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Date: Fri, 20 Apr 2012 10:07:22 -0500
From: "Stephen M. Cameron" <scameron@...rdog.cce.hp.com>
To: james.bottomley@...senpartnership.com
Cc: linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
matthew.gates@...com, stephenmcameron@...il.com, thenzl@...hat.com,
akpm@...ux-foundation.org, mikem@...rdog.cce.hp.com
Subject: [PATCH 12/17] hpsa: refine interrupt handler locking for greater
concurrency
From: Matt Gates <matthew.gates@...com>
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@...com>
Signed-off-by: Stephen M. Cameron <scameron@...rdog.cce.hp.com>
---
drivers/scsi/hpsa.c | 61 +++++++++++++++++++++++++++++++++------------------
drivers/scsi/hpsa.h | 13 +++++++----
2 files changed, 48 insertions(+), 26 deletions(-)
diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 29bbf35..1ec912b 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -532,6 +532,7 @@ static inline u32 next_command(struct ctlr_info *h, u8 q)
{
u32 a;
struct reply_pool *rq = &h->reply_queue[q];
+ unsigned long flags;
if (unlikely(!(h->transMethod & CFGTBL_Trans_Performant)))
return h->access.command_completed(h, q);
@@ -539,7 +540,9 @@ static inline u32 next_command(struct ctlr_info *h, u8 q)
if ((rq->head[rq->current_entry] & 1) == rq->wraparound) {
a = rq->head[rq->current_entry];
rq->current_entry++;
+ spin_lock_irqsave(&h->lock, flags);
h->commands_outstanding--;
+ spin_unlock_irqrestore(&h->lock, flags);
} else {
a = FIFO_EMPTY;
}
@@ -574,8 +577,8 @@ static void enqueue_cmd_and_start_io(struct ctlr_info *h,
spin_lock_irqsave(&h->lock, flags);
addQ(&h->reqQ, c);
h->Qdepth++;
- start_io(h);
spin_unlock_irqrestore(&h->lock, flags);
+ start_io(h);
}
static inline void removeQ(struct CommandList *c)
@@ -2083,9 +2086,8 @@ static int hpsa_scsi_queue_command_lck(struct scsi_cmnd *cmd,
done(cmd);
return 0;
}
- /* Need a lock as this is being allocated from the pool */
- c = cmd_alloc(h);
spin_unlock_irqrestore(&h->lock, flags);
+ c = cmd_alloc(h);
if (c == NULL) { /* trouble... */
dev_err(&h->pdev->dev, "cmd_alloc returned NULL!\n");
return SCSI_MLQUEUE_HOST_BUSY;
@@ -2619,14 +2621,21 @@ static struct CommandList *cmd_alloc(struct ctlr_info *h)
int i;
union u64bit temp64;
dma_addr_t cmd_dma_handle, err_dma_handle;
+ unsigned long flags;
+ spin_lock_irqsave(&h->lock, flags);
do {
i = find_first_zero_bit(h->cmd_pool_bits, h->nr_cmds);
- if (i == h->nr_cmds)
+ if (i == h->nr_cmds) {
+ spin_unlock_irqrestore(&h->lock, flags);
return NULL;
+ }
} while (test_and_set_bit
(i & (BITS_PER_LONG - 1),
h->cmd_pool_bits + (i / BITS_PER_LONG)) != 0);
+ h->nr_allocs++;
+ spin_unlock_irqrestore(&h->lock, flags);
+
c = h->cmd_pool + i;
memset(c, 0, sizeof(*c));
cmd_dma_handle = h->cmd_pool_dhandle
@@ -2635,7 +2644,6 @@ static struct CommandList *cmd_alloc(struct ctlr_info *h)
memset(c->err_info, 0, sizeof(*c->err_info));
err_dma_handle = h->errinfo_pool_dhandle
+ i * sizeof(*c->err_info);
- h->nr_allocs++;
c->cmdindex = i;
@@ -2691,11 +2699,14 @@ static struct CommandList *cmd_special_alloc(struct ctlr_info *h)
static void cmd_free(struct ctlr_info *h, struct CommandList *c)
{
int i;
+ unsigned long flags;
i = c - h->cmd_pool;
+ spin_lock_irqsave(&h->lock, flags);
clear_bit(i & (BITS_PER_LONG - 1),
h->cmd_pool_bits + (i / BITS_PER_LONG));
h->nr_frees++;
+ spin_unlock_irqrestore(&h->lock, flags);
}
static void cmd_special_free(struct ctlr_info *h, struct CommandList *c)
@@ -3299,7 +3310,9 @@ static void __iomem *remap_pci_mem(ulong base, ulong size)
static void start_io(struct ctlr_info *h)
{
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 */
@@ -3312,12 +3325,23 @@ static void start_io(struct ctlr_info *h)
removeQ(c);
h->Qdepth--;
- /* Tell the controller execute command */
- h->access.submit_command(h, c);
-
/* Put job onto the completed Q */
addQ(&h->cmpQ, c);
+
+ /* Must increment commands_outstanding before unlocking
+ * and submitting to avoid race checking for fifo full
+ * condition.
