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 <viro@xxxxxxxxxxxxxxxxxx>
> ---
> 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 <jlayton@xxxxxxxxxxxxxxx>
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