Commit 3219e529 authored by Mike Christie's avatar Mike Christie Committed by James Bottomley
Browse files

[SCSI] iscsi: fix writepsace race 



We can race and misset the suspend bit if iscsi_write_space is
called then iscsi_send returns with a failure indicating
there is no space.

To handle this this patch returns a error upwards allowing xmitworker
to decide if we need to try and transmit again. For the no
write space case xmitworker will not retry, and instead
let iscsi_write_space queue it back up if needed (this relies
on the work queue code to properly requeue us if needed).

Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent 040515f5

drivers/scsi/iscsi_tcp.c

+101 −81
Original line number Diff line number Diff line
@@ -1006,7 +1006,6 @@ iscsi_write_space(struct sock *sk) 


	tcp_conn->old_write_space(sk);

	debug_tcp("iscsi_write_space: cid %d\n", conn->id);

	clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);

	scsi_queue_work(conn->session->host, &conn->xmitwork);

}
@@ -1056,7 +1055,7 @@ iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags) 
{

	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;

	struct socket *sk = tcp_conn->sock;

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

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



	/*

	 * if we got use_sg=0 or are sending something we kmallocd
@@ -1067,10 +1066,22 @@ iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags) 
	 * slab case.

	 */

	if (buf->use_sendmsg)

		return sock_no_sendpage(sk, buf->sg.page, offset, size, flags);

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

	else

		return tcp_conn->sendpage(sk, buf->sg.page, offset, size,

					  flags);

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



	if (res >= 0) {

		conn->txdata_octets += res;

		buf->sent += res;

		return res;

	}



	tcp_conn->sendpage_failures_cnt++;

	if (res == -EAGAIN)

		res = -ENOBUFS;

	else

		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);

	return res;

}



/**
@@ -1085,7 +1096,6 @@ iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags) 
static inline int

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

{

	struct iscsi_tcp_conn *tcp_conn;

	int flags = 0; /* MSG_DONTWAIT; */

	int res, size;
@@ -1097,17 +1107,10 @@ iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen) 
	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;

		buf->sent += res;

		if (size != res)

			return -EAGAIN;

		return 0;

	} else if (res == -EAGAIN) {

		tcp_conn = conn->dd_data;

		tcp_conn->sendpage_failures_cnt++;

		set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);

	} else if (res == -EPIPE)

		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);

	}



	return res;

}
@@ -1126,7 +1129,6 @@ static inline int 
iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,

	       int *count, int *sent)

{

	struct iscsi_tcp_conn *tcp_conn;

	int flags = 0; /* MSG_DONTWAIT; */

	int res, size;
@@ -1141,19 +1143,12 @@ iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf, 
	debug_tcp("sendpage: %d bytes, sent %d left %d sent %d res %d\n",

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

	if (res >= 0) {

		conn->txdata_octets += res;

		buf->sent += res;

		*count -= res;

		*sent += res;

		if (size != res)

			return -EAGAIN;

		return 0;

	} else if (res == -EAGAIN) {

		tcp_conn = conn->dd_data;

		tcp_conn->sendpage_failures_cnt++;

		set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);

	} else if (res == -EPIPE)

		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);

	}



	return res;

}
@@ -1342,6 +1337,7 @@ static int 
iscsi_tcp_mtask_xmit(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask)

{

	struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;

	int rc;



	debug_scsi("mtask deq [cid %d state %x itt 0x%x]\n",

		conn->id, tcp_mtask->xmstate, mtask->itt);
@@ -1355,12 +1351,13 @@ iscsi_tcp_mtask_xmit(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask) 
		    conn->hdrdgst_en)

			iscsi_hdr_digest(conn, &tcp_mtask->headbuf,

					(u8*)tcp_mtask->hdrext);

		if (iscsi_sendhdr(conn, &tcp_mtask->headbuf,

				  mtask->data_count)) {

		rc = iscsi_sendhdr(conn, &tcp_mtask->headbuf,

				   mtask->data_count);

		if (rc) {

			tcp_mtask->xmstate |= XMSTATE_IMM_HDR;

			if (mtask->data_count)

				tcp_mtask->xmstate &= ~XMSTATE_IMM_DATA;

			return -EAGAIN;

			return rc;

		}

	}
@@ -1371,10 +1368,13 @@ iscsi_tcp_mtask_xmit(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask) 
		 * Virtual buffer could be spreaded across multiple pages...

