iscsi-target: Convert iscsi_session statistics to atomic_long_t

This patch converts a handful of iscsi_session statistics to type
atomic_long_t, instead of using iscsi_session->session_stats_lock
when incrementing these values.

More importantly, go ahead and drop the spinlock usage within
iscsit_setup_scsi_cmd(), iscsit_check_dataout_hdr(),
iscsit_send_datain(), and iscsit_build_rsp_pdu() fast-path code.

(Squash in Roland's  target: Remove write-only stats fields and lock
from struct se_node_acl)

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index ba9787d..bf76fc4 100644 (file)
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -800,14 +800,7 @@ int iscsit_setup_scsi_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
        int iscsi_task_attr;
        int sam_task_attr;
 
-       spin_lock_bh(&conn->sess->session_stats_lock);
-       conn->sess->cmd_pdus++;
-       if (conn->sess->se_sess->se_node_acl) {
-               spin_lock(&conn->sess->se_sess->se_node_acl->stats_lock);
-               conn->sess->se_sess->se_node_acl->num_cmds++;
-               spin_unlock(&conn->sess->se_sess->se_node_acl->stats_lock);
-       }
-       spin_unlock_bh(&conn->sess->session_stats_lock);
+       atomic_long_inc(&conn->sess->cmd_pdus);
 
        hdr                     = (struct iscsi_scsi_req *) buf;
        payload_length          = ntoh24(hdr->dlength);
@@ -1254,14 +1247,7 @@ iscsit_check_dataout_hdr(struct iscsi_conn *conn, unsigned char *buf,
        }
 
        /* iSCSI write */
-       spin_lock_bh(&conn->sess->session_stats_lock);
-       conn->sess->rx_data_octets += payload_length;
-       if (conn->sess->se_sess->se_node_acl) {
-               spin_lock(&conn->sess->se_sess->se_node_acl->stats_lock);
-               conn->sess->se_sess->se_node_acl->write_bytes += payload_length;
-               spin_unlock(&conn->sess->se_sess->se_node_acl->stats_lock);
-       }
-       spin_unlock_bh(&conn->sess->session_stats_lock);
+       atomic_long_add(payload_length, &conn->sess->rx_data_octets);
 
        if (payload_length > conn->conn_ops->MaxXmitDataSegmentLength) {
                pr_err("DataSegmentLength: %u is greater than"
@@ -2631,14 +2617,7 @@ static int iscsit_send_datain(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
                return -1;
        }
 
-       spin_lock_bh(&conn->sess->session_stats_lock);
-       conn->sess->tx_data_octets += datain.length;
-       if (conn->sess->se_sess->se_node_acl) {
-               spin_lock(&conn->sess->se_sess->se_node_acl->stats_lock);
-               conn->sess->se_sess->se_node_acl->read_bytes += datain.length;
-               spin_unlock(&conn->sess->se_sess->se_node_acl->stats_lock);
-       }
-       spin_unlock_bh(&conn->sess->session_stats_lock);
+       atomic_long_add(datain.length, &conn->sess->tx_data_octets);
        /*
         * Special case for successfully execution w/ both DATAIN
         * and Sense Data.
@@ -3163,9 +3142,7 @@ void iscsit_build_rsp_pdu(struct iscsi_cmd *cmd, struct iscsi_conn *conn,
        if (inc_stat_sn)
                cmd->stat_sn = conn->stat_sn++;
 
-       spin_lock_bh(&conn->sess->session_stats_lock);
-       conn->sess->rsp_pdus++;
-       spin_unlock_bh(&conn->sess->session_stats_lock);
+       atomic_long_inc(&conn->sess->rsp_pdus);
 
        memset(hdr, 0, ISCSI_HDR_LEN);
        hdr->opcode             = ISCSI_OP_SCSI_CMD_RSP;
@@ -4114,9 +4091,7 @@ restart:
                                 * hit default in the switch below.
                                 */
                                memset(buffer, 0xff, ISCSI_HDR_LEN);
-                               spin_lock_bh(&conn->sess->session_stats_lock);
-                               conn->sess->conn_digest_errors++;
-                               spin_unlock_bh(&conn->sess->session_stats_lock);
+                               atomic_long_inc(&conn->sess->conn_digest_errors);
                        } else {
                                pr_debug("Got HeaderDigest CRC32C"
                                                " 0x%08x\n", checksum);

diff --git a/drivers/target/iscsi/iscsi_target_core.h b/drivers/target/iscsi/iscsi_target_core.h
index b03ee2f..f2094d2 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_core.h
+++ b/drivers/target/iscsi/iscsi_target_core.h
@@ -651,14 +651,13 @@ struct iscsi_session {
        /* Used for session reference counting */
        int                     session_usage_count;
        int                     session_waiting_on_uc;
-       u32                     cmd_pdus;
-       u32                     rsp_pdus;
-       u64                     tx_data_octets;
-       u64                     rx_data_octets;
-       u32                     conn_digest_errors;
-       u32                     conn_timeout_errors;
+       atomic_long_t           cmd_pdus;
+       atomic_long_t           rsp_pdus;
+       atomic_long_t           tx_data_octets;
+       atomic_long_t           rx_data_octets;
+       atomic_long_t           conn_digest_errors;
+       atomic_long_t           conn_timeout_errors;
        u64                     creation_time;
-       spinlock_t              session_stats_lock;
        /* Number of active connections */
        atomic_t                nconn;
        atomic_t                session_continuation;

