int nr_segs, unsigned int to_read)
>  {
>   int length = 0;
>   int total_read;
> - unsigned int segs;
>   struct msghdr smb_msg;
> - struct kvec *iov;
> -
> - iov = get_server_iovec(server, nr_segs);
> - if (!iov)
> - return -ENOMEM;
>  
>   smb_msg.msg_control = NULL;
>   smb_msg.msg_controllen = 0;
> + iov_iter_kvec(&smb_msg.msg_iter, READ | ITER_KVEC,
> +       iov_orig, nr_segs, to_read);
>  
> - for (total_read = 0; to_read; total_read += length, to_read -= length) {
> + for (total_read = 0; msg_data_left(&smb_msg); total_read += length) {
>   try_to_freeze();
>  
>   if (server_unresponsive(server)) {
> @@ -579,10 +522,7 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
>   break;
>   }
>  
> - segs = kvec_array_init(iov, iov_orig, nr_segs, total_read);
> -
> - length = kernel_recvmsg(server->ssocket, &smb_msg,
> - iov, segs, to_read, 0);
> + length = sock_recvmsg(server->ssocket, &smb_msg, 0);
>  
>   if (server->tcpStatus == CifsExiting) {
>   total_read = -ESHUTDOWN;
> @@ -603,8 +543,7 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
>   length = 0;
>   continue;
>   } else if (length <= 0) {
> - cifs_dbg(FYI, "Received no data or error: expecting %d\n"
> -  "got %d", to_read, length);
> + cifs_dbg(FYI, "Received no data or error: %d\n", length);
>   cifs_reconnect(server);
>   total_read = -ECONNABORTED;
>   break;
> @@ -783,7 +722,6 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server)
>   }
>  
>   kfree(server->hostname);
> - kfree(server->iov);
>   kfree(server);
>  
>   length = atomic_dec_return(&tcpSesAllocCount);

Good riddance.

Reviewed-by: Jeff Layton <[hidden email]>
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Re: [PATCH 6/6] cifs: don't bother with kmap on read_pages side

Jeff Layton-3
In reply to this post by Al Viro-3
On Sat, 2016-04-09 at 21:53 +0100, Al Viro wrote:

> just do ITER_BVEC recvmsg
>
> Signed-off-by: Al Viro <[hidden email]>
> ---
>  fs/cifs/cifsproto.h |  7 +++---
>  fs/cifs/connect.c   | 65 ++++++++++++++++++++++++++++-------------------------
>  fs/cifs/file.c      | 53 ++++++++++++++-----------------------------
>  3 files changed, 55 insertions(+), 70 deletions(-)
>
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index 7d5f53a..0f9a6bc 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -179,10 +179,9 @@ extern int set_cifs_acl(struct cifs_ntsd *, __u32, struct inode *,
>  
>  extern void dequeue_mid(struct mid_q_entry *mid, bool malformed);
>  extern int cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
> -      unsigned int to_read);
> -extern int cifs_readv_from_socket(struct TCP_Server_Info *server,
> - struct kvec *iov_orig, unsigned int nr_segs,
> - unsigned int to_read);
> +          unsigned int to_read);
> +extern int cifs_read_page_from_socket(struct TCP_Server_Info *server,
> +       struct page *page, unsigned int to_read);
>  extern void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
>          struct cifs_sb_info *cifs_sb);
>  extern int cifs_match_super(struct super_block *, void *);
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index eb42665..e33c5e0 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -501,39 +501,34 @@ server_unresponsive(struct TCP_Server_Info *server)
>   return false;
>  }
>  
> -int
> -cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
> -        unsigned int nr_segs, unsigned int to_read)
> +static int
> +cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
>  {
>   int length = 0;
>   int total_read;
> - struct msghdr smb_msg;
>  
> - smb_msg.msg_control = NULL;
> - smb_msg.msg_controllen = 0;
> - iov_iter_kvec(&smb_msg.msg_iter, READ | ITER_KVEC,
> -       iov_orig, nr_segs, to_read);
> + smb_msg->msg_control = NULL;
> + smb_msg->msg_controllen = 0;
>  
> - for (total_read = 0; msg_data_left(&smb_msg); total_read += length) {
> + for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
>   try_to_freeze();
>  
> - if (server_unresponsive(server)) {
> - total_read = -ECONNABORTED;
> - break;
> - }
> + if (server_unresponsive(server))
> + return -ECONNABORTED;
>  
> - length = sock_recvmsg(server->ssocket, &smb_msg, 0);
> + length = sock_recvmsg(server->ssocket, smb_msg, 0);
>  
> - if (server->tcpStatus == CifsExiting) {
> - total_read = -ESHUTDOWN;
> - break;
> - } else if (server->tcpStatus == CifsNeedReconnect) {
> + if (server->tcpStatus == CifsExiting)
> + return -ESHUTDOWN;
> +
> + if (server->tcpStatus == CifsNeedReconnect) {
>   cifs_reconnect(server);
> - total_read = -ECONNABORTED;
> - break;
> - } else if (length == -ERESTARTSYS ||
> -    length == -EAGAIN ||
> -    length == -EINTR) {
> + return -ECONNABORTED;
> + }
> +
> + if (length == -ERESTARTSYS ||
> +     length == -EAGAIN ||
> +     length == -EINTR) {
>   /*
>    * Minimum sleep to prevent looping, allowing socket
>    * to clear and app threads to set tcpStatus
> @@ -542,11 +537,12 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
>   usleep_range(1000, 2000);
>   length = 0;
>   continue;
> - } else if (length <= 0) {
> + }
> +
> + if (length <= 0) {
>   cifs_dbg(FYI, "Received no data or error: %d\n", length);
>   cifs_reconnect(server);
> - total_read = -ECONNABORTED;
> - break;
> + return -ECONNABORTED;
>   }
>   }
>   return total_read;
> @@ -556,12 +552,21 @@ int
>  cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
>         unsigned int to_read)
>  {
> - struct kvec iov;
> + struct msghdr smb_msg;
> + struct kvec iov = {.iov_base = buf, .iov_len = to_read};
> + iov_iter_kvec(&smb_msg.msg_iter, READ | ITER_KVEC, &iov, 1, to_read);
>  
> - iov.iov_base = buf;
> - iov.iov_len = to_read;
> + return cifs_readv_from_socket(server, &smb_msg);
> +}
>  
> - return cifs_readv_from_socket(server, &iov, 1, to_read);
> +int
> +cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
> +       unsigned int to_read)
> +{
> + struct msghdr smb_msg;
> + struct bio_vec bv = {.bv_page = page, .bv_len = to_read};
> + iov_iter_bvec(&smb_msg.msg_iter, READ | ITER_BVEC, &bv, 1, to_read);
> + return cifs_readv_from_socket(server, &smb_msg);
>  }
>  
>  static bool
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index ff882ae..0f71867 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -2855,39 +2855,31 @@ cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
>   int result = 0;
>   unsigned int i;
>   unsigned int nr_pages = rdata->nr_pages;
> - struct kvec iov;
>  
>   rdata->got_bytes = 0;
>   rdata->tailsz = PAGE_SIZE;
>   for (i = 0; i < nr_pages; i++) {
>   struct page *page = rdata->pages[i];
> + size_t n;
>  
> - if (len >= PAGE_SIZE) {
> - /* enough data to fill the page */
> - iov.iov_base = kmap(page);
> - iov.iov_len = PAGE_SIZE;
> - cifs_dbg(FYI, "%u: iov_base=%p iov_len=%zu\n",
> -  i, iov.iov_base, iov.iov_len);
> - len -= PAGE_SIZE;
> - } else if (len > 0) {
> - /* enough for partial page, fill and zero the rest */
> - iov.iov_base = kmap(page);
> - iov.iov_len = len;
> - cifs_dbg(FYI, "%u: iov_base=%p iov_len=%zu\n",
> -  i, iov.iov_base, iov.iov_len);
> - memset(iov.iov_base + len, '\0', PAGE_SIZE - len);
> - rdata->tailsz = len;
> - len = 0;
> - } else {
> + if (len <= 0) {
>   /* no need to hold page hostage */
>   rdata->pages[i] = NULL;
>   rdata->nr_pages--;
>   put_page(page);
>   continue;
>   }
> -
> - result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
> - kunmap(page);
> + n = len;
> + if (len >= PAGE_SIZE) {
> + /* enough data to fill the page */
> + n = PAGE_SIZE;
> + len -= n;
> + } else {
> + zero_user(page, len, PAGE_SIZE - len);
> + rdata->tailsz = len;
> + len = 0;
> + }
> + result = cifs_read_page_from_socket(server, page, n);
>   if (result < 0)
>   break;
>  
> @@ -3303,7 +3295,6 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
>   u64 eof;
>   pgoff_t eof_index;
>   unsigned int nr_pages = rdata->nr_pages;
> - struct kvec iov;
>  
>   /* determine the eof that the server (probably) has */
>   eof = CIFS_I(rdata->mapping->host)->server_eof;
> @@ -3314,23 +3305,14 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
>   rdata->tailsz = PAGE_CACHE_SIZE;
>   for (i = 0; i < nr_pages; i++) {
>   struct page *page = rdata->pages[i];
> + size_t n = PAGE_CACHE_SIZE;
>  
>   if (len >= PAGE_CACHE_SIZE) {
> - /* enough data to fill the page */
> - iov.iov_base = kmap(page);
> - iov.iov_len = PAGE_CACHE_SIZE;
> - cifs_dbg(FYI, "%u: idx=%lu iov_base=%p iov_len=%zu\n",
> -  i, page->index, iov.iov_base, iov.iov_len);
>   len -= PAGE_CACHE_SIZE;
>   } else if (len > 0) {
>   /* enough for partial page, fill and zero the rest */
> - iov.iov_base = kmap(page);
> - iov.iov_len = len;
> - cifs_dbg(FYI, "%u: idx=%lu iov_base=%p iov_len=%zu\n",
> -  i, page->index, iov.iov_base, iov.iov_len);
> - memset(iov.iov_base + len,
> - '\0', PAGE_CACHE_SIZE - len);
> - rdata->tailsz = len;
> + zero_user(page, len, PAGE_CACHE_SIZE - len);
> + n = rdata->tailsz = len;
>   len = 0;
>   } else if (page->index > eof_index) {
>   /*
> @@ -3360,8 +3342,7 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
>   continue;
>   }
>  
> - result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
> - kunmap(page);
> + result = cifs_read_page_from_socket(server, page, n);
>   if (result < 0)
>   break;
>  