		 */

		do {

			if (iscsi_sendpage(conn, &tcp_mtask->sendbuf,

				   &mtask->data_count, &tcp_mtask->sent)) {

			int rc;



			rc = iscsi_sendpage(conn, &tcp_mtask->sendbuf,

					&mtask->data_count, &tcp_mtask->sent);

			if (rc) {

				tcp_mtask->xmstate |= XMSTATE_IMM_DATA;

				return -EAGAIN;

				return rc;

			}

		} while (mtask->data_count);

	}
@@ -1396,16 +1396,19 @@ static inline int 
handle_xmstate_r_hdr(struct iscsi_conn *conn,

		     struct iscsi_tcp_cmd_task *tcp_ctask)

{

	int rc;



	tcp_ctask->xmstate &= ~XMSTATE_R_HDR;

	if (conn->hdrdgst_en)

		iscsi_hdr_digest(conn, &tcp_ctask->headbuf,

				 (u8*)tcp_ctask->hdrext);

	if (!iscsi_sendhdr(conn, &tcp_ctask->headbuf, 0)) {

	rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, 0);

	if (!rc) {

		BUG_ON(tcp_ctask->xmstate != XMSTATE_IDLE);

		return 0; /* wait for Data-In */

	}

	tcp_ctask->xmstate |= XMSTATE_R_HDR;

	return -EAGAIN;

	return rc;

}



static inline int
@@ -1413,16 +1416,16 @@ handle_xmstate_w_hdr(struct iscsi_conn *conn, 
		     struct iscsi_cmd_task *ctask)

{

	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;

	int rc;



	tcp_ctask->xmstate &= ~XMSTATE_W_HDR;

	if (conn->hdrdgst_en)

		iscsi_hdr_digest(conn, &tcp_ctask->headbuf,

				 (u8*)tcp_ctask->hdrext);

	if (iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->imm_count)) {

	rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->imm_count);

	if (rc)

		tcp_ctask->xmstate |= XMSTATE_W_HDR;

		return -EAGAIN;

	}

	return 0;

	return rc;

}



static inline int
@@ -1430,17 +1433,19 @@ handle_xmstate_data_digest(struct iscsi_conn *conn, 
			   struct iscsi_cmd_task *ctask)

{

	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;

	int rc;



	tcp_ctask->xmstate &= ~XMSTATE_DATA_DIGEST;

	debug_tcp("resent data digest 0x%x\n", tcp_ctask->datadigest);

	if (iscsi_digest_final_send(conn, ctask, &tcp_ctask->immbuf,

				    &tcp_ctask->datadigest, 0)) {

	rc = iscsi_digest_final_send(conn, ctask, &tcp_ctask->immbuf,

				    &tcp_ctask->datadigest, 0);

	if (rc) {

		tcp_ctask->xmstate |= XMSTATE_DATA_DIGEST;

		debug_tcp("resent data digest 0x%x fail!\n",

			  tcp_ctask->datadigest);

		return -EAGAIN;

	}

	return 0;



	return rc;

}



static inline int
@@ -1448,6 +1453,7 @@ handle_xmstate_imm_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
{

	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;

	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;

	int rc;



	BUG_ON(!ctask->imm_count);

	tcp_ctask->xmstate &= ~XMSTATE_IMM_DATA;
@@ -1458,8 +1464,9 @@ handle_xmstate_imm_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
	}



	for (;;) {

		if (iscsi_sendpage(conn, &tcp_ctask->sendbuf, &ctask->imm_count,

				   &tcp_ctask->sent)) {

		rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf,

				   &ctask->imm_count, &tcp_ctask->sent);

		if (rc) {

			tcp_ctask->xmstate |= XMSTATE_IMM_DATA;

			if (conn->datadgst_en) {

				crypto_digest_final(tcp_conn->data_tx_tfm,
@@ -1467,7 +1474,7 @@ handle_xmstate_imm_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
				debug_tcp("tx imm sendpage fail 0x%x\n",

					  tcp_ctask->datadigest);

			}

			return -EAGAIN;

			return rc;

		}

		if (conn->datadgst_en)

			crypto_digest_update(tcp_conn->data_tx_tfm,
@@ -1480,11 +1487,12 @@ handle_xmstate_imm_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
	}



	if (conn->datadgst_en && !(tcp_ctask->xmstate & XMSTATE_W_PAD)) {

		if (iscsi_digest_final_send(conn, ctask, &tcp_ctask->immbuf,

				            &tcp_ctask->immdigest, 1)) {

		rc = iscsi_digest_final_send(conn, ctask, &tcp_ctask->immbuf,

				            &tcp_ctask->immdigest, 1);

		if (rc) {

			debug_tcp("sending imm digest 0x%x fail!\n",

				  tcp_ctask->immdigest);

			return -EAGAIN;

			return rc;

