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[SCSI] hpsa: refine interrupt handler locking for greater concurrency
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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@hp.com>
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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Matt Gates authored and James Bottomley committed May 10, 2012
1 parent 254f796 commit e16a33a
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Showing 2 changed files with 48 additions and 26 deletions.
61 changes: 40 additions & 21 deletions drivers/scsi/hpsa.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -533,14 +533,17 @@ 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);

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;
}
Expand Down Expand Up @@ -575,8 +578,8 @@ 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)
Expand Down Expand Up @@ -2091,9 +2094,8 @@ 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;
Expand Down Expand Up @@ -2627,14 +2629,21 @@ 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
Expand All @@ -2643,7 +2652,6 @@ 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;

Expand Down Expand Up @@ -2699,11 +2707,14 @@ 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)
Expand Down Expand Up @@ -3307,7 +3318,9 @@ 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 */
Expand All @@ -3320,12 +3333,23 @@ 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)
Expand Down Expand Up @@ -3356,7 +3380,11 @@ 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)
Expand Down Expand Up @@ -3403,14 +3431,18 @@ 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);
}

Expand Down Expand Up @@ -3447,55 +3479,46 @@ 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))
return IRQ_NONE;

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);
Expand All @@ -3507,18 +3530,15 @@ 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) {
Expand All @@ -3528,7 +3548,6 @@ 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;
}

Expand Down
13 changes: 8 additions & 5 deletions drivers/scsi/hpsa.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

/*
Expand Down Expand Up @@ -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)) {
Expand All @@ -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;
}
Expand Down Expand Up @@ -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)
Expand Down

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