[PATCH] libfc: do not flood console with messages 'libfc: queue full ...'

Hannes Reinecke
2017-04-27T14:25:08Z

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 messages

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>
---
drivers/scsi/libfc/fc_fcp.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c
index a808e8e..234352da 100644
--- a/drivers/scsi/libfc/fc_fcp.c
+++ b/drivers/scsi/libfc/fc_fcp.c
@@ -407,11 +407,12 @@ static void fc_fcp_can_queue_ramp_up(struct fc_lport *lport)
* 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;
--
1.8.5.6