		}

		debug_tcp("sending imm digest 0x%x\n", tcp_ctask->immdigest);

	}
@@ -1497,6 +1505,7 @@ handle_xmstate_uns_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
{

	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;

	struct iscsi_data_task *dtask;

	int rc;



	tcp_ctask->xmstate |= XMSTATE_UNS_DATA;

	if (tcp_ctask->xmstate & XMSTATE_UNS_INIT) {
@@ -1507,10 +1516,12 @@ handle_xmstate_uns_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
					(u8*)dtask->hdrext);

		tcp_ctask->xmstate &= ~XMSTATE_UNS_INIT;

	}

	if (iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->data_count)) {



	rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->data_count);

	if (rc) {

		tcp_ctask->xmstate &= ~XMSTATE_UNS_DATA;

		tcp_ctask->xmstate |= XMSTATE_UNS_HDR;

		return -EAGAIN;

		return rc;

	}



	debug_scsi("uns dout [itt 0x%x dlen %d sent %d]\n",
@@ -1524,6 +1535,7 @@ handle_xmstate_uns_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;

	struct iscsi_data_task *dtask = tcp_ctask->dtask;

	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;

	int rc;



	BUG_ON(!ctask->data_count);

	tcp_ctask->xmstate &= ~XMSTATE_UNS_DATA;
@@ -1536,8 +1548,9 @@ handle_xmstate_uns_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
	for (;;) {

		int start = tcp_ctask->sent;



		if (iscsi_sendpage(conn, &tcp_ctask->sendbuf,

				   &ctask->data_count, &tcp_ctask->sent)) {

		rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf,

				   &ctask->data_count, &tcp_ctask->sent);

		if (rc) {

			ctask->unsol_count -= tcp_ctask->sent - start;

			tcp_ctask->xmstate |= XMSTATE_UNS_DATA;

			/* will continue with this ctask later.. */
@@ -1547,7 +1560,7 @@ handle_xmstate_uns_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
				debug_tcp("tx uns data fail 0x%x\n",

					  dtask->digest);

			}

			return -EAGAIN;

			return rc;

		}



		BUG_ON(tcp_ctask->sent > ctask->total_length);
@@ -1574,12 +1587,13 @@ handle_xmstate_uns_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
	 */

	if (ctask->unsol_count) {

		if (conn->datadgst_en) {

			if (iscsi_digest_final_send(conn, ctask,

			rc = iscsi_digest_final_send(conn, ctask,

						    &dtask->digestbuf,

						    &dtask->digest, 1)) {

						    &dtask->digest, 1);

			if (rc) {

				debug_tcp("send uns digest 0x%x fail\n",

					  dtask->digest);

				return -EAGAIN;

				return rc;

			}

			debug_tcp("sending uns digest 0x%x, more uns\n",

				  dtask->digest);
@@ -1589,12 +1603,13 @@ handle_xmstate_uns_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
	}



	if (conn->datadgst_en && !(tcp_ctask->xmstate & XMSTATE_W_PAD)) {

		if (iscsi_digest_final_send(conn, ctask,

		rc = iscsi_digest_final_send(conn, ctask,

					    &dtask->digestbuf,

					    &dtask->digest, 1)) {

					    &dtask->digest, 1);

		if (rc) {

			debug_tcp("send last uns digest 0x%x fail\n",

				   dtask->digest);

			return -EAGAIN;

			return rc;

		}

		debug_tcp("sending uns digest 0x%x\n",dtask->digest);

	}
@@ -1610,7 +1625,7 @@ handle_xmstate_sol_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;

	struct iscsi_r2t_info *r2t = tcp_ctask->r2t;

	struct iscsi_data_task *dtask = &r2t->dtask;

	int left;

	int left, rc;



	tcp_ctask->xmstate &= ~XMSTATE_SOL_DATA;

	tcp_ctask->dtask = dtask;
@@ -1626,7 +1641,8 @@ solicit_again: 
	if (!r2t->data_count)

		goto data_out_done;



	if (iscsi_sendpage(conn, &r2t->sendbuf, &r2t->data_count, &r2t->sent)) {

	rc = iscsi_sendpage(conn, &r2t->sendbuf, &r2t->data_count, &r2t->sent);

	if (rc) {

		tcp_ctask->xmstate |= XMSTATE_SOL_DATA;

		/* will continue with this ctask later.. */

		if (conn->datadgst_en) {
@@ -1634,7 +1650,7 @@ solicit_again: 
					  (u8 *)&dtask->digest);

			debug_tcp("r2t data send fail 0x%x\n", dtask->digest);

