[SCSI] libiscsi: fix cmd seqeunce number checking

We should not be checking the cmd windown for just handling r2t responses.
And if the window closes in on us, always have scsi-ml requeue the command
from our queuecommand function.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 271a2d6..5606d1e 100644 (file)
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -596,9 +596,16 @@ static void iscsi_prep_mtask(struct iscsi_conn *conn,
        nop->cmdsn = cpu_to_be32(session->cmdsn);
        if (hdr->itt != RESERVED_ITT) {
                hdr->itt = build_itt(mtask->itt, conn->id, session->age);
+               /*
+                * TODO: We always use immediate, so we never hit this.
+                * If we start to send tmfs or nops as non-immediate then
+                * we should start checking the cmdsn numbers for mgmt tasks.
+                */
                if (conn->c_stage == ISCSI_CONN_STARTED &&
-                   !(hdr->opcode & ISCSI_OP_IMMEDIATE))
+                   !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
+                       session->queued_cmdsn++;
                        session->cmdsn++;
+               }
        }
 
        if (session->tt->init_mgmt_task)
@@ -641,9 +648,11 @@ static int iscsi_check_cmdsn_window_closed(struct iscsi_conn *conn)
        /*
         * Check for iSCSI window and take care of CmdSN wrap-around
         */
-       if (!iscsi_sna_lte(session->cmdsn, session->max_cmdsn)) {
-               debug_scsi("iSCSI CmdSN closed. MaxCmdSN %u CmdSN %u\n",
-                          session->max_cmdsn, session->cmdsn);
+       if (!iscsi_sna_lte(session->queued_cmdsn, session->max_cmdsn)) {
+               debug_scsi("iSCSI CmdSN closed. ExpCmdSn %u MaxCmdSN %u "
+                          "CmdSN %u/%u\n", session->exp_cmdsn,
+                          session->max_cmdsn, session->cmdsn,
+                          session->queued_cmdsn);
                return -ENOSPC;
        }
        return 0;
@@ -722,11 +731,6 @@ check_mgmt:
 
        /* process command queue */
        while (!list_empty(&conn->xmitqueue)) {
-               rc = iscsi_check_cmdsn_window_closed(conn);
-               if (rc) {
-                       spin_unlock_bh(&conn->session->lock);
-                       return rc;
-               }
                /*
                 * iscsi tcp may readd the task to the xmitqueue to send
                 * write data
@@ -834,12 +838,6 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
                goto fault;
        }
 
-       /*
-        * We check this here and in data xmit, because if we get to the point
-        * that this check is hitting the window then we have enough IO in
-        * flight and enough IO waiting to be transmitted it is better
-        * to let the scsi/block layer queue up.
-        */
        if (iscsi_check_cmdsn_window_closed(conn)) {
                reason = FAILURE_WINDOW_CLOSED;
                goto reject;
@@ -850,6 +848,8 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
                reason = FAILURE_OOM;
                goto reject;
        }
+       session->queued_cmdsn++;
+
        sc->SCp.phase = session->age;
        sc->SCp.ptr = (char *)ctask;
 
@@ -1140,7 +1140,13 @@ static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
        if (!sc)
                return;
 
-       if (ctask->state != ISCSI_TASK_PENDING)
+       if (ctask->state == ISCSI_TASK_PENDING)
+               /*
+                * cmd never made it to the xmit thread, so we should not count
+                * the cmd in the sequencing
+                */
+               conn->session->queued_cmdsn--;
+       else
                conn->session->tt->cleanup_cmd_task(conn, ctask);
        iscsi_ctask_mtask_cleanup(ctask);
 
@@ -1392,7 +1398,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit,
        session->state = ISCSI_STATE_FREE;
        session->mgmtpool_max = ISCSI_MGMT_CMDS_MAX;
        session->cmds_max = cmds_max;
-       session->cmdsn = initial_cmdsn;
+       session->queued_cmdsn = session->cmdsn = initial_cmdsn;
        session->exp_cmdsn = initial_cmdsn + 1;
        session->max_cmdsn = initial_cmdsn + 1;
        session->max_r2t = 1;
@@ -1616,11 +1622,8 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
        kfree(conn->persistent_address);
        __kfifo_put(session->mgmtpool.queue, (void*)&conn->login_mtask,
                    sizeof(void*));
-       if (session->leadconn == conn) {
+       if (session->leadconn == conn)
                session->leadconn = NULL;
-               /* no connections exits.. reset sequencing */
-               session->cmdsn = session->max_cmdsn = session->exp_cmdsn = 1;
-       }
        spin_unlock_bh(&session->lock);
 
        kfifo_free(conn->mgmtqueue);
@@ -1650,6 +1653,7 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
        spin_lock_bh(&session->lock);
        conn->c_stage = ISCSI_CONN_STARTED;
        session->state = ISCSI_STATE_LOGGED_IN;
+       session->queued_cmdsn = session->cmdsn;
 
        switch(conn->stop_stage) {
        case STOP_CONN_RECOVER:

diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 3f631b0..007d442 100644 (file)
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -210,6 +210,9 @@ struct iscsi_session {
        uint32_t                exp_cmdsn;
        uint32_t                max_cmdsn;
 
+       /* This tracks the reqs queued into the initiator */
+       uint32_t                queued_cmdsn;
+
        /* configuration */
        int                     initial_r2t_en;
        unsigned                max_r2t;