diff --git a/drivers/target/iscsi/iscsi_target_erl0.c b/drivers/target/iscsi/iscsi_target_erl0.c
index cbea7f1..0d1e6ee 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_erl0.c
+++ b/drivers/target/iscsi/iscsi_target_erl0.c
@@ -785,7 +785,7 @@ static void iscsit_handle_time2retain_timeout(unsigned long data)
                tiqn->sess_err_stats.last_sess_failure_type =
                                ISCSI_SESS_ERR_CXN_TIMEOUT;
                tiqn->sess_err_stats.cxn_timeout_errors++;
-               sess->conn_timeout_errors++;
+               atomic_long_inc(&sess->conn_timeout_errors);
                spin_unlock(&tiqn->sess_err_stats.lock);
        }
        }

diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index 646632a..4eb93b2 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -305,7 +305,6 @@ static int iscsi_login_zero_tsih_s1(
        }
 
        sess->creation_time = get_jiffies_64();
-       spin_lock_init(&sess->session_stats_lock);
        /*
         * The FFP CmdSN window values will be allocated from the TPG's
         * Initiator Node's ACL once the login has been successfully completed.

diff --git a/drivers/target/iscsi/iscsi_target_stat.c b/drivers/target/iscsi/iscsi_target_stat.c
index f788e8b..1033955 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_stat.c
+++ b/drivers/target/iscsi/iscsi_target_stat.c
@@ -792,7 +792,8 @@ static ssize_t iscsi_stat_sess_show_attr_cmd_pdus(
        if (se_sess) {
                sess = se_sess->fabric_sess_ptr;
                if (sess)
-                       ret = snprintf(page, PAGE_SIZE, "%u\n", sess->cmd_pdus);
+                       ret = snprintf(page, PAGE_SIZE, "%lu\n",
+                                      atomic_long_read(&sess->cmd_pdus));
        }
        spin_unlock_bh(&se_nacl->nacl_sess_lock);
 
@@ -815,7 +816,8 @@ static ssize_t iscsi_stat_sess_show_attr_rsp_pdus(
        if (se_sess) {
                sess = se_sess->fabric_sess_ptr;
                if (sess)
-                       ret = snprintf(page, PAGE_SIZE, "%u\n", sess->rsp_pdus);
+                       ret = snprintf(page, PAGE_SIZE, "%lu\n",
+                                      atomic_long_read(&sess->rsp_pdus));
        }
        spin_unlock_bh(&se_nacl->nacl_sess_lock);
 
@@ -838,8 +840,8 @@ static ssize_t iscsi_stat_sess_show_attr_txdata_octs(
        if (se_sess) {
                sess = se_sess->fabric_sess_ptr;
                if (sess)
-                       ret = snprintf(page, PAGE_SIZE, "%llu\n",
-                               (unsigned long long)sess->tx_data_octets);
+                       ret = snprintf(page, PAGE_SIZE, "%lu\n",
+                                      atomic_long_read(&sess->tx_data_octets));
        }
        spin_unlock_bh(&se_nacl->nacl_sess_lock);
 
@@ -862,8 +864,8 @@ static ssize_t iscsi_stat_sess_show_attr_rxdata_octs(
        if (se_sess) {
                sess = se_sess->fabric_sess_ptr;
                if (sess)
-                       ret = snprintf(page, PAGE_SIZE, "%llu\n",
-                               (unsigned long long)sess->rx_data_octets);
+                       ret = snprintf(page, PAGE_SIZE, "%lu\n",
+                                      atomic_long_read(&sess->rx_data_octets));
        }
        spin_unlock_bh(&se_nacl->nacl_sess_lock);
 
@@ -886,8 +888,8 @@ static ssize_t iscsi_stat_sess_show_attr_conn_digest_errors(
        if (se_sess) {
                sess = se_sess->fabric_sess_ptr;
                if (sess)
-                       ret = snprintf(page, PAGE_SIZE, "%u\n",
-                                       sess->conn_digest_errors);
+                       ret = snprintf(page, PAGE_SIZE, "%lu\n",
+                                      atomic_long_read(&sess->conn_digest_errors));
        }
        spin_unlock_bh(&se_nacl->nacl_sess_lock);
 
@@ -910,8 +912,8 @@ static ssize_t iscsi_stat_sess_show_attr_conn_timeout_errors(
        if (se_sess) {
                sess = se_sess->fabric_sess_ptr;
                if (sess)
-                       ret = snprintf(page, PAGE_SIZE, "%u\n",
-                                       sess->conn_timeout_errors);
+                       ret = snprintf(page, PAGE_SIZE, "%lu\n",
+                                      atomic_long_read(&sess->conn_timeout_errors));
        }
        spin_unlock_bh(&se_nacl->nacl_sess_lock);
 

diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index f2de28e..45b8fd1 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -980,7 +980,7 @@ static void iscsit_handle_nopin_response_timeout(unsigned long data)
                tiqn->sess_err_stats.last_sess_failure_type =
                                ISCSI_SESS_ERR_CXN_TIMEOUT;
                tiqn->sess_err_stats.cxn_timeout_errors++;
-               conn->sess->conn_timeout_errors++;
+               atomic_long_inc(&conn->sess->conn_timeout_errors);
                spin_unlock_bh(&tiqn->sess_err_stats.lock);
        }
        }