hpsa: Rearrange start_io to avoid one unlock/lock sequence in main io path
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Reviewed-by: Joe Handzik <joseph.t.handzik@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 3e501df..0a30cc2 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -194,7 +194,8 @@
static irqreturn_t do_hpsa_intr_intx(int irq, void *dev_id);
static irqreturn_t do_hpsa_intr_msi(int irq, void *dev_id);
static int hpsa_ioctl(struct scsi_device *dev, int cmd, void *arg);
-static void start_io(struct ctlr_info *h);
+static void lock_and_start_io(struct ctlr_info *h);
+static void start_io(struct ctlr_info *h, unsigned long *flags);
#ifdef CONFIG_COMPAT
static int hpsa_compat_ioctl(struct scsi_device *dev, int cmd, void *arg);
@@ -845,8 +846,8 @@
spin_lock_irqsave(&h->lock, flags);
addQ(&h->reqQ, c);
h->Qdepth++;
+ start_io(h, &flags);
spin_unlock_irqrestore(&h->lock, flags);
- start_io(h);
}
static inline void removeQ(struct CommandList *c)
@@ -5459,13 +5460,12 @@
/* Takes cmds off the submission queue and sends them to the hardware,
* then puts them on the queue of cmds waiting for completion.
+ * Assumes h->lock is held
*/
-static void start_io(struct ctlr_info *h)
+static void start_io(struct ctlr_info *h, unsigned long *flags)
{
struct CommandList *c;
- unsigned long flags;
- spin_lock_irqsave(&h->lock, flags);
while (!list_empty(&h->reqQ)) {
c = list_entry(h->reqQ.next, struct CommandList, list);
/* can't do anything if fifo is full */
@@ -5490,10 +5490,18 @@
h->commands_outstanding++;
/* Tell the controller execute command */
- spin_unlock_irqrestore(&h->lock, flags);
+ spin_unlock_irqrestore(&h->lock, *flags);
h->access.submit_command(h, c);
- spin_lock_irqsave(&h->lock, flags);
+ spin_lock_irqsave(&h->lock, *flags);
}
+}
+
+static void lock_and_start_io(struct ctlr_info *h)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&h->lock, flags);
+ start_io(h, &flags);
spin_unlock_irqrestore(&h->lock, flags);
}
@@ -5561,7 +5569,7 @@
else if (c->cmd_type == CMD_IOCTL_PEND)
complete(c->waiting);
if (unlikely(io_may_be_stalled))
- start_io(h);
+ lock_and_start_io(h);
}
static inline u32 hpsa_tag_contains_index(u32 tag)