[PATCH 4.4 041/115] scsi: hpsa: limit outstanding rescans

Greg Kroah-Hartman
2017-12-18T15:54:03Z

From: Don Brace <don.brace@microsemi.com>

[ 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>
---
drivers/scsi/hpsa.c | 16 +++++++++++++++-
drivers/scsi/hpsa.h | 1 +
2 files changed, 16 insertions(+), 1 deletion(-)

--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -5254,7 +5254,7 @@ static void hpsa_scan_complete(struct ct

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_
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_
*/
}
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;
--- 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;