Performance enhancement. Remove spin_locks from the driver.
Reviewed-by: Scott Teel <scott.t...@pmcs.com>
Signed-off-by: Don Brace <don.br...@pmcs.com>
---
drivers/scsi/hpsa.c | 39 +++++----------------------------------
drivers/scsi/hpsa.h | 3 +--
2 files changed, 6 insertions(+), 36 deletions(-)
diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 72abcf3..bae3759 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -5105,35 +5105,6 @@ static void check_ioctl_unit_attention(struct ctlr_info
*h,
(void) check_for_unit_attention(h, c);
}
-static int increment_passthru_count(struct ctlr_info *h)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&h->passthru_count_lock, flags);
- if (h->passthru_count >= HPSA_MAX_CONCURRENT_PASSTHRUS) {
- spin_unlock_irqrestore(&h->passthru_count_lock, flags);
- return -1;
- }
- h->passthru_count++;
- spin_unlock_irqrestore(&h->passthru_count_lock, flags);
- return 0;
-}
-
-static void decrement_passthru_count(struct ctlr_info *h)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&h->passthru_count_lock, flags);
- if (h->passthru_count <= 0) {
- spin_unlock_irqrestore(&h->passthru_count_lock, flags);
- /* not expecting to get here. */
- dev_warn(&h->pdev->dev, "Bug detected, passthru_count seems to
be incorrect.\n");
- return;
- }
- h->passthru_count--;
- spin_unlock_irqrestore(&h->passthru_count_lock, flags);
-}
-
/*
* ioctl
*/
@@ -5156,16 +5127,16 @@ static int hpsa_ioctl(struct scsi_device *dev, int cmd,
void __user *arg)
case CCISS_GETDRIVVER:
return hpsa_getdrivver_ioctl(h, argp);
case CCISS_PASSTHRU:
- if (increment_passthru_count(h))
+ if (atomic_dec_if_positive(&h->passthru_cmds_avail) < 0)
return -EAGAIN;
rc = hpsa_passthru_ioctl(h, argp);
- decrement_passthru_count(h);
+ atomic_inc(&h->passthru_cmds_avail);
return rc;
case CCISS_BIG_PASSTHRU:
- if (increment_passthru_count(h))
+ if (atomic_dec_if_positive(&h->passthru_cmds_avail) < 0)
return -EAGAIN;
rc = hpsa_big_passthru_ioctl(h, argp);
- decrement_passthru_count(h);
+ atomic_inc(&h->passthru_cmds_avail);
return rc;
default:
return -ENOTTY;
@@ -6852,7 +6823,7 @@ reinit_after_soft_reset:
spin_lock_init(&h->lock);
spin_lock_init(&h->offline_device_lock);
spin_lock_init(&h->scan_lock);
- spin_lock_init(&h->passthru_count_lock);
+ atomic_set(&h->passthru_cmds_avail, HPSA_MAX_CONCURRENT_PASSTHRUS);
h->resubmit_wq = alloc_workqueue("hpsa", WQ_MEM_RECLAIM, 0);
if (!h->resubmit_wq) {
diff --git a/drivers/scsi/hpsa.h b/drivers/scsi/hpsa.h
index 981479a..1856445 100644
--- a/drivers/scsi/hpsa.h
+++ b/drivers/scsi/hpsa.h
@@ -183,8 +183,7 @@ struct ctlr_info {
/* cap concurrent passthrus at some reasonable maximum */
#define HPSA_MAX_CONCURRENT_PASSTHRUS (10)
- spinlock_t passthru_count_lock; /* protects passthru_count */
- int passthru_count;
+ atomic_t passthru_cmds_avail;
/*
* Performant mode completion buffers
--
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