[v3] target: Drop iSCSI use of mutex around max_cmd_sn increment

Message ID	87egjyfsmb.fsf@ponos.purestorage.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-scsi-owner@kernel.org> From: Spencer Baugh <spencer.baugh@purestorage.com> To: "Elliott\, Robert \(Server Storage\)" <Elliott@hp.com>, Spencer Baugh <sbaugh@catern.com>, "Nicholas A. Bellinger" <nab@linux-iscsi.org>, Sagi Grimberg <sagig@mellanox.com>, Christoph Hellwig <hch@lst.de>, Bart Van Assche <bart.vanassche@sandisk.com>, Alexei Potashnik <alexei@purestorage.com>, Andy Grover <agrover@redhat.com>, Christophe Vu-Brugier <cvubrugier@fastmail.fm>, Roland Dreier <roland@purestorage.com>, Joern Engel <joern@logfs.org>, Andy Shevchenko <andriy.shevchenko@linux.intel.com>, James Bottomley <JBottomley@Odin.com>, Evgenii Lepikhin <johnlepikhin@gmail.com>, Hannes Reinecke <hare@suse.de>, Al Viro <viro@zeniv.linux.org.uk>, "open list\:TARGET SUBSYSTEM" <linux-scsi@vger.kernel.org>, "open list\:TARGET SUBSYSTEM" <target-devel@vger.kernel.org>, open list <linux-kernel@vger.kernel.org> Cc: Joern Engel <joern@purestorage.com> Subject: Re: [PATCH v3] target: Drop iSCSI use of mutex around max_cmd_sn increment In-Reply-To: <87r3nyg1km.fsf@ponos.purestorage.com> References: <1437602898-15229-2-git-send-email-sbaugh@catern.com> <94D0CD8314A33A4D9D801C0FE68B40295AA03CD1@G9W0745.americas.hpqcorp.net> <87r3nyg1km.fsf@ponos.purestorage.com> User-Agent: Notmuch/0.19 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-redhat-linux-gnu) Date: Thu, 23 Jul 2015 14:53:32 -0700 Message-ID: <87egjyfsmb.fsf@ponos.purestorage.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index ebb1ece..f615d75 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -2555,7 +2555,7 @@ static int iscsit_send_conn_drop_async_message( cmd->stat_sn = conn->stat_sn++; hdr->statsn = cpu_to_be32(cmd->stat_sn); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); hdr->async_event = ISCSI_ASYNC_MSG_DROPPING_CONNECTION; hdr->param1 = cpu_to_be16(cmd->logout_cid); hdr->param2 = cpu_to_be16(conn->sess->sess_ops->DefaultTime2Wait); @@ -2627,7 +2627,7 @@ iscsit_build_datain_pdu(struct iscsi_cmd *cmd, struct iscsi_conn *conn, hdr->statsn = cpu_to_be32(0xFFFFFFFF); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); hdr->datasn = cpu_to_be32(datain->data_sn); hdr->offset = cpu_to_be32(datain->offset); @@ -2838,7 +2838,7 @@ iscsit_build_logout_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built Logout Response ITT: 0x%08x StatSN:" " 0x%08x Response: 0x%02x CID: %hu on CID: %hu\n", @@ -2901,7 +2901,7 @@ iscsit_build_nopin_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built NOPIN %s Response ITT: 0x%08x, TTT: 0x%08x," " StatSN: 0x%08x, Length %u\n", (nopout_response) ? @@ -3048,7 +3048,7 @@ static int iscsit_send_r2t( hdr->ttt = cpu_to_be32(r2t->targ_xfer_tag); hdr->statsn = cpu_to_be32(conn->stat_sn); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); hdr->r2tsn = cpu_to_be32(r2t->r2t_sn); hdr->data_offset = cpu_to_be32(r2t->offset); hdr->data_length = cpu_to_be32(r2t->xfer_len); @@ -3201,7 +3201,7 @@ void iscsit_build_rsp_pdu(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built SCSI Response, ITT: 0x%08x, StatSN: 0x%08x," " Response: 0x%02x, SAM Status: 0x%02x, CID: %hu\n", @@ -3320,7 +3320,7 @@ iscsit_build_task_mgt_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built Task Management Response ITT: 0x%08x," " StatSN: 0x%08x, Response: 0x%02x, CID: %hu\n", @@ -3575,7 +3575,7 @@ iscsit_build_text_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, */ cmd->maxcmdsn_inc = 0; hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built Text Response: ITT: 0x%08x, TTT: 0x%08x, StatSN: 0x%08x," " Length: %u, CID: %hu F: %d C: %d\n", cmd->init_task_tag, @@ -3653,7 +3653,7 @@ iscsit_build_reject(struct iscsi_cmd *cmd, struct iscsi_conn *conn, cmd->stat_sn = conn->stat_sn++; hdr->statsn = cpu_to_be32(cmd->stat_sn); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); } EXPORT_SYMBOL(iscsit_build_reject); diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c index c1898c8..cd2e073 100644 --- a/drivers/target/iscsi/iscsi_target_configfs.c +++ b/drivers/target/iscsi/iscsi_target_configfs.c @@ -656,6 +656,7 @@ static ssize_t lio_target_nacl_show_info( struct iscsi_conn *conn; struct se_session *se_sess; ssize_t rb = 0; + u32 max_cmd_sn; spin_lock_bh(&se_nacl->nacl_sess_lock); se_sess = se_nacl->nacl_sess; @@ -703,11 +704,12 @@ static ssize_t lio_target_nacl_show_info( " Values]-----------------------\n"); rb += sprintf(page+rb, " CmdSN/WR : CmdSN/WC : ExpCmdSN" " : MaxCmdSN : ITT : TTT\n"); + max_cmd_sn = (u32) atomic_read(&sess->max_cmd_sn); rb += sprintf(page+rb, " 0x%08x 0x%08x 0x%08x 0x%08x" " 0x%08x 0x%08x\n", sess->cmdsn_window, - (sess->max_cmd_sn - sess->exp_cmd_sn) + 1, - sess->exp_cmd_sn, sess->max_cmd_sn, + (max_cmd_sn - sess->exp_cmd_sn) + 1, + sess->exp_cmd_sn, max_cmd_sn, sess->init_task_tag, sess->targ_xfer_tag); rb += sprintf(page+rb, "----------------------[iSCSI" " Connections]-------------------------\n"); diff --git a/drivers/target/iscsi/iscsi_target_device.c b/drivers/target/iscsi/iscsi_target_device.c index 5fabcd3..07d2ef6 100644 --- a/drivers/target/iscsi/iscsi_target_device.c +++ b/drivers/target/iscsi/iscsi_target_device.c @@ -47,7 +47,7 @@ void iscsit_determine_maxcmdsn(struct iscsi_session *sess) * core_set_queue_depth_for_node(). */ sess->cmdsn_window = se_nacl->queue_depth; - sess->max_cmd_sn = (sess->max_cmd_sn + se_nacl->queue_depth) - 1; + atomic_set(&sess->max_cmd_sn, (u32) atomic_read(&sess->max_cmd_sn) + se_nacl->queue_depth - 1); } void iscsit_increment_maxcmdsn(struct iscsi_cmd *cmd, struct iscsi_session *sess) @@ -57,9 +57,6 @@ void iscsit_increment_maxcmdsn(struct iscsi_cmd *cmd, struct iscsi_session *sess cmd->maxcmdsn_inc = 1; - mutex_lock(&sess->cmdsn_mutex); - sess->max_cmd_sn += 1; - pr_debug("Updated MaxCmdSN to 0x%08x\n", sess->max_cmd_sn); - mutex_unlock(&sess->cmdsn_mutex); + pr_debug("Updated MaxCmdSN to 0x%08x\n", atomic_inc_return(&sess->max_cmd_sn)); } EXPORT_SYMBOL(iscsit_increment_maxcmdsn); diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c index 3d0fe4f..bd192f8 100644 --- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -330,7 +330,7 @@ static int iscsi_login_zero_tsih_s1( * The FFP CmdSN window values will be allocated from the TPG's * Initiator Node's ACL once the login has been successfully completed. */ - sess->max_cmd_sn = be32_to_cpu(pdu->cmdsn); + atomic_set(&sess->max_cmd_sn, be32_to_cpu(pdu->cmdsn)); sess->sess_ops = kzalloc(sizeof(struct iscsi_sess_ops), GFP_KERNEL); if (!sess->sess_ops) { diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c index 8c02fa3..74d041e 100644 --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -340,7 +340,6 @@ static int iscsi_target_check_first_request( static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_login *login) { u32 padding = 0; - struct iscsi_session *sess = conn->sess; struct iscsi_login_rsp *login_rsp; login_rsp = (struct iscsi_login_rsp *) login->rsp; @@ -352,7 +351,7 @@ static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_log login_rsp->itt = login->init_task_tag; login_rsp->statsn = cpu_to_be32(conn->stat_sn++); login_rsp->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - login_rsp->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + login_rsp->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Sending Login