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Commit cdf8a6fb authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson
Browse files

mmc: block: Introduce queue semantics 



Change from viewing the requests in progress as 'current' and 'previous',
to viewing them as a queue. The current request is allocated to the first
free slot. The presence of incomplete requests is determined from the
count (mq->qcnt) of entries in the queue. Non-read-write requests (i.e.
discards and flushes) are not added to the queue at all and require no
special handling. Also no special handling is needed for the
MMC_BLK_NEW_REQUEST case.

As well as allowing an arbitrarily sized queue, the queue thread function
is significantly simpler.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 8ddfe07e

drivers/mmc/core/block.c

+41 −25
Original line number Diff line number Diff line
@@ -129,6 +129,13 @@ static inline int mmc_blk_part_switch(struct mmc_card *card, 
				      struct mmc_blk_data *md);

static int get_card_status(struct mmc_card *card, u32 *status, int retries);



static void mmc_blk_requeue(struct request_queue *q, struct request *req)

{

	spin_lock_irq(q->queue_lock);

	blk_requeue_request(q, req);

	spin_unlock_irq(q->queue_lock);

}



static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)

{

	struct mmc_blk_data *md;
@@ -1585,11 +1592,14 @@ static bool mmc_blk_rw_cmd_err(struct mmc_blk_data *md, struct mmc_card *card, 
	return req_pending;

}



static void mmc_blk_rw_cmd_abort(struct mmc_card *card, struct request *req)

static void mmc_blk_rw_cmd_abort(struct mmc_queue *mq, struct mmc_card *card,

				 struct request *req,

				 struct mmc_queue_req *mqrq)

{

	if (mmc_card_removed(card))

		req->rq_flags |= RQF_QUIET;

	while (blk_end_request(req, -EIO, blk_rq_cur_bytes(req)));

	mmc_queue_req_free(mq, mqrq);

}



/**
@@ -1609,6 +1619,7 @@ static void mmc_blk_rw_try_restart(struct mmc_queue *mq, struct request *req, 
	if (mmc_card_removed(mq->card)) {

		req->rq_flags |= RQF_QUIET;

		blk_end_request_all(req, -EIO);

		mmc_queue_req_free(mq, mqrq);

		return;

	}

	/* Else proceed and try to restart the current async request */
@@ -1623,14 +1634,23 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
	struct mmc_blk_request *brq;

	int disable_multi = 0, retry = 0, type, retune_retry_done = 0;

	enum mmc_blk_status status;

	struct mmc_queue_req *mqrq_cur = mq->mqrq_cur;

	struct mmc_queue_req *mqrq_cur = NULL;

	struct mmc_queue_req *mq_rq;

	struct request *old_req;

	struct mmc_async_req *new_areq;

	struct mmc_async_req *old_areq;

	bool req_pending = true;



	if (!new_req && !mq->mqrq_prev->req)

	if (new_req) {

		mqrq_cur = mmc_queue_req_find(mq, new_req);

		if (!mqrq_cur) {

			WARN_ON(1);

			mmc_blk_requeue(mq->queue, new_req);

			new_req = NULL;

		}

	}



	if (!mq->qcnt)

		return;



	do {
@@ -1643,7 +1663,7 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
				!IS_ALIGNED(blk_rq_sectors(new_req), 8)) {

				pr_err("%s: Transfer size is not 4KB sector size aligned\n",

					new_req->rq_disk->disk_name);

				mmc_blk_rw_cmd_abort(card, new_req);

				mmc_blk_rw_cmd_abort(mq, card, new_req, mqrq_cur);

				return;

			}
@@ -1659,8 +1679,6 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
			 * and there is nothing more to do until it is

			 * complete.

			 */

			if (status == MMC_BLK_NEW_REQUEST)

				mq->new_request = true;

			return;

		}
@@ -1693,7 +1711,7 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
				pr_err("%s BUG rq_tot %d d_xfer %d\n",

				       __func__, blk_rq_bytes(old_req),

				       brq->data.bytes_xfered);

				mmc_blk_rw_cmd_abort(card, old_req);

				mmc_blk_rw_cmd_abort(mq, card, old_req, mq_rq);

				return;

			}

			break;
@@ -1701,11 +1719,14 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
			req_pending = mmc_blk_rw_cmd_err(md, card, brq, old_req, req_pending);

			if (mmc_blk_reset(md, card->host, type)) {

				if (req_pending)

					mmc_blk_rw_cmd_abort(card, old_req);

					mmc_blk_rw_cmd_abort(mq, card, old_req, mq_rq);

				else

					mmc_queue_req_free(mq, mq_rq);

				mmc_blk_rw_try_restart(mq, new_req, mqrq_cur);

				return;

