scsi: hpsa: limit outstanding rescans

[ Upstream commit 87b9e6aa87d9411f1059aa245c0c79976bc557ac ]

Avoid rescan storms. No need to queue another if one is pending.

Reviewed-by: Scott Benesh <scott.benesh@microsemi.com>
Reviewed-by: Scott Teel <scott.teel@microsemi.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 09f0de8..2feab0f 100644 (file)
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -5254,7 +5254,7 @@ static void hpsa_scan_complete(struct ctlr_info *h)
 
        spin_lock_irqsave(&h->scan_lock, flags);
        h->scan_finished = 1;
-       wake_up_all(&h->scan_wait_queue);
+       wake_up(&h->scan_wait_queue);
        spin_unlock_irqrestore(&h->scan_lock, flags);
 }
 
@@ -5272,11 +5272,23 @@ static void hpsa_scan_start(struct Scsi_Host *sh)
        if (unlikely(lockup_detected(h)))
                return hpsa_scan_complete(h);
 
+       /*
+        * If a scan is already waiting to run, no need to add another
+        */
+       spin_lock_irqsave(&h->scan_lock, flags);
+       if (h->scan_waiting) {
+               spin_unlock_irqrestore(&h->scan_lock, flags);
+               return;
+       }
+
+       spin_unlock_irqrestore(&h->scan_lock, flags);
+
        /* wait until any scan already in progress is finished. */
        while (1) {
                spin_lock_irqsave(&h->scan_lock, flags);
                if (h->scan_finished)
                        break;
+               h->scan_waiting = 1;
                spin_unlock_irqrestore(&h->scan_lock, flags);
                wait_event(h->scan_wait_queue, h->scan_finished);
                /* Note: We don't need to worry about a race between this
@@ -5286,6 +5298,7 @@ static void hpsa_scan_start(struct Scsi_Host *sh)
                 */
        }
        h->scan_finished = 0; /* mark scan as in progress */
+       h->scan_waiting = 0;
        spin_unlock_irqrestore(&h->scan_lock, flags);
 
        if (unlikely(lockup_detected(h)))
@@ -8502,6 +8515,7 @@ reinit_after_soft_reset:
        init_waitqueue_head(&h->event_sync_wait_queue);
        mutex_init(&h->reset_mutex);
        h->scan_finished = 1; /* no scan currently in progress */
+       h->scan_waiting = 0;
 
        pci_set_drvdata(pdev, h);
        h->ndevices = 0;

diff --git a/drivers/scsi/hpsa.h b/drivers/scsi/hpsa.h
index ae5beda..0e60275 100644 (file)
--- a/drivers/scsi/hpsa.h
+++ b/drivers/scsi/hpsa.h
@@ -200,6 +200,7 @@ struct ctlr_info {
        dma_addr_t              errinfo_pool_dhandle;
        unsigned long           *cmd_pool_bits;
        int                     scan_finished;
+       u8                      scan_waiting : 1;
        spinlock_t              scan_lock;
        wait_queue_head_t       scan_wait_queue;