Re: [PATCH 6/6] mmc: stop abusing the request queue_lock pointer

Ulf Hansson
2018-11-17T10:13:00Z

On 16 November 2018 at 09:10, Christoph Hellwig <hch@lst.de> wrote:
> Replace the lock in mmc_blk_data that is only used through a pointer
> in struct mmc_queue and to protect fields in that structure with
> an actual lock in struct mmc_queue.
>
> Suggested-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good, thanks!

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

Kind regards
Uffe

> ---
> drivers/mmc/core/block.c | 24 +++++++++++-------------
> drivers/mmc/core/queue.c | 31 +++++++++++++++----------------
> drivers/mmc/core/queue.h | 4 ++--
> 3 files changed, 28 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index 70ec465beb69..2c329a3e3fdb 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -100,7 +100,6 @@ static DEFINE_IDA(mmc_rpmb_ida);
> * There is one mmc_blk_data per slot.
> */
> struct mmc_blk_data {
> - spinlock_t lock;
> struct device *parent;
> struct gendisk *disk;
> struct mmc_queue queue;
> @@ -1483,7 +1482,7 @@ static void mmc_blk_cqe_complete_rq(struct mmc_queue *mq, struct request *req)
> blk_mq_end_request(req, BLK_STS_OK);
> }
>
> - spin_lock_irqsave(mq->lock, flags);
> + spin_lock_irqsave(&mq->lock, flags);
>
> mq->in_flight[mmc_issue_type(mq, req)] -= 1;
>
> @@ -1491,7 +1490,7 @@ static void mmc_blk_cqe_complete_rq(struct mmc_queue *mq, struct request *req)
>
> mmc_cqe_check_busy(mq);
>
> - spin_unlock_irqrestore(mq->lock, flags);
> + spin_unlock_irqrestore(&mq->lock, flags);
>
> if (!mq->cqe_busy)
> blk_mq_run_hw_queues(q, true);
> @@ -1991,13 +1990,13 @@ static void mmc_blk_mq_dec_in_flight(struct mmc_queue *mq, struct request *req)
> unsigned long flags;
> bool put_card;
>
> - spin_lock_irqsave(mq->lock, flags);
> + spin_lock_irqsave(&mq->lock, flags);
>
> mq->in_flight[mmc_issue_type(mq, req)] -= 1;
>
> put_card = (mmc_tot_in_flight(mq) == 0);
>
> - spin_unlock_irqrestore(mq->lock, flags);
> + spin_unlock_irqrestore(&mq->lock, flags);
>
> if (put_card)
> mmc_put_card(mq->card, &mq->ctx);
> @@ -2093,11 +2092,11 @@ static void mmc_blk_mq_req_done(struct mmc_request *mrq)
> * request does not need to wait (although it does need to
> * complete complete_req first).
> */
> - spin_lock_irqsave(mq->lock, flags);
> + spin_lock_irqsave(&mq->lock, flags);
> mq->complete_req = req;
> mq->rw_wait = false;
> waiting = mq->waiting;
> - spin_unlock_irqrestore(mq->lock, flags);
> + spin_unlock_irqrestore(&mq->lock, flags);
>
> /*
> * If 'waiting' then the waiting task will complete this
> @@ -2116,10 +2115,10 @@ static void mmc_blk_mq_req_done(struct mmc_request *mrq)
> /* Take the recovery path for errors or urgent background operations */
> if (mmc_blk_rq_error(&mqrq->brq) ||
> mmc_blk_urgent_bkops_needed(mq, mqrq)) {
> - spin_lock_irqsave(mq->lock, flags);
> + spin_lock_irqsave(&mq->lock, flags);
> mq->recovery_needed = true;
> mq->recovery_req = req;
> - spin_unlock_irqrestore(mq->lock, flags);
> + spin_unlock_irqrestore(&mq->lock, flags);
> wake_up(&mq->wait);
> schedule_work(&mq->recovery_work);
> return;
> @@ -2142,7 +2141,7 @@ static bool mmc_blk_rw_wait_cond(struct mmc_queue *mq, int *err)
> * Wait while there is another request in progress, but not if recovery
> * is needed. Also indicate whether there is a request waiting to start.
> */
> - spin_lock_irqsave(mq->lock, flags);
> + spin_lock_irqsave(&mq->lock, flags);
> if (mq->recovery_needed) {
> *err = -EBUSY;
> done = true;
> @@ -2150,7 +2149,7 @@ static bool mmc_blk_rw_wait_cond(struct mmc_queue *mq, int *err)
> done = !mq->rw_wait;
> }
> mq->waiting = !done;
> - spin_unlock_irqrestore(mq->lock, flags);
> + spin_unlock_irqrestore(&mq->lock, flags);
>
> return done;
> }
> @@ -2327,12 +2326,11 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
> goto err_kfree;
> }
>
> - spin_lock_init(&md->lock);
> INIT_LIST_HEAD(&md->part);
> INIT_LIST_HEAD(&md->rpmbs);
> md->usage = 1;
>
> - ret = mmc_init_queue(&md->queue, card, &md->lock);
> + ret = mmc_init_queue(&md->queue, card);
> if (ret)
> goto err_putdisk;
>
> diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
> index 4485cf12218c..35cc138b096d 100644