			}

			if (!req_pending) {

				mmc_queue_req_free(mq, mq_rq);

				mmc_blk_rw_try_restart(mq, new_req, mqrq_cur);

				return;

			}
@@ -1718,7 +1739,7 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
		case MMC_BLK_ABORT:

			if (!mmc_blk_reset(md, card->host, type))

				break;

			mmc_blk_rw_cmd_abort(card, old_req);

			mmc_blk_rw_cmd_abort(mq, card, old_req, mq_rq);

			mmc_blk_rw_try_restart(mq, new_req, mqrq_cur);

			return;

		case MMC_BLK_DATA_ERR: {
@@ -1728,7 +1749,7 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
			if (!err)

				break;

			if (err == -ENODEV) {

				mmc_blk_rw_cmd_abort(card, old_req);

				mmc_blk_rw_cmd_abort(mq, card, old_req, mq_rq);

				mmc_blk_rw_try_restart(mq, new_req, mqrq_cur);

				return;

			}
@@ -1750,18 +1771,19 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
			req_pending = blk_end_request(old_req, -EIO,

						      brq->data.blksz);

			if (!req_pending) {

				mmc_queue_req_free(mq, mq_rq);

				mmc_blk_rw_try_restart(mq, new_req, mqrq_cur);

				return;

			}

			break;

		case MMC_BLK_NOMEDIUM:

			mmc_blk_rw_cmd_abort(card, old_req);

			mmc_blk_rw_cmd_abort(mq, card, old_req, mq_rq);

			mmc_blk_rw_try_restart(mq, new_req, mqrq_cur);

			return;

		default:

			pr_err("%s: Unhandled return value (%d)",

					old_req->rq_disk->disk_name, status);

			mmc_blk_rw_cmd_abort(card, old_req);

			mmc_blk_rw_cmd_abort(mq, card, old_req, mq_rq);

			mmc_blk_rw_try_restart(mq, new_req, mqrq_cur);

			return;

		}
@@ -1778,6 +1800,8 @@ static void mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *new_req) 
			mq_rq->brq.retune_retry_done = retune_retry_done;

		}

	} while (req_pending);



	mmc_queue_req_free(mq, mq_rq);

}



void mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
@@ -1785,9 +1809,8 @@ void mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
	int ret;

	struct mmc_blk_data *md = mq->blkdata;

	struct mmc_card *card = md->queue.card;

	bool req_is_special = mmc_req_is_special(req);



	if (req && !mq->mqrq_prev->req)

	if (req && !mq->qcnt)

		/* claim host only for the first request */

		mmc_get_card(card);
@@ -1799,20 +1822,19 @@ void mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
		goto out;

	}



	mq->new_request = false;

	if (req && req_op(req) == REQ_OP_DISCARD) {

		/* complete ongoing async transfer before issuing discard */

		if (card->host->areq)

		if (mq->qcnt)

			mmc_blk_issue_rw_rq(mq, NULL);

		mmc_blk_issue_discard_rq(mq, req);

	} else if (req && req_op(req) == REQ_OP_SECURE_ERASE) {

		/* complete ongoing async transfer before issuing secure erase*/

		if (card->host->areq)

		if (mq->qcnt)

			mmc_blk_issue_rw_rq(mq, NULL);

		mmc_blk_issue_secdiscard_rq(mq, req);

	} else if (req && req_op(req) == REQ_OP_FLUSH) {

		/* complete ongoing async transfer before issuing flush */

		if (card->host->areq)

		if (mq->qcnt)

			mmc_blk_issue_rw_rq(mq, NULL);

		mmc_blk_issue_flush(mq, req);

	} else {
@@ -1821,13 +1843,7 @@ void mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) 
	}



out:

	if ((!req && !mq->new_request) || req_is_special)

		/*

		 * Release host when there are no more requests

		 * and after special request(discard, flush) is done.

		 * In case sepecial request, there is no reentry to

		 * the 'mmc_blk_issue_rq' with 'mqrq_prev->req'.

		 */

	if (!mq->qcnt)

		mmc_put_card(card);

}

drivers/mmc/core/queue.c

+47 −28
Original line number Diff line number Diff line
@@ -40,6 +40,35 @@ static int mmc_prep_request(struct request_queue *q, struct request *req) 
	return BLKPREP_OK;

}



struct mmc_queue_req *mmc_queue_req_find(struct mmc_queue *mq,

					 struct request *req)

{

	struct mmc_queue_req *mqrq;

	int i = ffz(mq->qslots);



	if (i >= mq->qdepth)

		return NULL;



	mqrq = &mq->mqrq[i];

	WARN_ON(mqrq->req || mq->qcnt >= mq->qdepth ||

		test_bit(mqrq->task_id, &mq->qslots));

	mqrq->req = req;

	mq->qcnt += 1;

	__set_bit(mqrq->task_id, &mq->qslots);



	return mqrq;

