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.h b/drivers/scsi/hpsa.h
index 9ea162d..e16f294 100644
--- a/drivers/scsi/hpsa.h
+++ b/drivers/scsi/hpsa.h
@@ -203,6 +203,7 @@
 	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;