> --- a/drivers/mmc/core/queue.c
> +++ b/drivers/mmc/core/queue.c
> @@ -89,9 +89,9 @@ void mmc_cqe_recovery_notifier(struct mmc_request *mrq)
> struct mmc_queue *mq = q->queuedata;
> unsigned long flags;
>
> - spin_lock_irqsave(mq->lock, flags);
> + spin_lock_irqsave(&mq->lock, flags);
> __mmc_cqe_recovery_notifier(mq);
> - spin_unlock_irqrestore(mq->lock, flags);
> + spin_unlock_irqrestore(&mq->lock, flags);
> }
>
> static enum blk_eh_timer_return mmc_cqe_timed_out(struct request *req)
> @@ -128,14 +128,14 @@ static enum blk_eh_timer_return mmc_mq_timed_out(struct request *req,
> unsigned long flags;
> int ret;
>
> - spin_lock_irqsave(mq->lock, flags);
> + spin_lock_irqsave(&mq->lock, flags);
>
> if (mq->recovery_needed || !mq->use_cqe)
> ret = BLK_EH_RESET_TIMER;
> else
> ret = mmc_cqe_timed_out(req);
>
> - spin_unlock_irqrestore(mq->lock, flags);
> + spin_unlock_irqrestore(&mq->lock, flags);
>
> return ret;
> }
> @@ -157,9 +157,9 @@ static void mmc_mq_recovery_handler(struct work_struct *work)
>
> mq->in_recovery = false;
>
> - spin_lock_irq(mq->lock);
> + spin_lock_irq(&mq->lock);
> mq->recovery_needed = false;
> - spin_unlock_irq(mq->lock);
> + spin_unlock_irq(&mq->lock);
>
> mmc_put_card(mq->card, &mq->ctx);
>
> @@ -258,10 +258,10 @@ static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
>
> issue_type = mmc_issue_type(mq, req);
>
> - spin_lock_irq(mq->lock);
> + spin_lock_irq(&mq->lock);
>
> if (mq->recovery_needed || mq->busy) {
> - spin_unlock_irq(mq->lock);
> + spin_unlock_irq(&mq->lock);
> return BLK_STS_RESOURCE;
> }
>
> @@ -269,7 +269,7 @@ static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
> case MMC_ISSUE_DCMD:
> if (mmc_cqe_dcmd_busy(mq)) {
> mq->cqe_busy |= MMC_CQE_DCMD_BUSY;
> - spin_unlock_irq(mq->lock);
> + spin_unlock_irq(&mq->lock);
> return BLK_STS_RESOURCE;
> }
> break;
> @@ -294,7 +294,7 @@ static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
> get_card = (mmc_tot_in_flight(mq) == 1);
> cqe_retune_ok = (mmc_cqe_qcnt(mq) == 1);
>
> - spin_unlock_irq(mq->lock);
> + spin_unlock_irq(&mq->lock);
>
> if (!(req->rq_flags & RQF_DONTPREP)) {
> req_to_mmc_queue_req(req)->retries = 0;
> @@ -328,12 +328,12 @@ static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
> if (issued != MMC_REQ_STARTED) {
> bool put_card = false;
>
> - spin_lock_irq(mq->lock);
> + spin_lock_irq(&mq->lock);
> mq->in_flight[issue_type] -= 1;
> if (mmc_tot_in_flight(mq) == 0)
> put_card = true;
> mq->busy = false;
> - spin_unlock_irq(mq->lock);
> + spin_unlock_irq(&mq->lock);
> if (put_card)
> mmc_put_card(card, &mq->ctx);
> } else {
> @@ -385,19 +385,18 @@ static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card)
> * mmc_init_queue - initialise a queue structure.
> * @mq: mmc queue
> * @card: mmc card to attach this queue
> - * @lock: queue lock
> *
> * Initialise a MMC card request queue.
> */
> -int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
> - spinlock_t *lock)
> +int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card)
> {
> struct mmc_host *host = card->host;
> int ret;
>
> mq->card = card;
> - mq->lock = lock;
> mq->use_cqe = host->cqe_enabled;
> +
> + spin_lock_init(&mq->lock);
>
> memset(&mq->tag_set, 0, sizeof(mq->tag_set));
> mq->tag_set.ops = &mmc_mq_ops;
> diff --git a/drivers/mmc/core/queue.h b/drivers/mmc/core/queue.h
> index 5421f1542e71..fd11491ced9f 100644
> --- a/drivers/mmc/core/queue.h
> +++ b/drivers/mmc/core/queue.h
> @@ -73,11 +73,11 @@ struct mmc_queue_req {
>
> struct mmc_queue {
> struct mmc_card *card;
> - spinlock_t *lock;
> struct mmc_ctx ctx;
> struct blk_mq_tag_set tag_set;
> struct mmc_blk_data *blkdata;
> struct request_queue *queue;
> + spinlock_t lock;
> int in_flight[MMC_ISSUE_MAX];
> unsigned int cqe_busy;
> #define MMC_CQE_DCMD_BUSY BIT(0)
> @@ -96,7 +96,7 @@ struct mmc_queue {
> struct work_struct complete_work;
> };
>
> -extern int mmc_init_queue(struct mmc_queue *, struct mmc_card *, spinlock_t *);
> +extern int mmc_init_queue(struct mmc_queue *, struct mmc_card *);
> extern void mmc_cleanup_queue(struct mmc_queue *);
> extern void mmc_queue_suspend(struct mmc_queue *);
> extern void mmc_queue_resume(struct mmc_queue *);
> --
> 2.19.1
>