[SCSI] iscsi bugfixes: fix r2t handling

The iscsi tcp code can pluck multiple rt2s from the tasks's r2tqueue
in the xmit code. This can result in the task being queued on the xmit queue
but gettting completed at the same time.

This patch fixes the above bug by making the fifo a list so
we always remove the entry on the list del.

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

1 files changed, 38 insertions, 52 deletions

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 7e6e031cc41b..1a8cd20f484f 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -189,6 +189,7 @@ static void iscsi_complete_command(struct iscsi_session *session,
 {
         struct scsi_cmnd *sc = ctask->sc;
 
+        ctask->state = ISCSI_TASK_COMPLETED;
         ctask->sc = NULL;
         list_del_init(&ctask->running);
         __kfifo_put(session->cmdpool.queue, (void*)&ctask, sizeof(void*));
@@ -568,20 +569,24 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
         }
 
         /* process command queue */
-        while (__kfifo_get(conn->xmitqueue, (void*)&conn->ctask,
-                           sizeof(void*))) {
+        spin_lock_bh(&conn->session->lock);
+        while (!list_empty(&conn->xmitqueue)) {
                 /*
                  * iscsi tcp may readd the task to the xmitqueue to send
                  * write data
                  */
-                spin_lock_bh(&conn->session->lock);
-                if (list_empty(&conn->ctask->running))
-                        list_add_tail(&conn->ctask->running, &conn->run_list);
+                conn->ctask = list_entry(conn->xmitqueue.next,
+                                         struct iscsi_cmd_task, running);
+                conn->ctask->state = ISCSI_TASK_RUNNING;
+                list_move_tail(conn->xmitqueue.next, &conn->run_list);
                 spin_unlock_bh(&conn->session->lock);
+
                 rc = tt->xmit_cmd_task(conn, conn->ctask);
                 if (rc)
                         goto again;
+                spin_lock_bh(&conn->session->lock);
         }
+        spin_unlock_bh(&conn->session->lock);
         /* done with this ctask */
         conn->ctask = NULL;
 
@@ -691,6 +696,7 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
         sc->SCp.phase = session->age;
         sc->SCp.ptr = (char *)ctask;
 
+        ctask->state = ISCSI_TASK_PENDING;
         ctask->mtask = NULL;
         ctask->conn = conn;
         ctask->sc = sc;
@@ -700,7 +706,7 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
 
         session->tt->init_cmd_task(ctask);
 
-        __kfifo_put(conn->xmitqueue, (void*)&ctask, sizeof(void*));
+        list_add_tail(&ctask->running, &conn->xmitqueue);
         debug_scsi(
                "ctask enq [%s cid %d sc %lx itt 0x%x len %d cmdsn %d win %d]\n",
                 sc->sc_data_direction == DMA_TO_DEVICE ? "write" : "read",
@@ -977,31 +983,27 @@ static int iscsi_exec_abort_task(struct scsi_cmnd *sc,
 /*
  * xmit mutex and session lock must be held
  */
-#define iscsi_remove_task(tasktype)                                     \
-static struct iscsi_##tasktype *                                        \
-iscsi_remove_##tasktype(struct kfifo *fifo, uint32_t itt)               \
-{                                                                       \
-        int i, nr_tasks = __kfifo_len(fifo) / sizeof(void*);            \
-        struct iscsi_##tasktype *task;                                  \
-                                                                        \
-        debug_scsi("searching %d tasks\n", nr_tasks);                   \
-                                                                        \
-        for (i = 0; i < nr_tasks; i++) {                                \
-                __kfifo_get(fifo, (void*)&task, sizeof(void*));         \
-                debug_scsi("check task %u\n", task->itt);               \
-                                                                        \
-                if (task->itt == itt) {                                 \
-                        debug_scsi("matched task\n");                   \
-                        return task;                                    \
-                }                                                       \
-                                                                        \
-                __kfifo_put(fifo, (void*)&task, sizeof(void*));         \
-        }                                                               \
-        return NULL;                                                    \
-}
+static struct iscsi_mgmt_task *
+iscsi_remove_mgmt_task(struct kfifo *fifo, uint32_t itt)
+{
+        int i, nr_tasks = __kfifo_len(fifo) / sizeof(void*);
+        struct iscsi_mgmt_task *task;
+
+        debug_scsi("searching %d tasks\n", nr_tasks);
+
+        for (i = 0; i < nr_tasks; i++) {
+                __kfifo_get(fifo, (void*)&task, sizeof(void*));
+                debug_scsi("check task %u\n", task->itt);
+
+                if (task->itt == itt) {
+                        debug_scsi("matched task\n");
+                        return task;
+                }
 
