From 34f0c6277c686b191936cc321faebd15b28f9ece Mon Sep 17 00:00:00 2001 From: Don Brace Date: Fri, 23 Jan 2015 16:43:46 -0600 Subject: [PATCH] hpsa: count passthru cmds with atomics, not a spin locked int Performance enhancement. Remove spin_locks from the driver. Reviewed-by: Scott Teel Signed-off-by: Don Brace Signed-off-by: Christoph Hellwig --- 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 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 @@ static int hpsa_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) 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 -- GitLab