Reviewed-by: Jeff Layton <[hidden email]>
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Re: [PATCH 3/6] cifs: quit playing games with draining iovecs

Al Viro-3
In reply to this post by Jeff Layton-3
On Tue, Apr 19, 2016 at 01:53:17PM -0400, Jeff Layton wrote:

> What's the advantage of using iov_iter_bvec over iov_iter_kvec ?

No need to screw with kmap() in the caller; moreover, when it comes to actual
copying it gets away with kmap_atomic() just around the memcpy(), which is
considerably cheaper.
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Re: [RFC][PATCHSET] reduce messing with iovecs in cifs

Steve French-2
In reply to this post by Al Viro-3
Reviewed-by: Steve French <[hidden email]>

Let me know if you want any of them to go in via the cifs tree or
prefer going in through your tree (other than patch 1 which could go
in the net-next tree are you indicated)

On Sat, Apr 9, 2016 at 3:43 PM, Al Viro <[hidden email]> wrote:

>         Now that sendmsg/recvmsg do not mangle iovecs and are capable of
> handling bvec-based ->msg_iter, we can seriously reduce the amount of PITA
> in cifs.  The series below is completely untested, and I would appreciate
> comments/review/testing/etc.
>
> I'll post the individual patches in followups; for those who prefer to use
> git it can be found in
> git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git sendmsg.cifs
>
> 1/6: [net] drop 'size' argument of sock_recvmsg()
>         should go via net-next; does what it says.
>
> 2/6: cifs: merge the hash calculation helpers
>         takes the common parts of {cifs,smb2,smb3}_calc_signature() into a
> common helper.
>
> 3/6: cifs: quit playing games with draining iovecs
>         Switch smb_send_kvec() to passing msghdr (and thus iov_iter) and
> make it use sock_sendmsg() - that allows to avoid draining iovecs, since
> ->msg_iter will be advanced properly and all we need is to keep it around
> between the calls of sock_sendmsg(), rather than reinitializing it on each
> loop iteration.  The same thing allows to get rid of messing with kmap()
> when sending the stuff in ->rq_pages[] - ITER_BVEC will do the right thing.
>
> 4/6: cifs: no need to wank with copying and advancing iovec on recvmsg side either
>         Similar to the previous - use sock_recvmsg() in cifs_readv_from_socket()
> and there's no need to modify iovecs, or allocate a copy especially for
> such modifications, etc.
>
> 5/6: cifs_readv_receive: use cifs_read_from_socket()
>         building a 1-element iovec array for cifs_readv_from_socket() is
> an overkill - simple cifs_read_from_socket() will do just fine.
>
> 6/6: cifs: don't bother with kmap on read_pages side
>         Similar to the other half of 3/6: we can use ITER_BVEC for
> read-into-page case.  Just make cifs_readv_from_socket() take msghdr from
> caller and use a helper that would feed it a bvec-backed ->msg_iter.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
> the body of a message to [hidden email]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



--
Thanks,

Steve