[SCSI] hpsa: refine interrupt handler locking for greater concurrency

Use spinlocks with finer granularity in the submission and
completion paths to allow concurrent execution for multiple
reply queues.  In particular, do not hold a spin lock while
submitting a request to the device, nor during most of the
interrupt handler.

Signed-off-by: Matt Gates <matthew.gates@hp.com>
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/scsi/hpsa.h b/drivers/scsi/hpsa.h
index 486a7c099246..79c36aaa2a37 100644
--- a/drivers/scsi/hpsa.h
+++ b/drivers/scsi/hpsa.h
@@ -246,9 +246,6 @@ static void SA5_submit_command(struct ctlr_info *h,
                 c->Header.Tag.lower);
         writel(c->busaddr, h->vaddr + SA5_REQUEST_PORT_OFFSET);
         (void) readl(h->vaddr + SA5_SCRATCHPAD_OFFSET);
-        h->commands_outstanding++;
-        if (h->commands_outstanding > h->max_outstanding)
-                h->max_outstanding = h->commands_outstanding;
 }
 
 /*
@@ -287,7 +284,7 @@ static void SA5_performant_intr_mask(struct ctlr_info *h, unsigned long val)
 static unsigned long SA5_performant_completed(struct ctlr_info *h, u8 q)
 {
         struct reply_pool *rq = &h->reply_queue[q];
-        unsigned long register_value = FIFO_EMPTY;
+        unsigned long flags, register_value = FIFO_EMPTY;
 
         /* msi auto clears the interrupt pending bit. */
         if (!(h->msi_vector || h->msix_vector)) {
@@ -305,7 +302,9 @@ static unsigned long SA5_performant_completed(struct ctlr_info *h, u8 q)
         if ((rq->head[rq->current_entry] & 1) == rq->wraparound) {
                 register_value = rq->head[rq->current_entry];
                 rq->current_entry++;
+                spin_lock_irqsave(&h->lock, flags);
                 h->commands_outstanding--;
+                spin_unlock_irqrestore(&h->lock, flags);
         } else {
                 register_value = FIFO_EMPTY;
         }
@@ -338,9 +337,13 @@ static unsigned long SA5_completed(struct ctlr_info *h,
 {
         unsigned long register_value
                 = readl(h->vaddr + SA5_REPLY_PORT_OFFSET);
+        unsigned long flags;
 
-        if (register_value != FIFO_EMPTY)
+        if (register_value != FIFO_EMPTY) {
+                spin_lock_irqsave(&h->lock, flags);
                 h->commands_outstanding--;
+                spin_unlock_irqrestore(&h->lock, flags);
+        }
 
 #ifdef HPSA_DEBUG
         if (register_value != FIFO_EMPTY)