evie/android_kernel_oneplus_msm8998
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target: Drop iSCSI use of mutex around max_cmd_sn increment

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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.

(Get correct values for logging - fix whitespace damage)

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Spencer Baugh <sbaugh@catern.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Roland Dreier 2015-07-23 14:53:32 -07:00 • committed by Nicholas Bellinger
parent 24c7d6c731
commit 109e238174
8 changed files with 25 additions and 28 deletions
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18
drivers/target/iscsi/iscsi_target.c
View file

@ -2555,7 +2555,7 @@ static int iscsit_send_conn_drop_async_message(
cmd->stat_sn = conn->stat_sn++; cmd->stat_sn = conn->stat_sn++;
hdr->statsn = cpu_to_be32(cmd->stat_sn); hdr->statsn = cpu_to_be32(cmd->stat_sn);
hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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->async_event = ISCSI_ASYNC_MSG_DROPPING_CONNECTION;
hdr->param1 = cpu_to_be16(cmd->logout_cid); hdr->param1 = cpu_to_be16(cmd->logout_cid);
hdr->param2 = cpu_to_be16(conn->sess->sess_ops->DefaultTime2Wait); 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->statsn = cpu_to_be32(0xFFFFFFFF);
hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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->datasn = cpu_to_be32(datain->data_sn); hdr->datasn = cpu_to_be32(datain->data_sn);
hdr->offset = cpu_to_be32(datain->offset); 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); iscsit_increment_maxcmdsn(cmd, conn->sess);
hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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));
pr_debug("Built Logout Response ITT: 0x%08x StatSN:" pr_debug("Built Logout Response ITT: 0x%08x StatSN:"
" 0x%08x Response: 0x%02x CID: %hu on CID: %hu\n", " 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); iscsit_increment_maxcmdsn(cmd, conn->sess);
hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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));
pr_debug("Built NOPIN %s Response ITT: 0x%08x, TTT: 0x%08x," pr_debug("Built NOPIN %s Response ITT: 0x%08x, TTT: 0x%08x,"
" StatSN: 0x%08x, Length %u\n", (nopout_response) ? " 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->ttt = cpu_to_be32(r2t->targ_xfer_tag);
hdr->statsn = cpu_to_be32(conn->stat_sn); hdr->statsn = cpu_to_be32(conn->stat_sn);
hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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->r2tsn = cpu_to_be32(r2t->r2t_sn);
hdr->data_offset = cpu_to_be32(r2t->offset); hdr->data_offset = cpu_to_be32(r2t->offset);
hdr->data_length = cpu_to_be32(r2t->xfer_len); 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); iscsit_increment_maxcmdsn(cmd, conn->sess);
hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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));
pr_debug("Built SCSI Response, ITT: 0x%08x, StatSN: 0x%08x," pr_debug("Built SCSI Response, ITT: 0x%08x, StatSN: 0x%08x,"
" Response: 0x%02x, SAM Status: 0x%02x, CID: %hu\n", " 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); iscsit_increment_maxcmdsn(cmd, conn->sess);
hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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));
pr_debug("Built Task Management Response ITT: 0x%08x," pr_debug("Built Task Management Response ITT: 0x%08x,"
" StatSN: 0x%08x, Response: 0x%02x, CID: %hu\n", " 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; cmd->maxcmdsn_inc = 0;
hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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));
pr_debug("Built Text Response: ITT: 0x%08x, TTT: 0x%08x, StatSN: 0x%08x," 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, " 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++; cmd->stat_sn = conn->stat_sn++;
hdr->statsn = cpu_to_be32(cmd->stat_sn); hdr->statsn = cpu_to_be32(cmd->stat_sn);
hdr->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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); EXPORT_SYMBOL(iscsit_build_reject);

6
drivers/target/iscsi/iscsi_target_configfs.c
View file

@ -656,6 +656,7 @@ static ssize_t lio_target_nacl_show_info(
struct iscsi_conn *conn; struct iscsi_conn *conn;
struct se_session *se_sess; struct se_session *se_sess;
ssize_t rb = 0; ssize_t rb = 0;
u32 max_cmd_sn;
spin_lock_bh(&se_nacl->nacl_sess_lock); spin_lock_bh(&se_nacl->nacl_sess_lock);
se_sess = se_nacl->nacl_sess; se_sess = se_nacl->nacl_sess;
@ -703,11 +704,12 @@ static ssize_t lio_target_nacl_show_info(
" Values]-----------------------\n"); " Values]-----------------------\n");
rb += sprintf(page+rb, " CmdSN/WR : CmdSN/WC : ExpCmdSN" rb += sprintf(page+rb, " CmdSN/WR : CmdSN/WC : ExpCmdSN"
" : MaxCmdSN : ITT : TTT\n"); " : 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" rb += sprintf(page+rb, " 0x%08x 0x%08x 0x%08x 0x%08x"
" 0x%08x 0x%08x\n", " 0x%08x 0x%08x\n",
sess->cmdsn_window, sess->cmdsn_window,
(sess->max_cmd_sn - sess->exp_cmd_sn) + 1, (max_cmd_sn - sess->exp_cmd_sn) + 1,
sess->exp_cmd_sn, sess->max_cmd_sn, sess->exp_cmd_sn, max_cmd_sn,
sess->init_task_tag, sess->targ_xfer_tag); sess->init_task_tag, sess->targ_xfer_tag);
rb += sprintf(page+rb, "----------------------[iSCSI" rb += sprintf(page+rb, "----------------------[iSCSI"
" Connections]-------------------------\n"); " Connections]-------------------------\n");

