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skd: Switch to block layer timeout mechanism
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Remove the timeout slot variables and rely on the block layer to
detect request timeouts.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Bart Van Assche authored and Jens Axboe committed Aug 18, 2017
1 parent ca33dd9 commit a74d5b7
Showing 1 changed file with 31 additions and 86 deletions.
117 changes: 31 additions & 86 deletions drivers/block/skd_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -105,9 +105,6 @@ MODULE_VERSION(DRV_VERSION "-" DRV_BUILD_ID);
#define SKD_ID_SLOT_MASK 0x00FFu
#define SKD_ID_SLOT_AND_TABLE_MASK 0x03FFu

#define SKD_N_TIMEOUT_SLOT 4u
#define SKD_TIMEOUT_SLOT_MASK 3u

#define SKD_N_MAX_SECTORS 2048u

#define SKD_MAX_RETRIES 2u
Expand All @@ -125,7 +122,6 @@ enum skd_drvr_state {
SKD_DRVR_STATE_ONLINE,
SKD_DRVR_STATE_PAUSING,
SKD_DRVR_STATE_PAUSED,
SKD_DRVR_STATE_DRAINING_TIMEOUT,
SKD_DRVR_STATE_RESTARTING,
SKD_DRVR_STATE_RESUMING,
SKD_DRVR_STATE_STOPPING,
Expand All @@ -142,7 +138,6 @@ enum skd_drvr_state {
#define SKD_WAIT_BOOT_TIMO SKD_TIMER_SECONDS(90u)
#define SKD_STARTING_TIMO SKD_TIMER_SECONDS(8u)
#define SKD_RESTARTING_TIMO SKD_TIMER_MINUTES(4u)
#define SKD_DRAINING_TIMO SKD_TIMER_SECONDS(6u)
#define SKD_BUSY_TIMO SKD_TIMER_MINUTES(20u)
#define SKD_STARTED_BUSY_TIMO SKD_TIMER_SECONDS(60u)
#define SKD_START_WAIT_SECONDS 90u
Expand Down Expand Up @@ -185,7 +180,6 @@ struct skd_request_context {

u8 flush_cmd;

u32 timeout_stamp;
enum dma_data_direction data_dir;
struct scatterlist *sg;
u32 n_sg;
Expand Down Expand Up @@ -252,8 +246,6 @@ struct skd_device {
u32 num_fitmsg_context;
u32 num_req_context;

atomic_t timeout_slot[SKD_N_TIMEOUT_SLOT];
atomic_t timeout_stamp;
struct skd_fitmsg_context *skmsg_table;

struct skd_special_context internal_skspcl;
Expand Down Expand Up @@ -464,7 +456,6 @@ static bool skd_fail_all(struct request_queue *q)
case SKD_DRVR_STATE_BUSY:
case SKD_DRVR_STATE_BUSY_IMMINENT:
case SKD_DRVR_STATE_BUSY_ERASE:
case SKD_DRVR_STATE_DRAINING_TIMEOUT:
return false;

case SKD_DRVR_STATE_BUSY_SANITIZE:
Expand Down Expand Up @@ -492,7 +483,6 @@ static void skd_process_request(struct request *req, bool last)
u32 count;
int data_dir;
__be64 be_dmaa;
u32 timo_slot;
int flush, fua;

WARN_ONCE(tag >= skd_max_queue_depth, "%#x > %#x (nr_requests = %lu)\n",
Expand Down Expand Up @@ -577,13 +567,6 @@ static void skd_process_request(struct request *req, bool last)
skmsg->length += sizeof(struct skd_scsi_request);
fmh->num_protocol_cmds_coalesced++;

/*
* Update the active request counts.
* Capture the timeout timestamp.
*/
skreq->timeout_stamp = atomic_read(&skdev->timeout_stamp);
timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK;
atomic_inc(&skdev->timeout_slot[timo_slot]);
atomic_inc(&skdev->in_flight);
dev_dbg(&skdev->pdev->dev, "req=0x%x busy=%d\n", skreq->id,
atomic_read(&skdev->in_flight));
Expand Down Expand Up @@ -617,6 +600,16 @@ static blk_status_t skd_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
return BLK_STS_OK;
}

static enum blk_eh_timer_return skd_timed_out(struct request *req)
{
struct skd_device *skdev = req->q->queuedata;

dev_err(&skdev->pdev->dev, "request with tag %#x timed out\n",
blk_mq_unique_tag(req));

return BLK_EH_HANDLED;
}

static void skd_end_request(struct skd_device *skdev, struct request *req,
blk_status_t error)
{
Expand All @@ -635,6 +628,18 @@ static void skd_end_request(struct skd_device *skdev, struct request *req,
blk_mq_end_request(req, error);
}

