From 3219e5294150aee7d389e19029f49b44fb6b5c9f Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Tue, 30 May 2006 00:37:28 -0500 Subject: [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: Mike Christie Signed-off-by: James Bottomley diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c index 2abda80..7fa8593 100644 --- a/drivers/scsi/iscsi_tcp.c +++ b/drivers/scsi/iscsi_tcp.c @@ -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", diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index 256b87a..2673a11 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -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); } diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h index 92129b9..b684426 100644 --- a/include/scsi/scsi_transport_iscsi.h +++ b/include/scsi/scsi_transport_iscsi.h @@ -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 -- cgit v0.10.2