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Date: Sat, 9 Apr 2016 21:51:29 +0100
From: Al Viro <viro@...IV.linux.org.uk>
To: linux-cifs@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 3/6] cifs: quit playing games with draining iovecs
... and use ITER_BVEC for the page part of request to send
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
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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