scsi_transport_srp: Introduce srp_wait_for_queuecommand()

Introduce the helper function srp_wait_for_queuecommand().
Move the definition of scsi_request_fn_active(). Add a comment
above srp_wait_for_queuecommand() that support for scsi-mq needs
to be added.

This patch does not change any functionality. A second call to
srp_wait_for_queuecommand() will be introduced in the next patch.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: James Bottomley <JBottomley@Odin.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.13
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index ae45bd99baed72662b1c528aef97f3b49e9aeb6a..e05cd7e2d6d337cde420cf296e278e14d33a4edd 100644 (file)
--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -396,6 +396,36 @@ static void srp_reconnect_work(struct work_struct *work)
        }
 }
 
+/**
+ * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
+ * @shost: SCSI host for which to count the number of scsi_request_fn() callers.
+ *
+ * To do: add support for scsi-mq in this function.
+ */
+static int scsi_request_fn_active(struct Scsi_Host *shost)
+{
+       struct scsi_device *sdev;
+       struct request_queue *q;
+       int request_fn_active = 0;
+
+       shost_for_each_device(sdev, shost) {
+               q = sdev->request_queue;
+
+               spin_lock_irq(q->queue_lock);
+               request_fn_active += q->request_fn_active;
+               spin_unlock_irq(q->queue_lock);
+       }
+
+       return request_fn_active;
+}
+
+/* Wait until ongoing shost->hostt->queuecommand() calls have finished. */
+static void srp_wait_for_queuecommand(struct Scsi_Host *shost)
+{
+       while (scsi_request_fn_active(shost))
+               msleep(20);
+}
+
 static void __rport_fail_io_fast(struct srp_rport *rport)
 {
        struct Scsi_Host *shost = rport_to_shost(rport);
@@ -503,27 +533,6 @@ void srp_start_tl_fail_timers(struct srp_rport *rport)
 }
 EXPORT_SYMBOL(srp_start_tl_fail_timers);
 
-/**
- * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
- * @shost: SCSI host for which to count the number of scsi_request_fn() callers.
- */
-static int scsi_request_fn_active(struct Scsi_Host *shost)
-{
-       struct scsi_device *sdev;
-       struct request_queue *q;
-       int request_fn_active = 0;
-
-       shost_for_each_device(sdev, shost) {
-               q = sdev->request_queue;
-
-               spin_lock_irq(q->queue_lock);
-               request_fn_active += q->request_fn_active;
-               spin_unlock_irq(q->queue_lock);
-       }
-
-       return request_fn_active;
-}
-
 /**
  * srp_reconnect_rport() - reconnect to an SRP target port
  * @rport: SRP target port.
@@ -559,8 +568,7 @@ int srp_reconnect_rport(struct srp_rport *rport)
        if (res)
                goto out;
        scsi_target_block(&shost->shost_gendev);
-       while (scsi_request_fn_active(shost))
-               msleep(20);
+       srp_wait_for_queuecommand(shost);
        res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
        pr_debug("%s (state %d): transport.reconnect() returned %d\n",
                 dev_name(&shost->shost_gendev), rport->state, res);