+ */
+ h->commands_outstanding++;
+ if (h->commands_outstanding > h->max_outstanding)
+ h->max_outstanding = h->commands_outstanding;
+
+ /* Tell the controller execute command */
+ spin_unlock_irqrestore(&h->lock, flags);
+ h->access.submit_command(h, c);
+ spin_lock_irqsave(&h->lock, flags);
}
+ spin_unlock_irqrestore(&h->lock, flags);
}
static inline unsigned long get_next_completion(struct ctlr_info *h, u8 q)
@@ -3348,7 +3372,11 @@ static inline int bad_tag(struct ctlr_info *h, u32 tag_index,
static inline void finish_cmd(struct CommandList *c)
{
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->h->lock, flags);
removeQ(c);
+ spin_unlock_irqrestore(&c->h->lock, flags);
if (likely(c->cmd_type == CMD_SCSI))
complete_scsi_command(c);
else if (c->cmd_type == CMD_IOCTL_PEND)
@@ -3395,14 +3423,18 @@ static inline void process_nonindexed_cmd(struct ctlr_info *h,
{
u32 tag;
struct CommandList *c = NULL;
+ unsigned long flags;
tag = hpsa_tag_discard_error_bits(h, raw_tag);
+ spin_lock_irqsave(&h->lock, flags);
list_for_each_entry(c, &h->cmpQ, list) {
if ((c->busaddr & 0xFFFFFFE0) == (tag & 0xFFFFFFE0)) {
+ spin_unlock_irqrestore(&h->lock, flags);
finish_cmd(c);
return;
}
}
+ spin_unlock_irqrestore(&h->lock, flags);
bad_tag(h, h->nr_cmds + 1, raw_tag);
}
@@ -3439,7 +3471,6 @@ static irqreturn_t hpsa_intx_discard_completions(int irq, void *queue)
{
struct ctlr_info *h = queue_to_hba(queue);
u8 q = *(u8 *) queue;
- unsigned long flags;
u32 raw_tag;
if (ignore_bogus_interrupt(h))
@@ -3447,47 +3478,39 @@ static irqreturn_t hpsa_intx_discard_completions(int irq, void *queue)
if (interrupt_not_for_us(h))
return IRQ_NONE;
- spin_lock_irqsave(&h->lock, flags);
h->last_intr_timestamp = get_jiffies_64();
while (interrupt_pending(h)) {
raw_tag = get_next_completion(h, q);
while (raw_tag != FIFO_EMPTY)
raw_tag = next_command(h, q);
}
- spin_unlock_irqrestore(&h->lock, flags);
return IRQ_HANDLED;
}
static irqreturn_t hpsa_msix_discard_completions(int irq, void *queue)
{
struct ctlr_info *h = queue_to_hba(queue);
- unsigned long flags;
u32 raw_tag;
u8 q = *(u8 *) queue;
if (ignore_bogus_interrupt(h))
return IRQ_NONE;
- spin_lock_irqsave(&h->lock, flags);
-
h->last_intr_timestamp = get_jiffies_64();
raw_tag = get_next_completion(h, q);
while (raw_tag != FIFO_EMPTY)
raw_tag = next_command(h, q);
- spin_unlock_irqrestore(&h->lock, flags);
return IRQ_HANDLED;
}
static irqreturn_t do_hpsa_intr_intx(int irq, void *queue)
{
struct ctlr_info *h = queue_to_hba((u8 *) queue);
- unsigned long flags;
u32 raw_tag;
u8 q = *(u8 *) queue;
if (interrupt_not_for_us(h))
return IRQ_NONE;
- spin_lock_irqsave(&h->lock, flags);
h->last_intr_timestamp = get_jiffies_64();
while (interrupt_pending(h)) {
raw_tag = get_next_completion(h, q);
@@ -3499,18 +3522,15 @@ static irqreturn_t do_hpsa_intr_intx(int irq, void *queue)
raw_tag = next_command(h, q);
}
}
- spin_unlock_irqrestore(&h->lock, flags);
return IRQ_HANDLED;
}
static irqreturn_t do_hpsa_intr_msi(int irq, void *queue)
{
struct ctlr_info *h = queue_to_hba(queue);
- unsigned long flags;
u32 raw_tag;
u8 q = *(u8 *) queue;
- spin_lock_irqsave(&h->lock, flags);
h->last_intr_timestamp = get_jiffies_64();
raw_tag = get_next_completion(h, q);
while (raw_tag != FIFO_EMPTY) {
@@ -3520,7 +3540,6 @@ static irqreturn_t do_hpsa_intr_msi(int irq, void *queue)
process_nonindexed_cmd(h, raw_tag);
raw_tag = next_command(h, q);
}
- spin_unlock_irqrestore(&h->lock, flags);
return IRQ_HANDLED;
}
diff --git a/drivers/scsi/hpsa.h b/drivers/scsi/hpsa.h
index 486a7c0..79c36aa 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)
--
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