/* Only called in case of a request timeout */
static void skd_softirq_done(struct request *req)
{
struct skd_device *skdev = req->q->queuedata;
struct skd_request_context *skreq = blk_mq_rq_to_pdu(req);
unsigned long flags;

spin_lock_irqsave(&skdev->lock, flags);
skd_end_request(skdev, blk_mq_rq_from_pdu(skreq), BLK_STS_TIMEOUT);
spin_unlock_irqrestore(&skdev->lock, flags);
}

static bool skd_preop_sg_list(struct skd_device *skdev,
struct skd_request_context *skreq)
{
Expand Down Expand Up @@ -733,8 +738,6 @@ static void skd_start_queue(struct work_struct *work)
static void skd_timer_tick(ulong arg)
{
struct skd_device *skdev = (struct skd_device *)arg;

u32 timo_slot;
unsigned long reqflags;
u32 state;

Expand All @@ -751,35 +754,9 @@ static void skd_timer_tick(ulong arg)
if (state != skdev->drive_state)
skd_isr_fwstate(skdev);

if (skdev->state != SKD_DRVR_STATE_ONLINE) {
if (skdev->state != SKD_DRVR_STATE_ONLINE)
skd_timer_tick_not_online(skdev);
goto timer_func_out;
}
timo_slot = atomic_inc_return(&skdev->timeout_stamp) &
SKD_TIMEOUT_SLOT_MASK;

/*
* All requests that happened during the previous use of
* this slot should be done by now. The previous use was
* over 7 seconds ago.
*/
if (atomic_read(&skdev->timeout_slot[timo_slot]) == 0)
goto timer_func_out;

/* Something is overdue */
dev_dbg(&skdev->pdev->dev, "found %d timeouts, draining busy=%d\n",
atomic_read(&skdev->timeout_slot[timo_slot]),
atomic_read(&skdev->in_flight));
dev_err(&skdev->pdev->dev, "Overdue IOs (%d), busy %d\n",
atomic_read(&skdev->timeout_slot[timo_slot]),
atomic_read(&skdev->in_flight));

skdev->timer_countdown = SKD_DRAINING_TIMO;
skdev->state = SKD_DRVR_STATE_DRAINING_TIMEOUT;
skdev->timo_slot = timo_slot;
blk_stop_queue(skdev->queue);

timer_func_out:
mod_timer(&skdev->timer, (jiffies + HZ));

spin_unlock_irqrestore(&skdev->lock, reqflags);
Expand Down Expand Up @@ -848,27 +825,6 @@ static void skd_timer_tick_not_online(struct skd_device *skdev)
case SKD_DRVR_STATE_PAUSED:
break;

case SKD_DRVR_STATE_DRAINING_TIMEOUT:
dev_dbg(&skdev->pdev->dev,
"draining busy [%d] tick[%d] qdb[%d] tmls[%d]\n",
skdev->timo_slot, skdev->timer_countdown,
atomic_read(&skdev->in_flight),
atomic_read(&skdev->timeout_slot[skdev->timo_slot]));
/* if the slot has cleared we can let the I/O continue */
if (atomic_read(&skdev->timeout_slot[skdev->timo_slot]) == 0) {
dev_dbg(&skdev->pdev->dev,
"Slot drained, starting queue.\n");
skdev->state = SKD_DRVR_STATE_ONLINE;
blk_start_queue(skdev->queue);
return;
}
if (skdev->timer_countdown > 0) {
skdev->timer_countdown--;
return;
}
skd_restart_device(skdev);
break;

case SKD_DRVR_STATE_RESTARTING:
if (skdev->timer_countdown > 0) {
skdev->timer_countdown--;
Expand Down Expand Up @@ -1495,19 +1451,13 @@ static void skd_resolve_req_exception(struct skd_device *skdev,
static void skd_release_skreq(struct skd_device *skdev,
struct skd_request_context *skreq)
{
u32 timo_slot;

