From: Can Guo <cang@codeaurora.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: "Martin K . Petersen" <martin.petersen@oracle.com>,
"James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
Hannes Reinecke <hare@suse.de>, Ming Lei <ming.lei@redhat.com>,
linux-scsi@vger.kernel.org, linux-block@vger.kernel.org,
Alan Stern <stern@rowland.harvard.edu>,
Stanley Chu <stanley.chu@mediatek.com>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Martin Kepplinger <martin.kepplinger@puri.sm>
Subject: Re: [PATCH v5 8/8] block: Do not accept any requests while suspended
Date: Wed, 09 Dec 2020 14:04:55 +0800 [thread overview]
Message-ID: <142783941949652996dcf510ce203e24@codeaurora.org> (raw)
In-Reply-To: <20201209052951.16136-9-bvanassche@acm.org>
On 2020-12-09 13:29, Bart Van Assche wrote:
> From: Alan Stern <stern@rowland.harvard.edu>
>
> blk_queue_enter() accepts BLK_MQ_REQ_PM requests independent of the
> runtime
> power management state. Now that SCSI domain validation no longer
> depends
> on this behavior, modify the behavior of blk_queue_enter() as follows:
> - Do not accept any requests while suspended.
> - Only process power management requests while suspending or resuming.
>
> Submitting BLK_MQ_REQ_PM requests to a device that is runtime suspended
> causes runtime-suspended devices not to resume as they should. The
> request
> which should cause a runtime resume instead gets issued directly,
> without
> resuming the device first. Of course the device can't handle it
> properly,
> the I/O fails, and the device remains suspended.
>
> The problem is fixed by checking that the queue's runtime-PM status
> isn't RPM_SUSPENDED before allowing a request to be issued, and
> queuing a runtime-resume request if it is. In particular, the inline
> blk_pm_request_resume() routine is renamed blk_pm_resume_queue() and
> the code is unified by merging the surrounding checks into the
> routine. If the queue isn't set up for runtime PM, or there currently
> is no restriction on allowed requests, the request is allowed.
> Likewise if the BLK_MQ_REQ_PM flag is set and the status isn't
> RPM_SUSPENDED. Otherwise a runtime resume is queued and the request
> is blocked until conditions are more suitable.
>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Can Guo <cang@codeaurora.org>
> Cc: Stanley Chu <stanley.chu@mediatek.com>
> Cc: Ming Lei <ming.lei@redhat.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Reported-and-tested-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Reviewed-by: Can Guo <cang@codeaurora.org>
> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> [ bvanassche: modified commit message and removed Cc: stable because
> without
> the previous patches from this series this patch would break parallel
> SCSI
> domain validation + introduced queue_rpm_status() ]
> ---
> block/blk-core.c | 7 ++++---
> block/blk-pm.h | 14 +++++++++-----
> include/linux/blkdev.h | 12 ++++++++++++
> 3 files changed, 25 insertions(+), 8 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index a00bce9f46d8..2d53e2ff48ff 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -18,6 +18,7 @@
> #include <linux/bio.h>
> #include <linux/blkdev.h>
> #include <linux/blk-mq.h>
> +#include <linux/blk-pm.h>
> #include <linux/highmem.h>
> #include <linux/mm.h>
> #include <linux/pagemap.h>
> @@ -440,7 +441,8 @@ int blk_queue_enter(struct request_queue *q,
> blk_mq_req_flags_t flags)
> * responsible for ensuring that that counter is
> * globally visible before the queue is unfrozen.
