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Commit 97bc00b3 authored by Jeff Layton's avatar Jeff Layton Committed by Steve French
Browse files

cifs: teach smb_send_rqst how to handle arrays of pages 



Add code that allows smb_send_rqst to send an array of pages after the
initial kvec array has been sent. For now, we simply kmap the page
array and send it using the standard smb_send_kvec function. Eventually,
we may want to convert this code to use kernel_sendpage under the hood
and avoid the kmap altogether for the page data.

Reviewed-by: default avatarPavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent b8eed283

fs/cifs/transport.c

+54 −2
Original line number Original line Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/delay.h>

#include <linux/delay.h>

#include <linux/freezer.h>

#include <linux/freezer.h>

#include <linux/tcp.h>

#include <linux/tcp.h>

#include <linux/highmem.h>

#include <asm/uaccess.h>

#include <asm/uaccess.h>

#include <asm/processor.h>

#include <asm/processor.h>

#include <linux/mempool.h>

#include <linux/mempool.h>
@@ -240,6 +241,38 @@ smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov, size_t n_vec, 
	return rc;

	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.

 */

static 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;

}



static int

static int

smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)

smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)

{

{
@@ -247,7 +280,8 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst) 
	struct kvec *iov = rqst->rq_iov;

	struct kvec *iov = rqst->rq_iov;

	int n_vec = rqst->rq_nvec;

	int n_vec = rqst->rq_nvec;

	unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);

	unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);

	size_t total_len;

	unsigned int i;

	size_t total_len = 0, sent;

	struct socket *ssocket = server->ssocket;

	struct socket *ssocket = server->ssocket;

	int val = 1;

	int val = 1;
@@ -258,8 +292,26 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst) 
	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,

	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,

				(char *)&val, sizeof(val));

				(char *)&val, sizeof(val));





	rc = smb_send_kvec(server, iov, n_vec, &total_len);

	rc = smb_send_kvec(server, iov, n_vec, &sent);

	if (rc < 0)

		goto uncork;



	total_len += sent;



	/* 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]);

		if (rc < 0)

			break;



		total_len += sent;

	}





uncork:

	/* uncork it */

	/* uncork it */

	val = 0;

	val = 0;

	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,

	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,