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Commit 6fbb2de5 authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
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skd: Convert several per-device scalar variables into atomics 



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: default avatarBart 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: default avatarJens Axboe <axboe@kernel.dk>
parent f18c17c8

drivers/block/skd_main.c

+37 −31
Original line number Diff line number Diff line
@@ -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,