diff options
| author | Don Brace <don.brace@pmcs.com> | 2015-01-23 23:43:46 +0100 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2015-02-02 18:57:41 +0100 |
| commit | 34f0c6277c686b191936cc321faebd15b28f9ece (patch) | |
| tree | f2ef7d5a9f24993e1b6bd86ac667ae31d3ecb289 /drivers/scsi | |
| parent | hpsa: optimize cmd_alloc function by remembering last allocation (diff) | |
| download | linux-34f0c6277c686b191936cc321faebd15b28f9ece.tar.xz linux-34f0c6277c686b191936cc321faebd15b28f9ece.zip | |
hpsa: count passthru cmds with atomics, not a spin locked int
Performance enhancement. Remove spin_locks from the driver.
Reviewed-by: Scott Teel <scott.teel@pmcs.com>
Signed-off-by: Don Brace <don.brace@pmcs.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/scsi')
| -rw-r--r-- | drivers/scsi/hpsa.c | 39 | ||||
| -rw-r--r-- | 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 72abcf3bfabf..bae3759e30e2 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 981479a13935..1856445f883a 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 |