Commit 56851698 authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by James Bottomley
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[SCSI] iscsi: data digest page cache usage fix 



Users can write to a page while we are sending it and making
digest calculations. This ends up causing us to retry the command
when a digest error is later reported. By using sock_no_sendpage
when data digests are calculated we can avoid a lot of (not all but it
helps) the retries becuase sock_no_sendpage is not zero copy.

Signed-off-by: default avatarAlex Aizman <itn780@yahoo.com>
Signed-off-by: default avatarDmitry Yusupov <dmitry_yus@yahoo.com>
Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent 3e97c7e6

drivers/scsi/iscsi_tcp.c

+9 −7
Original line number Diff line number Diff line
@@ -1318,15 +1318,15 @@ iscsi_conn_restore_callbacks(struct iscsi_conn *conn) 
 *	to use tcp_sendmsg().

 */

static inline int

iscsi_send(struct socket *sk, struct iscsi_buf *buf, int size, int flags)

iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags)

{

	struct socket *sk = conn->sock;

	int res;



	if ((int)buf->sg.offset >= 0) {

		int offset = buf->sg.offset + buf->sent;



		/* tcp_sendpage */

		res = sk->ops->sendpage(sk, buf->sg.page, offset, size, flags);

		res = conn->sendpage(sk, buf->sg.page, offset, size, flags);

	} else {

		struct msghdr msg;
@@ -1354,7 +1354,6 @@ iscsi_send(struct socket *sk, struct iscsi_buf *buf, int size, int flags) 
static inline int

iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen)

{

	struct socket *sk = conn->sock;

	int flags = 0; /* MSG_DONTWAIT; */

	int res, size;
@@ -1363,7 +1362,7 @@ iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen) 
	if (buf->sent + size != buf->sg.length || datalen)

		flags |= MSG_MORE;



	res = iscsi_send(sk, buf, size, flags);

	res = iscsi_send(conn, buf, size, flags);

	debug_tcp("sendhdr %d bytes, sent %d res %d\n", size, buf->sent, res);

	if (res >= 0) {

		conn->txdata_octets += res;
@@ -1394,7 +1393,6 @@ static inline int 
iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,

	       int *count, int *sent)

{

	struct socket *sk = conn->sock;

	int flags = 0; /* MSG_DONTWAIT; */

	int res, size;
@@ -1405,7 +1403,7 @@ iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf, 
	if (buf->sent + size != buf->sg.length || *count != size)

		flags |= MSG_MORE;



	res = iscsi_send(sk, buf, size, flags);

	res = iscsi_send(conn, buf, size, flags);

	debug_tcp("sendpage: %d bytes, sent %d left %d sent %d res %d\n",

		  size, buf->sent, *count, *sent, res);

	if (res >= 0) {
@@ -2713,6 +2711,8 @@ iscsi_conn_bind(iscsi_sessionh_t sessionh, iscsi_connh_t connh, 
		 */

		iscsi_conn_set_callbacks(conn);



		conn->sendpage = conn->sock->ops->sendpage;



		/*

		 * set receive state machine into initial state

		 */
@@ -3467,6 +3467,8 @@ iscsi_conn_set_param(iscsi_connh_t connh, enum iscsi_param param, 
			if (conn->data_rx_tfm)

				crypto_free_tfm(conn->data_rx_tfm);

		}

		conn->sendpage = conn->datadgst_en ?

			sock_no_sendpage : conn->sock->ops->sendpage;

		break;

	case ISCSI_PARAM_INITIAL_R2T_EN:

		session->initial_r2t_en = value;

drivers/scsi/iscsi_tcp.h

+2 −0
Original line number Diff line number Diff line
@@ -191,6 +191,8 @@ struct iscsi_conn { 
	uint32_t		sendpage_failures_cnt;

	uint32_t		discontiguous_hdr_cnt;

	uint32_t		eh_abort_cnt;



	ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);

};



struct iscsi_session {

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