		}

		return -EAGAIN;

		return rc;

	}



	BUG_ON(r2t->data_count < 0);
@@ -1661,12 +1677,13 @@ data_out_done: 
	left = r2t->data_length - r2t->sent;

	if (left) {

		if (conn->datadgst_en) {

			if (iscsi_digest_final_send(conn, ctask,

			rc = iscsi_digest_final_send(conn, ctask,

						    &dtask->digestbuf,

						    &dtask->digest, 1)) {

						    &dtask->digest, 1);

			if (rc) {

				debug_tcp("send r2t data digest 0x%x"

					  "fail\n", dtask->digest);

				return -EAGAIN;

				return rc;

			}

			debug_tcp("r2t data send digest 0x%x\n",

				  dtask->digest);
@@ -1683,11 +1700,12 @@ data_out_done: 
	 */

	BUG_ON(tcp_ctask->r2t_data_count - r2t->data_length < 0);

	if (conn->datadgst_en) {

		if (iscsi_digest_final_send(conn, ctask, &dtask->digestbuf,

					    &dtask->digest, 1)) {

		rc = iscsi_digest_final_send(conn, ctask, &dtask->digestbuf,

					    &dtask->digest, 1);

		if (rc) {

			debug_tcp("send last r2t data digest 0x%x"

				  "fail\n", dtask->digest);

			return -EAGAIN;

			return rc;

		}

		debug_tcp("r2t done dout digest 0x%x\n", dtask->digest);

	}
@@ -1713,15 +1731,16 @@ handle_xmstate_w_pad(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
	struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;

	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;

	struct iscsi_data_task *dtask = tcp_ctask->dtask;

	int sent;

	int sent, rc;



	tcp_ctask->xmstate &= ~XMSTATE_W_PAD;

	iscsi_buf_init_iov(&tcp_ctask->sendbuf, (char*)&tcp_ctask->pad,

			    tcp_ctask->pad_count);

	if (iscsi_sendpage(conn, &tcp_ctask->sendbuf, &tcp_ctask->pad_count,

			   &sent)) {

	rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf, &tcp_ctask->pad_count,

			   &sent);

	if (rc) {

		tcp_ctask->xmstate |= XMSTATE_W_PAD;

		return -EAGAIN;

		return rc;

	}



	if (conn->datadgst_en) {
@@ -1729,22 +1748,24 @@ handle_xmstate_w_pad(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
				     &tcp_ctask->sendbuf.sg, 1);

		/* imm data? */

		if (!dtask) {

			if (iscsi_digest_final_send(conn, ctask,

			rc = iscsi_digest_final_send(conn, ctask,

						    &tcp_ctask->immbuf,

						    &tcp_ctask->immdigest, 1)) {

						    &tcp_ctask->immdigest, 1);

			if (rc) {

				debug_tcp("send padding digest 0x%x"

					  "fail!\n", tcp_ctask->immdigest);

				return -EAGAIN;

				return rc;

			}

			debug_tcp("done with padding, digest 0x%x\n",

				  tcp_ctask->datadigest);

		} else {

			if (iscsi_digest_final_send(conn, ctask,

			rc = iscsi_digest_final_send(conn, ctask,

						    &dtask->digestbuf,

						    &dtask->digest, 1)) {

						    &dtask->digest, 1);

			if (rc) {

				debug_tcp("send padding digest 0x%x"

				          "fail\n", dtask->digest);

				return -EAGAIN;

				return rc;

			}

			debug_tcp("done with padding, digest 0x%x\n",

				  dtask->digest);
@@ -1769,10 +1790,8 @@ iscsi_tcp_ctask_xmit(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask) 
	if (ctask->mtask)

		return rc;



	if (tcp_ctask->xmstate & XMSTATE_R_HDR) {

		rc = handle_xmstate_r_hdr(conn, tcp_ctask);

		return rc;

	}

	if (tcp_ctask->xmstate & XMSTATE_R_HDR)

		return handle_xmstate_r_hdr(conn, tcp_ctask);



	if (tcp_ctask->xmstate & XMSTATE_W_HDR) {

		rc = handle_xmstate_w_hdr(conn, ctask);
@@ -1824,10 +1843,11 @@ solicit_head_again: 
		if (conn->hdrdgst_en)

			iscsi_hdr_digest(conn, &r2t->headbuf,

					(u8*)r2t->dtask.hdrext);

		if (iscsi_sendhdr(conn, &r2t->headbuf, r2t->data_count)) {

		rc = iscsi_sendhdr(conn, &r2t->headbuf, r2t->data_count);

		if (rc) {

			tcp_ctask->xmstate &= ~XMSTATE_SOL_DATA;

			tcp_ctask->xmstate |= XMSTATE_SOL_HDR;

			return -EAGAIN;

			return rc;