/*
* Decrease the number of active requests.
* Also decrements the count in the timeout slot.
*/
SKD_ASSERT(atomic_read(&skdev->in_flight) > 0);
atomic_dec(&skdev->in_flight);

timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK;
SKD_ASSERT(atomic_read(&skdev->timeout_slot[timo_slot]) > 0);
atomic_dec(&skdev->timeout_slot[timo_slot]);

/*
* Reclaim the skd_request_context
*/
Expand Down Expand Up @@ -1620,7 +1570,6 @@ static int skd_isr_completion_posted(struct skd_device *skdev,
if (skreq->n_sg > 0)
skd_postop_sg_list(skdev, skreq);

/* Mark the FIT msg and timeout slot as free. */
skd_release_skreq(skdev, skreq);

/*
Expand Down Expand Up @@ -1979,13 +1928,8 @@ static void skd_recover_request(struct request *req, void *data, bool reserved)

static void skd_recover_requests(struct skd_device *skdev)
{
int i;

blk_mq_tagset_busy_iter(&skdev->tag_set, skd_recover_request, skdev);

for (i = 0; i < SKD_N_TIMEOUT_SLOT; i++)
atomic_set(&skdev->timeout_slot[i], 0);

atomic_set(&skdev->in_flight, 0);
}

Expand Down Expand Up @@ -2917,6 +2861,10 @@ static int skd_cons_disk(struct skd_device *skdev)
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);

blk_queue_rq_timeout(q, 8 * HZ);
blk_queue_rq_timed_out(q, skd_timed_out);
blk_queue_softirq_done(q, skd_softirq_done);

spin_lock_irqsave(&skdev->lock, flags);
dev_dbg(&skdev->pdev->dev, "stopping queue\n");
blk_mq_stop_hw_queues(skdev->queue);
Expand Down Expand Up @@ -3561,8 +3509,6 @@ const char *skd_skdev_state_to_str(enum skd_drvr_state state)
return "PAUSING";
case SKD_DRVR_STATE_PAUSED:
return "PAUSED";
case SKD_DRVR_STATE_DRAINING_TIMEOUT:
return "DRAINING_TIMEOUT";
case SKD_DRVR_STATE_RESTARTING:
return "RESTARTING";
case SKD_DRVR_STATE_RESUMING:
Expand Down Expand Up @@ -3616,9 +3562,8 @@ static void skd_log_skdev(struct skd_device *skdev, const char *event)
dev_dbg(&skdev->pdev->dev, " busy=%d limit=%d dev=%d lowat=%d\n",
atomic_read(&skdev->in_flight), skdev->cur_max_queue_depth,
skdev->dev_max_queue_depth, skdev->queue_low_water_mark);
dev_dbg(&skdev->pdev->dev, " timestamp=0x%x cycle=%d cycle_ix=%d\n",
atomic_read(&skdev->timeout_stamp), skdev->skcomp_cycle,
skdev->skcomp_ix);
dev_dbg(&skdev->pdev->dev, " cycle=%d cycle_ix=%d\n",
skdev->skcomp_cycle, skdev->skcomp_ix);
}

static void skd_log_skreq(struct skd_device *skdev,
Expand All @@ -3632,8 +3577,8 @@ static void skd_log_skreq(struct skd_device *skdev,
dev_dbg(&skdev->pdev->dev, " state=%s(%d) id=0x%04x fitmsg=0x%04x\n",
skd_skreq_state_to_str(skreq->state), skreq->state, skreq->id,
skreq->fitmsg_id);
dev_dbg(&skdev->pdev->dev, " timo=0x%x sg_dir=%d n_sg=%d\n",
skreq->timeout_stamp, skreq->data_dir, skreq->n_sg);
dev_dbg(&skdev->pdev->dev, " sg_dir=%d n_sg=%d\n",
skreq->data_dir, skreq->n_sg);

dev_dbg(&skdev->pdev->dev,
"req=%p lba=%u(0x%x) count=%u(0x%x) dir=%d\n", req, lba, lba,
Expand Down

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