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

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On 16 November 2018 at 09:10, Christoph Hellwig <hch@xxxxxx> 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@xxxxxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>

Looks good, thanks!

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

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
>



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