> */
> - if (pm || !blk_queue_pm_only(q)) {
> + if ((pm && queue_rpm_status(q) != RPM_SUSPENDED) ||
> + !blk_queue_pm_only(q)) {
> success = true;
> } else {
> percpu_ref_put(&q->q_usage_counter);
> @@ -465,8 +467,7 @@ int blk_queue_enter(struct request_queue *q,
> blk_mq_req_flags_t flags)
>
> wait_event(q->mq_freeze_wq,
> (!q->mq_freeze_depth &&
> - (pm || (blk_pm_request_resume(q),
> - !blk_queue_pm_only(q)))) ||
> + blk_pm_resume_queue(pm, q)) ||
> blk_queue_dying(q));
> if (blk_queue_dying(q))
> return -ENODEV;
> diff --git a/block/blk-pm.h b/block/blk-pm.h
> index ea5507d23e75..a2283cc9f716 100644
> --- a/block/blk-pm.h
> +++ b/block/blk-pm.h
> @@ -6,11 +6,14 @@
> #include <linux/pm_runtime.h>
>
> #ifdef CONFIG_PM
> -static inline void blk_pm_request_resume(struct request_queue *q)
> +static inline int blk_pm_resume_queue(const bool pm, struct
> request_queue *q)
> {
> - if (q->dev && (q->rpm_status == RPM_SUSPENDED ||
> - q->rpm_status == RPM_SUSPENDING))
> - pm_request_resume(q->dev);
> + if (!q->dev || !blk_queue_pm_only(q))
> + return 1; /* Nothing to do */
> + if (pm && q->rpm_status != RPM_SUSPENDED)
> + return 1; /* Request allowed */
> + pm_request_resume(q->dev);
> + return 0;
> }
>
> static inline void blk_pm_mark_last_busy(struct request *rq)
> @@ -44,8 +47,9 @@ static inline void blk_pm_put_request(struct request
> *rq)
> --rq->q->nr_pending;
> }
> #else
> -static inline void blk_pm_request_resume(struct request_queue *q)
> +static inline int blk_pm_resume_queue(const bool pm, struct
> request_queue *q)
> {
> + return 1;
> }
>
> static inline void blk_pm_mark_last_busy(struct request *rq)
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 7d4b746f7e6a..2b6fc3fb3a99 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -692,6 +692,18 @@ static inline bool queue_is_mq(struct
> request_queue *q)
> return q->mq_ops;
> }
>
> +#ifdef CONFIG_PM
> +static inline enum rpm_status queue_rpm_status(struct request_queue
> *q)
> +{
> + return q->rpm_status;
> +}
> +#else
> +static inline enum rpm_status queue_rpm_status(struct request_queue
> *q)
> +{
> + return RPM_ACTIVE;
> +}
> +#endif
> +
> static inline enum blk_zoned_model
> blk_queue_zoned_model(struct request_queue *q)
> {
next prev parent reply other threads:[~2020-12-09 6:06 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 5:29 [PATCH v5 0/8] Rework runtime suspend and SPI domain validation Bart Van Assche
2020-12-09 5:29 ` [PATCH v5 1/8] block: Fix a race in the runtime power management code Bart Van Assche
2020-12-09 5:29 ` [PATCH v5 2/8] block: Introduce BLK_MQ_REQ_PM Bart Van Assche
2020-12-09 6:06 ` Can Guo
2020-12-09 5:29 ` [PATCH v5 3/8] ide: Do not set the RQF_PREEMPT flag for sense requests Bart Van Assche
2020-12-09 5:29 ` [PATCH v5 4/8] ide: Mark power management requests with RQF_PM instead of RQF_PREEMPT Bart Van Assche
2020-12-09 5:29 ` [PATCH v5 5/8] scsi_transport_spi: Set RQF_PM for domain validation commands Bart Van Assche
2020-12-09 7:34 ` Hannes Reinecke
2020-12-09 5:29 ` [PATCH v5 6/8] scsi: Only process PM requests if rpm_status != RPM_ACTIVE Bart Van Assche
2020-12-09 6:06 ` Can Guo
2020-12-09 5:29 ` [PATCH v5 7/8] block: Remove RQF_PREEMPT and BLK_MQ_REQ_PREEMPT Bart Van Assche
2020-12-09 6:05 ` Can Guo
2020-12-09 5:29 ` [PATCH v5 8/8] block: Do not accept any requests while suspended Bart Van Assche
2020-12-09 6:04 ` Can Guo [this message]
2020-12-09 7:36 ` Hannes Reinecke
2020-12-09 16:44 ` [PATCH v5 0/8] Rework runtime suspend and SPI domain validation Martin K. Petersen
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