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skd: Convert several per-device scalar variables into atomics

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Convert the per-device scalar variables that are protected by the
queue lock into atomics such that it becomes safe to access these
variables without holding the queue lock.

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>
This commit is contained in:
Bart Van Assche 2017-08-17 13:13:27 -07:00 committed by Jens Axboe
parent f18c17c889
commit 6fbb2de5c9
1 changed files with 37 additions and 31 deletions
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68
drivers/block/skd_main.c
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@ -243,7 +243,7 @@ struct skd_device {
enum skd_drvr_state state;
u32 drive_state;
u32 in_flight;
atomic_t in_flight;
u32 cur_max_queue_depth;
u32 queue_low_water_mark;
u32 dev_max_queue_depth;
@ -251,8 +251,8 @@ struct skd_device {
u32 num_fitmsg_context;
u32 num_req_context;
u32 timeout_slot[SKD_N_TIMEOUT_SLOT];
u32 timeout_stamp;
atomic_t timeout_slot[SKD_N_TIMEOUT_SLOT];
atomic_t timeout_stamp;
struct skd_fitmsg_context *skmsg_table;
struct skd_request_context *skreq_table;
@ -517,7 +517,8 @@ static void skd_request_fn(struct request_queue *q)
}
if (blk_queue_stopped(skdev->queue)) {
if (skdev->in_flight >= skdev->queue_low_water_mark)
if (atomic_read(&skdev->in_flight) >=
skdev->queue_low_water_mark)
/* There is still some kind of shortage */
return;
@ -559,9 +560,11 @@ static void skd_request_fn(struct request_queue *q)
/* At this point we know there is a request */
/* Are too many requets already in progress? */
if (skdev->in_flight >= skdev->cur_max_queue_depth) {
if (atomic_read(&skdev->in_flight) >=
skdev->cur_max_queue_depth) {
dev_dbg(&skdev->pdev->dev, "qdepth %d, limit %d\n",
skdev->in_flight, skdev->cur_max_queue_depth);
atomic_read(&skdev->in_flight),
skdev->cur_max_queue_depth);
break;
}
@ -647,12 +650,12 @@ static void skd_request_fn(struct request_queue *q)
* Update the active request counts.
* Capture the timeout timestamp.
*/
skreq->timeout_stamp = skdev->timeout_stamp;
skreq->timeout_stamp = atomic_read(&skdev->timeout_stamp);
timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK;
skdev->timeout_slot[timo_slot]++;
skdev->in_flight++;
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,
skdev->in_flight);
atomic_read(&skdev->in_flight));
/*
* If the FIT msg buffer is full send it.
@ -805,22 +808,24 @@ static void skd_timer_tick(ulong arg)
skd_timer_tick_not_online(skdev);
goto timer_func_out;
}
skdev->timeout_stamp++;
timo_slot = skdev->timeout_stamp & SKD_TIMEOUT_SLOT_MASK;
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 (skdev->timeout_slot[timo_slot] == 0)
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",
skdev->timeout_slot[timo_slot], skdev->in_flight);
atomic_read(&skdev->timeout_slot[timo_slot]),
atomic_read(&skdev->in_flight));
dev_err(&skdev->pdev->dev, "Overdue IOs (%d), busy %d\n",
skdev->timeout_slot[timo_slot], skdev->in_flight);
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;
@ -900,10 +905,10 @@ static void skd_timer_tick_not_online(struct skd_device *skdev)
dev_dbg(&skdev->pdev->dev,
"draining busy [%d] tick[%d] qdb[%d] tmls[%d]\n",
skdev->timo_slot, skdev->timer_countdown,
skdev->in_flight,
skdev->timeout_slot[skdev->timo_slot]);
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 (skdev->timeout_slot[skdev->timo_slot] == 0) {
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;
@ -1310,7 +1315,7 @@ static void skd_send_fitmsg(struct skd_device *skdev,
u64 qcmd;
dev_dbg(&skdev->pdev->dev, "dma address 0x%llx, busy=%d\n",
skmsg->mb_dma_address, skdev->in_flight);
skmsg->mb_dma_address, atomic_read(&skdev->in_flight));
dev_dbg(&skdev->pdev->dev, "msg_buf %p\n", skmsg->msg_buf);
qcmd = skmsg->mb_dma_address;
@ -1550,12 +1555,12 @@ static void skd_release_skreq(struct skd_device *skdev,
* Decrease the number of active requests.
* Also decrements the count in the timeout slot.
*/
SKD_ASSERT(skdev->in_flight > 0);
skdev->in_flight -= 1;
SKD_ASSERT(atomic_read(&skdev->in_flight) > 0);
atomic_dec(&skdev->in_flight);
timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK;
SKD_ASSERT(skdev->timeout_slot[timo_slot] > 0);
skdev->timeout_slot[timo_slot] -= 1;
SKD_ASSERT(atomic_read(&skdev->timeout_slot[timo_slot]) > 0);
atomic_dec(&skdev->timeout_slot[timo_slot]);
/*
* Reset backpointer
@ -1615,8 +1620,8 @@ static int skd_isr_completion_posted(struct skd_device *skdev,
dev_dbg(&skdev->pdev->dev,
"cycle=%d ix=%d got cycle=%d cmdctxt=0x%x stat=%d busy=%d rbytes=0x%x proto=%d\n",
skdev->skcomp_cycle, skdev->skcomp_ix, cmp_cycle,
cmp_cntxt, cmp_status, skdev->in_flight, cmp_bytes,
skdev->proto_ver);
cmp_cntxt, cmp_status, atomic_read(&skdev->in_flight),
cmp_bytes, skdev->proto_ver);
if (cmp_cycle != skdev->skcomp_cycle) {
dev_dbg(&skdev->pdev->dev, "end of completions\n");
@ -1707,8 +1712,8 @@ static int skd_isr_completion_posted(struct skd_device *skdev,
}
}
if ((skdev->state == SKD_DRVR_STATE_PAUSING)
&& (skdev->in_flight) == 0) {
if (skdev->state == SKD_DRVR_STATE_PAUSING &&
atomic_read(&skdev->in_flight) == 0) {
skdev->state = SKD_DRVR_STATE_PAUSED;
wake_up_interruptible(&skdev->waitq);
}
@ -2053,9 +2058,9 @@ static void skd_recover_requests(struct skd_device *skdev)
}
for (i = 0; i < SKD_N_TIMEOUT_SLOT; i++)
skdev->timeout_slot[i] = 0;
atomic_set(&skdev->timeout_slot[i], 0);
skdev->in_flight = 0;
atomic_set(&skdev->in_flight, 0);
}
static void skd_isr_msg_from_dev(struct skd_device *skdev)
@ -3714,10 +3719,11 @@ static void skd_log_skdev(struct skd_device *skdev, const char *event)
skd_drive_state_to_str(skdev->drive_state), skdev->drive_state,
skd_skdev_state_to_str(skdev->state), skdev->state);
dev_dbg(&skdev->pdev->dev, " busy=%d limit=%d dev=%d lowat=%d\n",
skdev->in_flight, skdev->cur_max_queue_depth,
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",
skdev->timeout_stamp, skdev->skcomp_cycle, skdev->skcomp_ix);
atomic_read(&skdev->timeout_stamp), skdev->skcomp_cycle,
skdev->skcomp_ix);
}
static void skd_log_skreq(struct skd_device *skdev,