		}



		debug_scsi("sol dout [dsn %d itt 0x%x dlen %d sent %d]\n",

drivers/scsi/libiscsi.c

+19 −12
Original line number Diff line number Diff line
@@ -513,10 +513,11 @@ EXPORT_SYMBOL_GPL(iscsi_conn_failure); 
static int iscsi_data_xmit(struct iscsi_conn *conn)

{

	struct iscsi_transport *tt;

	int rc = 0;



	if (unlikely(conn->suspend_tx)) {

		debug_scsi("conn %d Tx suspended!\n", conn->id);

		return 0;

		return -ENODATA;

	}

	tt = conn->session->tt;
@@ -536,13 +537,15 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 
	BUG_ON(conn->ctask && conn->mtask);



	if (conn->ctask) {

		if (tt->xmit_cmd_task(conn, conn->ctask))

		rc = tt->xmit_cmd_task(conn, conn->ctask);

		if (rc)

			goto again;

		/* done with this in-progress ctask */

		conn->ctask = NULL;

	}

	if (conn->mtask) {

	        if (tt->xmit_mgmt_task(conn, conn->mtask))

		rc = tt->xmit_mgmt_task(conn, conn->mtask);

	        if (rc)

		        goto again;

		/* done with this in-progress mtask */

		conn->mtask = NULL;
@@ -556,7 +559,8 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 
			list_add_tail(&conn->mtask->running,

				      &conn->mgmt_run_list);

			spin_unlock_bh(&conn->session->lock);

		        if (tt->xmit_mgmt_task(conn, conn->mtask))

			rc = tt->xmit_mgmt_task(conn, conn->mtask);

		        if (rc)

			        goto again;

	        }

		/* done with this mtask */
@@ -574,7 +578,8 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 
		if (list_empty(&conn->ctask->running))

			list_add_tail(&conn->ctask->running, &conn->run_list);

		spin_unlock_bh(&conn->session->lock);

		if (tt->xmit_cmd_task(conn, conn->ctask))

		rc = tt->xmit_cmd_task(conn, conn->ctask);

		if (rc)

			goto again;

	}

	/* done with this ctask */
@@ -588,32 +593,34 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) 
			list_add_tail(&conn->mtask->running,

				      &conn->mgmt_run_list);

			spin_unlock_bh(&conn->session->lock);

		        if (tt->xmit_mgmt_task(conn, conn->mtask))

		        rc = tt->xmit_mgmt_task(conn, conn->mtask);

			if (rc)

			        goto again;

	        }

		/* done with this mtask */

		conn->mtask = NULL;

	}



	return 0;

	return -ENODATA;



again:

	if (unlikely(conn->suspend_tx))

		return 0;

		return -ENODATA;



	return -EAGAIN;

	return rc;

}



static void iscsi_xmitworker(void *data)

{

	struct iscsi_conn *conn = data;



	int rc;

	/*

	 * serialize Xmit worker on a per-connection basis.

	 */

	mutex_lock(&conn->xmitmutex);

	if (iscsi_data_xmit(conn))

		scsi_queue_work(conn->session->host, &conn->xmitwork);

	do {

		rc = iscsi_data_xmit(conn);

	} while (rc >= 0 || rc == -EAGAIN);

	mutex_unlock(&conn->xmitmutex);

}

include/scsi/scsi_transport_iscsi.h

+6 −2
Original line number Diff line number Diff line
@@ -57,8 +57,12 @@ struct iscsi_mgmt_task; 
 *			Called from queuecommand with session lock held.

 * @init_mgmt_task:	Initialize a iscsi_mgmt_task and any internal structs.

 *			Called from iscsi_conn_send_generic with xmitmutex.

 * @xmit_cmd_task:	requests LLD to transfer cmd task

 * @xmit_mgmt_task:	requests LLD to transfer mgmt task

 * @xmit_cmd_task:	Requests LLD to transfer cmd task. Returns 0 or the

 *			the number of bytes transferred on success, and -Exyz

 *			value on error.

 * @xmit_mgmt_task:	Requests LLD to transfer mgmt task. Returns 0 or the

 *			the number of bytes transferred on success, and -Exyz

 *			value on error.

 * @cleanup_cmd_task:	requests LLD to fail cmd task. Called with xmitmutex

 *			and session->lock after the connection has been

 *			suspended and terminated during recovery. If called

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