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@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2015-11-13 02:36:04 -05:00
parent 16c568efff
commit 3ab3f2a1fe
2 changed files with 41 additions and 102 deletions

View File

@ -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);

View File

@ -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;
smb_msg->msg_flags = MSG_NOSIGNAL;
remaining = 0;
for (i = 0; i < n_vec; i++)
remaining += iov[i].iov_len;
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;