scsi: libfc: do not flood console with messages 'libfc: queue full ...'

When the FCoE sending side becomes congested libfc tries to reduce the
queue depth on the host; however due to the built-in lag before
attempting to ramp down the queue depth _again_ the message log is
flooded with the following message:

	libfc: queue full, reducing can_queue to 512

With this patch the message is printed only once (ie when it's
actually changed).

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Acked-by: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c
index a808e8e..234352d 100644 (file)
--- a/drivers/scsi/libfc/fc_fcp.c
+++ b/drivers/scsi/libfc/fc_fcp.c
@@ -407,11 +407,12 @@ unlock:
  * can_queue. Eventually we will hit the point where we run
  * on all reserved structs.
  */
-static void fc_fcp_can_queue_ramp_down(struct fc_lport *lport)
+static bool fc_fcp_can_queue_ramp_down(struct fc_lport *lport)
 {
        struct fc_fcp_internal *si = fc_get_scsi_internal(lport);
        unsigned long flags;
        int can_queue;
+       bool changed = false;
 
        spin_lock_irqsave(lport->host->host_lock, flags);
 
@@ -427,9 +428,11 @@ static void fc_fcp_can_queue_ramp_down(struct fc_lport *lport)
        if (!can_queue)
                can_queue = 1;
        lport->host->can_queue = can_queue;
+       changed = true;
 
 unlock:
        spin_unlock_irqrestore(lport->host->host_lock, flags);
+       return changed;
 }
 
 /*
@@ -1896,11 +1899,11 @@ int fc_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *sc_cmd)
 
        if (!fc_fcp_lport_queue_ready(lport)) {
                if (lport->qfull) {
-                       fc_fcp_can_queue_ramp_down(lport);
-                       shost_printk(KERN_ERR, lport->host,
-                                    "libfc: queue full, "
-                                    "reducing can_queue to %d.\n",
-                                    lport->host->can_queue);
+                       if (fc_fcp_can_queue_ramp_down(lport))
+                               shost_printk(KERN_ERR, lport->host,
+                                            "libfc: queue full, "
+                                            "reducing can_queue to %d.\n",
+                                            lport->host->can_queue);
                }
                rc = SCSI_MLQUEUE_HOST_BUSY;
                goto out;