}



void mmc_queue_req_free(struct mmc_queue *mq,

			struct mmc_queue_req *mqrq)

{

	WARN_ON(!mqrq->req || mq->qcnt < 1 ||

		!test_bit(mqrq->task_id, &mq->qslots));

	mqrq->req = NULL;

	mq->qcnt -= 1;

	__clear_bit(mqrq->task_id, &mq->qslots);

}



static int mmc_queue_thread(void *d)

{

	struct mmc_queue *mq = d;
@@ -50,7 +79,7 @@ static int mmc_queue_thread(void *d) 


	down(&mq->thread_sem);

	do {

		struct request *req = NULL;

		struct request *req;



		spin_lock_irq(q->queue_lock);

		set_current_state(TASK_INTERRUPTIBLE);
@@ -63,38 +92,17 @@ static int mmc_queue_thread(void *d) 
			 * Dispatch queue is empty so set flags for

			 * mmc_request_fn() to wake us up.

			 */

			if (mq->mqrq_prev->req)

			if (mq->qcnt)

				cntx->is_waiting_last_req = true;

			else

				mq->asleep = true;

		}

		mq->mqrq_cur->req = req;

		spin_unlock_irq(q->queue_lock);



		if (req || mq->mqrq_prev->req) {

			bool req_is_special = mmc_req_is_special(req);



		if (req || mq->qcnt) {

			set_current_state(TASK_RUNNING);

			mmc_blk_issue_rq(mq, req);

			cond_resched();

			if (mq->new_request) {

				mq->new_request = false;

				continue; /* fetch again */

			}



			/*

			 * Current request becomes previous request

			 * and vice versa.

			 * In case of special requests, current request

			 * has been finished. Do not assign it to previous

			 * request.

			 */

			if (req_is_special)

				mq->mqrq_cur->req = NULL;



			mq->mqrq_prev->brq.mrq.data = NULL;

			mq->mqrq_prev->req = NULL;

			swap(mq->mqrq_prev, mq->mqrq_cur);

		} else {

			if (kthread_should_stop()) {

				set_current_state(TASK_RUNNING);
@@ -177,6 +185,20 @@ static void mmc_queue_setup_discard(struct request_queue *q, 
		queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, q);

}



static struct mmc_queue_req *mmc_queue_alloc_mqrqs(int qdepth)

{

	struct mmc_queue_req *mqrq;

	int i;



	mqrq = kcalloc(qdepth, sizeof(*mqrq), GFP_KERNEL);

	if (mqrq) {

		for (i = 0; i < qdepth; i++)

			mqrq[i].task_id = i;

	}



	return mqrq;

}



#ifdef CONFIG_MMC_BLOCK_BOUNCE

static bool mmc_queue_alloc_bounce_bufs(struct mmc_queue *mq,

					unsigned int bouncesz)
@@ -279,12 +301,9 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, 
		return -ENOMEM;



	mq->qdepth = 2;

	mq->mqrq = kcalloc(mq->qdepth, sizeof(struct mmc_queue_req),

			   GFP_KERNEL);

	mq->mqrq = mmc_queue_alloc_mqrqs(mq->qdepth);

	if (!mq->mqrq)

		goto blk_cleanup;

	mq->mqrq_cur = &mq->mqrq[0];

	mq->mqrq_prev = &mq->mqrq[1];

	mq->queue->queuedata = mq;



	blk_queue_prep_rq(mq->queue, mmc_prep_request);

drivers/mmc/core/queue.h

+7 −3
Original line number Diff line number Diff line
@@ -34,21 +34,21 @@ struct mmc_queue_req { 
	struct scatterlist	*bounce_sg;

	unsigned int		bounce_sg_len;

	struct mmc_async_req	areq;

	int			task_id;

};



struct mmc_queue {

	struct mmc_card		*card;

	struct task_struct	*thread;

	struct semaphore	thread_sem;

	bool			new_request;

	bool			suspended;

	bool			asleep;

	struct mmc_blk_data	*blkdata;

	struct request_queue	*queue;

	struct mmc_queue_req	*mqrq;

	struct mmc_queue_req	*mqrq_cur;

	struct mmc_queue_req	*mqrq_prev;

	int			qdepth;

	int			qcnt;

	unsigned long		qslots;

};



extern int mmc_init_queue(struct mmc_queue *, struct mmc_card *, spinlock_t *,
@@ -64,4 +64,8 @@ extern void mmc_queue_bounce_post(struct mmc_queue_req *); 


extern int mmc_access_rpmb(struct mmc_queue *);



extern struct mmc_queue_req *mmc_queue_req_find(struct mmc_queue *,

						struct request *);

extern void mmc_queue_req_free(struct mmc_queue *, struct mmc_queue_req *);



#endif