Response, Flags: 0x%02x, ITT: 0x%08x," " ExpCmdSN; 0x%08x, MaxCmdSN: 0x%08x, StatSN: 0x%08x, Length:" @@ -367,10 +366,8 @@ static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_log return -1; login->rsp_length = 0; - mutex_lock(&sess->cmdsn_mutex); - login_rsp->exp_cmdsn = cpu_to_be32(sess->exp_cmd_sn); - login_rsp->max_cmdsn = cpu_to_be32(sess->max_cmd_sn); - mutex_unlock(&sess->cmdsn_mutex); + login_rsp->exp_cmdsn = cpu_to_be32(login_rsp->exp_cmdsn); + login_rsp->max_cmdsn = cpu_to_be32(login_rsp->max_cmdsn); return 0; } diff --git a/drivers/target/iscsi/iscsi_target_tmr.c b/drivers/target/iscsi/iscsi_target_tmr.c index cf59c39..11320df 100644 --- a/drivers/target/iscsi/iscsi_target_tmr.c +++ b/drivers/target/iscsi/iscsi_target_tmr.c @@ -50,7 +50,7 @@ u8 iscsit_tmr_abort_task( pr_err("Unable to locate RefTaskTag: 0x%08x on CID:" " %hu.\n", hdr->rtt, conn->cid); return (iscsi_sna_gte(be32_to_cpu(hdr->refcmdsn), conn->sess->exp_cmd_sn) && - iscsi_sna_lte(be32_to_cpu(hdr->refcmdsn), conn->sess->max_cmd_sn)) ? + iscsi_sna_lte(be32_to_cpu(hdr->refcmdsn), (u32) atomic_read(&conn->sess->max_cmd_sn))) ? ISCSI_TMF_RSP_COMPLETE : ISCSI_TMF_RSP_NO_TASK; } if (ref_cmd->cmd_sn != be32_to_cpu(hdr->refcmdsn)) { diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c index a2bff07..7df4fac 100644 --- a/drivers/target/iscsi/iscsi_target_util.c +++ b/drivers/target/iscsi/iscsi_target_util.c @@ -233,6 +233,7 @@ struct iscsi_r2t *iscsit_get_holder_for_r2tsn( static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cmdsn) { + u32 max_cmdsn; int ret; /* @@ -241,10 +242,10 @@ static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cm * or order CmdSNs due to multiple connection sessions and/or * CRC failures. */ - if (iscsi_sna_gt(cmdsn, sess->max_cmd_sn)) { + max_cmdsn = atomic_read(&sess->max_cmd_sn); + if (iscsi_sna_gt(cmdsn, max_cmdsn)) { pr_err("Received CmdSN: 0x%08x is greater than" - " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn, - sess->max_cmd_sn); + " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn, max_cmdsn); ret = CMDSN_MAXCMDSN_OVERRUN; } else if (cmdsn == sess->exp_cmd_sn) { diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h index 34117b8..11abe3a 100644 --- a/include/target/iscsi/iscsi_target_core.h +++ b/include/target/iscsi/iscsi_target_core.h @@ -635,7 +635,7 @@ struct iscsi_session { /* session wide counter: expected command sequence number */ u32 exp_cmd_sn; /* session wide counter: maximum allowed command sequence number */ - u32 max_cmd_sn; + atomic_t max_cmd_sn; struct list_head sess_ooo_cmdsn_list; /* LIO specific session ID */ -- 2.5.0.rc3 From f5f358beac34f65888031569a03c0d889f5c0ae3 Mon Sep 17 00:00:00 2001 From: Roland Dreier <roland@purestorage.com> Date: Tue, 25 Sep 2012 17:57:38 +0000 Subject: [PATCH] target: Drop iSCSI use of mutex around max_cmd_sn increment In a performance profile, taking a mutex in iscsit_increment_maxcmdsn() shows up very high. However taking a mutex around "sess->max_cmd_sn += 1" seems pretty silly: we're not serializing against other contexts in any useful way. I did a quick audit and there don't appear to be any other places that use max_cmd_sn within the mutex more than once, so this lock can't be providing any useful serialization. Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Spencer Baugh <sbaugh@catern.com> --- drivers/target/iscsi/iscsi_target.c | 18 +++++++++--------- drivers/target/iscsi/iscsi_target_configfs.c | 6 ++++-- drivers/target/iscsi/iscsi_target_device.c | 7 ++----- drivers/target/iscsi/iscsi_target_login.c | 2 +- drivers/target/iscsi/iscsi_target_nego.c | 9 +++------ drivers/target/iscsi/iscsi_target_tmr.c | 2 +- drivers/target/iscsi/iscsi_target_util.c | 7 ++++--- include/target/iscsi/iscsi_target_core.h | 2 +- 8 files changed, 25 insertions(+), 28 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index ebb1ece..f615d75 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -2555,7 +2555,7 @@ static int iscsit_send_conn_drop_async_message( cmd->stat_sn = conn->stat_sn++; hdr->statsn = cpu_to_be32(cmd->stat_sn); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); hdr->async_event = ISCSI_ASYNC_MSG_DROPPING_CONNECTION; hdr->param1 = cpu_to_be16(cmd->logout_cid); hdr->param2 = cpu_to_be16(conn->sess->sess_ops->DefaultTime2Wait); @@ -2627,7 +2627,7 @@ iscsit_build_datain_pdu(struct iscsi_cmd *cmd, struct iscsi_conn *conn, hdr->statsn = cpu_to_be32(0xFFFFFFFF); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); hdr->datasn = cpu_to_be32(datain->data_sn); hdr->offset = cpu_to_be32(datain->offset); @@ -2838,7 +2838,7 @@ iscsit_build_logout_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built Logout Response ITT: 0x%08x StatSN:" " 0x%08x Response: 0x%02x CID: %hu on CID: %hu\n", @@ -2901,7 +2901,7 @@ iscsit_build_nopin_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built NOPIN %s Response ITT: 0x%08x, TTT: 0x%08x," " StatSN: 0x%08x, Length %u\n", (nopout_response) ? @@ -3048,7 +3048,7 @@ static int iscsit_send_r2t( hdr->ttt = cpu_to_be32(r2t->targ_xfer_tag); hdr->statsn = cpu_to_be32(conn->stat_sn); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); hdr->r2tsn = cpu_to_be32(r2t->r2t_sn); hdr->data_offset = cpu_to_be32(r2t->offset); hdr->data_length = cpu_to_be32(r2t->xfer_len); @@ -3201,7 +3201,7 @@ void iscsit_build_rsp_pdu(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built SCSI Response, ITT: 0x%08x, StatSN: 0x%08x," " Response: 0x%02x, SAM Status: 0x%02x, CID: %hu\n", @@ -3320,7 +3320,7 @@ iscsit_build_task_mgt_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built Task Management Response ITT: 0x%08x," " StatSN: 0x%08x, Response: 0x%02x, CID: %hu\n", @@ -3575,7 +3575,7 @@ iscsit_build_text_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, */ cmd->maxcmdsn_inc = 0; hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built Text Response: ITT: 0x%08x, TTT: 0x%08x, StatSN: 0x%08x," " Length: %u, CID: %hu F: %d C: %d\n", cmd->init_task_tag, @@ -3653,7 +3653,7 @@ iscsit_build_reject(struct iscsi_cmd *cmd, struct iscsi_conn *conn, cmd->stat_sn = conn->stat_sn++; hdr->statsn = cpu_to_be32(cmd->stat_sn); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); } EXPORT_SYMBOL(iscsit_build_reject); diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c index c1898c8..cd2e073 100644 --- a/drivers/target/iscsi/iscsi_target_configfs.c +++ b/drivers/target/iscsi/iscsi_target_configfs.c @@ -656,6 +656,7 @@ static ssize_t lio_target_nacl_show_info( struct iscsi_conn *conn; struct se_session *se_sess; ssize_t rb = 0; + u32 max_cmd_sn; spin_lock_bh(&se_nacl->nacl_sess_lock); se_sess = se_nacl->nacl_sess; @@ -703,11 +704,12 @@ static ssize_t lio_target_nacl_show_info( " Values]-----------------------\n"); rb += sprintf(page+rb, " CmdSN/WR : CmdSN/WC : ExpCmdSN" " : MaxCmdSN : ITT : TTT\n"); + max_cmd_sn = (u32) atomic_read(&sess->max_cmd_sn); rb += sprintf(page+rb, " 0x%08x 0x%08x 0x%08x 0x%08x" " 0x%08x 0x%08x\n", sess->cmdsn_window, - (sess->max_cmd_sn - sess->exp_cmd_sn) + 1, - sess->exp_cmd_sn, sess->max_cmd_sn, + (max_cmd_sn - sess->exp_cmd_sn) + 1, + sess->exp_cmd_sn, max_cmd_sn, sess->init_task_tag, sess->targ_xfer_tag); rb += sprintf(page+rb, "----------------------[iSCSI" " Connections]-------------------------\n"); diff --git a/drivers/target/iscsi/iscsi_target_device.c b/drivers/target/iscsi/iscsi_target_device.c index 5fabcd3..07d2ef6 100644 --- a/drivers/target/iscsi/iscsi_target_device.c +++ b/drivers/target/iscsi/iscsi_target_device.c @@ -47,7 +47,7 @@ void iscsit_determine_maxcmdsn(struct iscsi_session *sess) * core_set_queue_depth_for_node(). */ sess->cmdsn_window = se_nacl->queue_depth; - sess->max_cmd_sn = (sess->max_cmd_sn + se_nacl->queue_depth) - 1; + atomic_set(&sess->max_cmd_sn, (u32) atomic_read(&sess->max_cmd_sn) + se_nacl->queue_depth - 1); } void iscsit_increment_maxcmdsn(struct iscsi_cmd *cmd, struct iscsi_session *sess) @@ -57,9 +57,6 @@ void iscsit_increment_maxcmdsn(struct iscsi_cmd *cmd, struct iscsi_session *sess cmd->maxcmdsn_inc = 1; - mutex_lock(&sess->cmdsn_mutex); - sess->max_cmd_sn += 1; - pr_debug("Updated MaxCmdSN to 0x%08x\n", sess->max_cmd_sn); - mutex_unlock(&sess->cmdsn_mutex); + pr_debug("Updated MaxCmdSN to 0x%08x\n", atomic_inc_return(&sess->max_cmd_sn)); } EXPORT_SYMBOL(iscsit_increment_maxcmdsn); diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c index 3d0fe4f..bd192f8 100644 --- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -330,7 +330,7 @@ static int iscsi_login_zero_tsih_s1( * The FFP CmdSN window values will be allocated from the TPG's * Initiator Node's ACL once the login has been successfully completed. */ - sess->max_cmd_sn = be32_to_cpu(pdu->cmdsn); + atomic_set(&sess->max_cmd_sn, be32_to_cpu(pdu->cmdsn)); sess->sess_ops = kzalloc(sizeof(struct iscsi_sess_ops), GFP_KERNEL); if (!sess->sess_ops) { diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c index 8c02fa3..74d041e 100644 --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -340,7 +340,6 @@ static int iscsi_target_check_first_request( static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_login *login) { u32 padding = 0; - struct iscsi_session *sess = conn->sess; struct iscsi_login_rsp *login_rsp; login_rsp = (struct iscsi_login_rsp *) login->rsp; @@ -352,7 +351,7 @@ static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_log login_rsp->itt = login->init_task_tag; login_rsp->statsn = cpu_to_be32(conn->stat_sn++); login_rsp->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - login_rsp->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + login_rsp->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Sending Login Response, Flags: 0x%02x, ITT: 0x%08x," " ExpCmdSN; 0x%08x, MaxCmdSN: 0x%08x, StatSN: 0x%08x, Length:" @@ -367,10 +366,8 @@ static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_log return -1; login->rsp_length = 0; - mutex_lock(&sess->cmdsn_mutex); - login_rsp->exp_cmdsn = cpu_to_be32(sess->exp_cmd_sn); - login_rsp->max_cmdsn = cpu_to_be32(sess->max_cmd_sn); - mutex_unlock(&sess->cmdsn_mutex); + login_rsp->exp_cmdsn = cpu_to_be32(login_rsp->exp_cmdsn); + login_rsp->max_cmdsn = cpu_to_be32(login_rsp->max_cmdsn); return 0; } diff --git a/drivers/target/iscsi/iscsi_target_tmr.c b/drivers/target/iscsi/iscsi_target_tmr.c index cf59c39..11320df 100644 --- a/drivers/target/iscsi/iscsi_target_tmr.c +++ b/drivers/target/iscsi/iscsi_target_tmr.c @@ -50,7 +50,7 @@ u8 iscsit_tmr_abort_task( pr_err("Unable to locate RefTaskTag: 0x%08x on CID:" " %hu.\n", hdr->rtt, conn->cid); return (iscsi_sna_gte(be32_to_cpu(hdr->refcmdsn), conn->sess->exp_cmd_sn) && - iscsi_sna_lte(be32_to_cpu(hdr->refcmdsn), conn->sess->max_cmd_sn)) ? + iscsi_sna_lte(be32_to_cpu(hdr->refcmdsn), (u32) atomic_read(&conn->sess->max_cmd_sn))) ? ISCSI_TMF_RSP_COMPLETE : ISCSI_TMF_RSP_NO_TASK; } if (ref_cmd->cmd_sn != be32_to_cpu(hdr->refcmdsn)) { diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c index a2bff07..7df4fac 100644 --- a/drivers/target/iscsi/iscsi_target_util.c +++ b/drivers/target/iscsi/iscsi_target_util.c @@ -233,6 +233,7 @@ struct iscsi_r2t *iscsit_get_holder_for_r2tsn( static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cmdsn) { + u32 max_cmdsn; int ret; /* @@ -241,10 +242,10 @@ static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cm * or order CmdSNs due to multiple connection sessions and/or * CRC failures. */ - if (iscsi_sna_gt(cmdsn, sess->max_cmd_sn)) { + max_cmdsn = atomic_read(&sess->max_cmd_sn); + if (iscsi_sna_gt(cmdsn, max_cmdsn)) { pr_err("Received CmdSN: 0x%08x is greater than" - " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn, - sess->max_cmd_sn); + " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn, max_cmdsn); ret = CMDSN_MAXCMDSN_OVERRUN; } else if (cmdsn == sess->exp_cmd_sn) { diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h index 34117b8..11abe3a 100644 --- a/include/target/iscsi/iscsi_target_core.h +++ b/include/target/iscsi/iscsi_target_core.h @@ -635,7 +635,7 @@ struct iscsi_session { /* session wide counter: expected command sequence number */ u32 exp_cmd_sn; /* session wide counter: maximum allowed command sequence number */ - u32 max_cmd_sn; + atomic_t max_cmd_sn; struct list_head sess_ooo_cmdsn_list; /* LIO specific session ID */ -- 2.5.0.rc3 From f5f358beac34f65888031569a03c0d889f5c0ae3 Mon Sep 17 00:00:00 2001 From: Roland Dreier <roland@purestorage.com> Date: Tue, 25 Sep 2012 17:57:38 +0000 Subject: [PATCH] target: Drop iSCSI use of mutex around max_cmd_sn increment In a performance profile, taking a mutex in iscsit_increment_maxcmdsn() shows up very high. However taking a mutex around "sess->max_cmd_sn += 1" seems pretty silly: we're not serializing against other contexts in any useful way. I did a quick audit and there don't appear to be any other places that use max_cmd_sn within the mutex more than once, so this lock can't be providing any useful serialization. Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Spencer Baugh <sbaugh@catern.com> --- drivers/target/iscsi/iscsi_target.c | 18 +++++++++--------- drivers/target/iscsi/iscsi_target_configfs.c | 6 ++++-- drivers/target/iscsi/iscsi_target_device.c | 7 ++----- drivers/target/iscsi/iscsi_target_login.c | 2 +- drivers/target/iscsi/iscsi_target_nego.c | 9 +++------ drivers/target/iscsi/iscsi_target_tmr.c | 2 +- drivers/target/iscsi/iscsi_target_util.c | 7 ++++--- include/target/iscsi/iscsi_target_core.h | 2 +- 8 files changed, 25 insertions(+), 28 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index ebb1ece..f615d75 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -2555,7 +2555,7 @@ static int iscsit_send_conn_drop_async_message( cmd->stat_sn = conn->stat_sn++; hdr->statsn = cpu_to_be32(cmd->stat_sn); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); hdr->async_event = ISCSI_ASYNC_MSG_DROPPING_CONNECTION; hdr->param1 = cpu_to_be16(cmd->logout_cid); hdr->param2 = cpu_to_be16(conn->sess->sess_ops->DefaultTime2Wait); @@ -2627,7 +2627,7 @@ iscsit_build_datain_pdu(struct iscsi_cmd *cmd, struct iscsi_conn *conn, hdr->statsn = cpu_to_be32(0xFFFFFFFF); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); hdr->datasn = cpu_to_be32(datain->data_sn); hdr->offset = cpu_to_be32(datain->offset); @@ -2838,7 +2838,7 @@ iscsit_build_logout_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built Logout Response ITT: 0x%08x StatSN:" " 0x%08x Response: 0x%02x CID: %hu on CID: %hu\n", @@ -2901,7 +2901,7 @@ iscsit_build_nopin_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built NOPIN %s Response ITT: 0x%08x, TTT: 0x%08x," " StatSN: 0x%08x, Length %u\n", (nopout_response) ? @@ -3048,7 +3048,7 @@ static int iscsit_send_r2t( hdr->ttt = cpu_to_be32(r2t->targ_xfer_tag); hdr->statsn = cpu_to_be32(conn->stat_sn); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); hdr->r2tsn = cpu_to_be32(r2t->r2t_sn); hdr->data_offset = cpu_to_be32(r2t->offset); hdr->data_length = cpu_to_be32(r2t->xfer_len); @@ -3201,7 +3201,7 @@ void iscsit_build_rsp_pdu(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built SCSI Response, ITT: 0x%08x, StatSN: 0x%08x," " Response: 0x%02x, SAM Status: 0x%02x, CID: %hu\n", @@ -3320,7 +3320,7 @@ iscsit_build_task_mgt_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, iscsit_increment_maxcmdsn(cmd, conn->sess); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built Task Management Response ITT: 0x%08x," " StatSN: 0x%08x, Response: 0x%02x, CID: %hu\n", @@ -3575,7 +3575,7 @@ iscsit_build_text_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn, */ cmd->maxcmdsn_inc = 0; hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Built Text Response: ITT: 0x%08x, TTT: 0x%08x, StatSN: 0x%08x," " Length: %u, CID: %hu F: %d C: %d\n", cmd->init_task_tag, @@ -3653,7 +3653,7 @@ iscsit_build_reject(struct iscsi_cmd *cmd, struct iscsi_conn *conn, cmd->stat_sn = conn->stat_sn++; hdr->statsn = cpu_to_be32(cmd->stat_sn); hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - hdr->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + hdr->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); } EXPORT_SYMBOL(iscsit_build_reject); diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c index c1898c8..cd2e073 100644 --- a/drivers/target/iscsi/iscsi_target_configfs.c +++ b/drivers/target/iscsi/iscsi_target_configfs.c @@ -656,6 +656,7 @@ static ssize_t lio_target_nacl_show_info( struct iscsi_conn *conn; struct se_session *se_sess; ssize_t rb = 0; + u32 max_cmd_sn; spin_lock_bh(&se_nacl->nacl_sess_lock); se_sess = se_nacl->nacl_sess; @@ -703,11 +704,12 @@ static ssize_t lio_target_nacl_show_info( " Values]-----------------------\n"); rb += sprintf(page+rb, " CmdSN/WR : CmdSN/WC : ExpCmdSN" " : MaxCmdSN : ITT : TTT\n"); + max_cmd_sn = (u32) atomic_read(&sess->max_cmd_sn); rb += sprintf(page+rb, " 0x%08x 0x%08x 0x%08x 0x%08x" " 0x%08x 0x%08x\n", sess->cmdsn_window, - (sess->max_cmd_sn - sess->exp_cmd_sn) + 1, - sess->exp_cmd_sn, sess->max_cmd_sn, + (max_cmd_sn - sess->exp_cmd_sn) + 1, + sess->exp_cmd_sn, max_cmd_sn, sess->init_task_tag, sess->targ_xfer_tag); rb += sprintf(page+rb, "----------------------[iSCSI" " Connections]-------------------------\n"); diff --git a/drivers/target/iscsi/iscsi_target_device.c b/drivers/target/iscsi/iscsi_target_device.c index 5fabcd3..07d2ef6 100644 --- a/drivers/target/iscsi/iscsi_target_device.c +++ b/drivers/target/iscsi/iscsi_target_device.c @@ -47,7 +47,7 @@ void iscsit_determine_maxcmdsn(struct iscsi_session *sess) * core_set_queue_depth_for_node(). */ sess->cmdsn_window = se_nacl->queue_depth; - sess->max_cmd_sn = (sess->max_cmd_sn + se_nacl->queue_depth) - 1; + atomic_set(&sess->max_cmd_sn, (u32) atomic_read(&sess->max_cmd_sn) + se_nacl->queue_depth - 1); } void iscsit_increment_maxcmdsn(struct iscsi_cmd *cmd, struct iscsi_session *sess) @@ -57,9 +57,6 @@ void iscsit_increment_maxcmdsn(struct iscsi_cmd *cmd, struct iscsi_session *sess cmd->maxcmdsn_inc = 1; - mutex_lock(&sess->cmdsn_mutex); - sess->max_cmd_sn += 1; - pr_debug("Updated MaxCmdSN to 0x%08x\n", sess->max_cmd_sn); - mutex_unlock(&sess->cmdsn_mutex); + pr_debug("Updated MaxCmdSN to 0x%08x\n", atomic_inc_return(&sess->max_cmd_sn)); } EXPORT_SYMBOL(iscsit_increment_maxcmdsn); diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c index 3d0fe4f..bd192f8 100644 --- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -330,7 +330,7 @@ static int iscsi_login_zero_tsih_s1( * The FFP CmdSN window values will be allocated from the TPG's * Initiator Node's ACL once the login has been successfully completed. */ - sess->max_cmd_sn = be32_to_cpu(pdu->cmdsn); + atomic_set(&sess->max_cmd_sn, be32_to_cpu(pdu->cmdsn)); sess->sess_ops = kzalloc(sizeof(struct iscsi_sess_ops), GFP_KERNEL); if (!sess->sess_ops) { diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c index 8c02fa3..74d041e 100644 --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -340,7 +340,6 @@ static int iscsi_target_check_first_request( static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_login *login) { u32 padding = 0; - struct iscsi_session *sess = conn->sess; struct iscsi_login_rsp *login_rsp; login_rsp = (struct iscsi_login_rsp *) login->rsp; @@ -352,7 +351,7 @@ static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_log login_rsp->itt = login->init_task_tag; login_rsp->statsn = cpu_to_be32(conn->stat_sn++); login_rsp->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_sn); - login_rsp->max_cmdsn = cpu_to_be32(conn->sess->max_cmd_sn); + login_rsp->max_cmdsn = cpu_to_be32((u32) atomic_read(&conn->sess->max_cmd_sn)); pr_debug("Sending Login Response, Flags: 0x%02x, ITT: 0x%08x," " ExpCmdSN; 0x%08x, MaxCmdSN: 0x%08x, StatSN: 0x%08x, Length:" @@ -367,10 +366,8 @@ static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_log return -1; login->rsp_length = 0; - mutex_lock(&sess->cmdsn_mutex); - login_rsp->exp_cmdsn = cpu_to_be32(sess->exp_cmd_sn); - login_rsp->max_cmdsn = cpu_to_be32(sess->max_cmd_sn); - mutex_unlock(&sess->cmdsn_mutex); + login_rsp->exp_cmdsn = cpu_to_be32(login_rsp->exp_cmdsn); + login_rsp->max_cmdsn = cpu_to_be32(login_rsp->max_cmdsn); return 0; } diff --git a/drivers/target/iscsi/iscsi_target_tmr.c b/drivers/target/iscsi/iscsi_target_tmr.c index cf59c39..11320df 100644 --- a/drivers/target/iscsi/iscsi_target_tmr.c +++ b/drivers/target/iscsi/iscsi_target_tmr.c @@ -50,7 +50,7 @@ u8 iscsit_tmr_abort_task( pr_err("Unable to locate RefTaskTag: 0x%08x on CID:" " %hu.\n", hdr->rtt, conn->cid); return (iscsi_sna_gte(be32_to_cpu(hdr->refcmdsn), conn->sess->exp_cmd_sn) && - iscsi_sna_lte(be32_to_cpu(hdr->refcmdsn), conn->sess->max_cmd_sn)) ? + iscsi_sna_lte(be32_to_cpu(hdr->refcmdsn), (u32) atomic_read(&conn->sess->max_cmd_sn))) ? ISCSI_TMF_RSP_COMPLETE : ISCSI_TMF_RSP_NO_TASK; } if (ref_cmd->cmd_sn != be32_to_cpu(hdr->refcmdsn)) { diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c index a2bff07..7df4fac 100644 --- a/drivers/target/iscsi/iscsi_target_util.c +++ b/drivers/target/iscsi/iscsi_target_util.c @@ -233,6 +233,7 @@ struct iscsi_r2t *iscsit_get_holder_for_r2tsn( static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cmdsn) { + u32 max_cmdsn; int ret; /* @@ -241,10 +242,10 @@ static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cm * or order CmdSNs due to multiple connection sessions and/or * CRC failures. */ - if (iscsi_sna_gt(cmdsn, sess->max_cmd_sn)) { + max_cmdsn = atomic_read(&sess->max_cmd_sn); + if (iscsi_sna_gt(cmdsn, max_cmdsn)) { pr_err("Received CmdSN: 0x%08x is greater than" - " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn, - sess->max_cmd_sn); + " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn, max_cmdsn); ret = CMDSN_MAXCMDSN_OVERRUN; } else if (cmdsn == sess->exp_cmd_sn) { diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h index 34117b8..11abe3a 100644 --- a/include/target/iscsi/iscsi_target_core.h +++ b/include/target/iscsi/iscsi_target_core.h @@ -635,7 +635,7 @@ struct iscsi_session { /* session wide counter: expected command sequence number */ u32 exp_cmd_sn; /* session wide counter: maximum allowed command sequence number */ - u32 max_cmd_sn; + atomic_t max_cmd_sn; struct list_head sess_ooo_cmdsn_list; /* LIO specific session ID */

[v3] target: Drop iSCSI use of mutex around max_cmd_sn increment

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