7
drivers/target/iscsi/iscsi_target_device.c
View file

@ -47,7 +47,7 @@ void iscsit_determine_maxcmdsn(struct iscsi_session *sess)
* core_set_queue_depth_for_node(). * core_set_queue_depth_for_node().
*/ */
sess->cmdsn_window = se_nacl->queue_depth; 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) 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; cmd->maxcmdsn_inc = 1;
mutex_lock(&sess->cmdsn_mutex); pr_debug("Updated MaxCmdSN to 0x%08x\n", atomic_inc_return(&sess->max_cmd_sn));
sess->max_cmd_sn += 1;
pr_debug("Updated MaxCmdSN to 0x%08x\n", sess->max_cmd_sn);
mutex_unlock(&sess->cmdsn_mutex);
} }
EXPORT_SYMBOL(iscsit_increment_maxcmdsn); EXPORT_SYMBOL(iscsit_increment_maxcmdsn);

2
drivers/target/iscsi/iscsi_target_login.c
View file

@ -330,7 +330,7 @@ static int iscsi_login_zero_tsih_s1(
* The FFP CmdSN window values will be allocated from the TPG's * The FFP CmdSN window values will be allocated from the TPG's
* Initiator Node's ACL once the login has been successfully completed. * 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); sess->sess_ops = kzalloc(sizeof(struct iscsi_sess_ops), GFP_KERNEL);
if (!sess->sess_ops) { if (!sess->sess_ops) {

9
drivers/target/iscsi/iscsi_target_nego.c
View file

@ -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) static int iscsi_target_do_tx_login_io(struct iscsi_conn *conn, struct iscsi_login *login)
{ {
u32 padding = 0; u32 padding = 0;
struct iscsi_session *sess = conn->sess;
struct iscsi_login_rsp *login_rsp; struct iscsi_login_rsp *login_rsp;
login_rsp = (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->itt = login->init_task_tag;
login_rsp->statsn = cpu_to_be32(conn->stat_sn++); login_rsp->statsn = cpu_to_be32(conn->stat_sn++);
login_rsp->exp_cmdsn = cpu_to_be32(conn->sess->exp_cmd_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," pr_debug("Sending Login Response, Flags: 0x%02x, ITT: 0x%08x,"
" ExpCmdSN; 0x%08x, MaxCmdSN: 0x%08x, StatSN: 0x%08x, Length:" " 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; return -1;
login->rsp_length = 0; login->rsp_length = 0;
mutex_lock(&sess->cmdsn_mutex); login_rsp->exp_cmdsn = cpu_to_be32(login_rsp->exp_cmdsn);
login_rsp->exp_cmdsn = cpu_to_be32(sess->exp_cmd_sn); login_rsp->max_cmdsn = cpu_to_be32(login_rsp->max_cmdsn);
login_rsp->max_cmdsn = cpu_to_be32(sess->max_cmd_sn);
mutex_unlock(&sess->cmdsn_mutex);
return 0; return 0;
} }

2
drivers/target/iscsi/iscsi_target_tmr.c
View file

@ -50,7 +50,7 @@ u8 iscsit_tmr_abort_task(
pr_err("Unable to locate RefTaskTag: 0x%08x on CID:" pr_err("Unable to locate RefTaskTag: 0x%08x on CID:"
" %hu.\n", hdr->rtt, conn->cid); " %hu.\n", hdr->rtt, conn->cid);
return (iscsi_sna_gte(be32_to_cpu(hdr->refcmdsn), conn->sess->exp_cmd_sn) && 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; ISCSI_TMF_RSP_COMPLETE : ISCSI_TMF_RSP_NO_TASK;
} }
if (ref_cmd->cmd_sn != be32_to_cpu(hdr->refcmdsn)) { if (ref_cmd->cmd_sn != be32_to_cpu(hdr->refcmdsn)) {

7
drivers/target/iscsi/iscsi_target_util.c
View file

@ -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) static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cmdsn)
{ {
u32 max_cmdsn;
int ret; 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 * or order CmdSNs due to multiple connection sessions and/or
* CRC failures. * 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" pr_err("Received CmdSN: 0x%08x is greater than"
" MaxCmdSN: 0x%08x, ignoring.\n", cmdsn, " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn, max_cmdsn);
sess->max_cmd_sn);
ret = CMDSN_MAXCMDSN_OVERRUN; ret = CMDSN_MAXCMDSN_OVERRUN;
} else if (cmdsn == sess->exp_cmd_sn) { } else if (cmdsn == sess->exp_cmd_sn) {

2
include/target/iscsi/iscsi_target_core.h
View file

@ -637,7 +637,7 @@ struct iscsi_session {
/* session wide counter: expected command sequence number */ /* session wide counter: expected command sequence number */
u32 exp_cmd_sn; u32 exp_cmd_sn;
/* session wide counter: maximum allowed command sequence number */ /* session wide counter: maximum allowed command sequence number */
u32 max_cmd_sn; atomic_t max_cmd_sn;
struct list_head sess_ooo_cmdsn_list; struct list_head sess_ooo_cmdsn_list;
/* LIO specific session ID */ /* LIO specific session ID */