-iscsi_remove_task(mgmt_task);
-iscsi_remove_task(cmd_task);
+                __kfifo_put(fifo, (void*)&task, sizeof(void*));
+        }
+        return NULL;
+}
 
 static int iscsi_ctask_mtask_cleanup(struct iscsi_cmd_task *ctask)
 {
@@ -1043,7 +1045,6 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
         struct iscsi_cmd_task *ctask = (struct iscsi_cmd_task *)sc->SCp.ptr;
         struct iscsi_conn *conn = ctask->conn;
         struct iscsi_session *session = conn->session;
-        struct iscsi_cmd_task *pending_ctask;
         int rc;
 
         conn->eh_abort_cnt++;
@@ -1071,17 +1072,8 @@ int iscsi_eh_abort(struct scsi_cmnd *sc)
                 goto failed;
         }
 
-        /* check for the easy pending cmd abort */
-        pending_ctask = iscsi_remove_cmd_task(conn->xmitqueue, ctask->itt);
-        if (pending_ctask) {
-                /* iscsi_tcp queues write transfers on the xmitqueue */
-                if (list_empty(&pending_ctask->running)) {
-                        debug_scsi("found pending task\n");
-                        goto success;
-                } else
-                        __kfifo_put(conn->xmitqueue, (void*)&pending_ctask,
-                                    sizeof(void*));
-        }
+        if (ctask->state == ISCSI_TASK_PENDING)
+                goto success;
 
         conn->tmabort_state = TMABORT_INITIAL;
 
@@ -1263,6 +1255,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit,
                 if (cmd_task_size)
                         ctask->dd_data = &ctask[1];
                 ctask->itt = cmd_i;
+                INIT_LIST_HEAD(&ctask->running);
         }
 
         spin_lock_init(&session->lock);
@@ -1282,6 +1275,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit,
                 if (mgmt_task_size)
                         mtask->dd_data = &mtask[1];
                 mtask->itt = ISCSI_MGMT_ITT_OFFSET + cmd_i;
+                INIT_LIST_HEAD(&mtask->running);
         }
 
         if (scsi_add_host(shost, NULL))
@@ -1361,12 +1355,7 @@ iscsi_conn_setup(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
         conn->tmabort_state = TMABORT_INITIAL;
         INIT_LIST_HEAD(&conn->run_list);
         INIT_LIST_HEAD(&conn->mgmt_run_list);
-
-        /* initialize general xmit PDU commands queue */
-        conn->xmitqueue = kfifo_alloc(session->cmds_max * sizeof(void*),
-                                        GFP_KERNEL, NULL);
-        if (conn->xmitqueue == ERR_PTR(-ENOMEM))
-                goto xmitqueue_alloc_fail;
+        INIT_LIST_HEAD(&conn->xmitqueue);
 
         /* initialize general immediate & non-immediate PDU commands queue */
         conn->immqueue = kfifo_alloc(session->mgmtpool_max * sizeof(void*),
@@ -1410,8 +1399,6 @@ login_mtask_alloc_fail:
 mgmtqueue_alloc_fail:
         kfifo_free(conn->immqueue);
 immqueue_alloc_fail:
-        kfifo_free(conn->xmitqueue);
-xmitqueue_alloc_fail:
         iscsi_destroy_conn(cls_conn);
         return NULL;
 }
@@ -1489,7 +1476,6 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
                 session->cmdsn = session->max_cmdsn = session->exp_cmdsn = 1;
         spin_unlock_bh(&session->lock);
 
-        kfifo_free(conn->xmitqueue);
         kfifo_free(conn->immqueue);
         kfifo_free(conn->mgmtqueue);
 
@@ -1572,7 +1558,7 @@ static void fail_all_commands(struct iscsi_conn *conn)
         struct iscsi_cmd_task *ctask, *tmp;
 
         /* flush pending */
-        while (__kfifo_get(conn->xmitqueue, (void*)&ctask, sizeof(void*))) {
+        list_for_each_entry_safe(ctask, tmp, &conn->xmitqueue, running) {
                 debug_scsi("failing pending sc %p itt 0x%x\n", ctask->sc,
                            ctask->itt);
                 fail_command(conn, ctask, DID_BUS_BUSY << 16);