From: Bart Van Assche <bvanassche@acm.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, Keith Busch <keith.busch@intel.com>,
Sagi Grimberg <sagi@grimberg.me>,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
Max Gurtovoy <maxg@mellanox.com>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 3/5] nvme: don't abort completed request in nvme_cancel_request
Date: Tue, 23 Jul 2019 12:22:46 -0700 [thread overview]
Message-ID: <7e484af3-15d5-06fd-5c7b-2fbe38e5b8f1@acm.org> (raw)
In-Reply-To: <20190723010845.GD30776@ming.t460p>
On 7/22/19 6:08 PM, Ming Lei wrote:
> On Mon, Jul 22, 2019 at 08:27:32AM -0700, Bart Van Assche wrote:
>> On 7/21/19 10:39 PM, Ming Lei wrote:
>>> Before aborting in-flight requests, all IO queues have been shutdown.
>>> However, request's completion fn may not be done yet because it may
>>> be scheduled to run via IPI.
>>>
>>> So don't abort one request if it is marked as completed, otherwise
>>> we may abort one normal completed request.
>>>
>>> Cc: Max Gurtovoy <maxg@mellanox.com>
>>> Cc: Sagi Grimberg <sagi@grimberg.me>
>>> Cc: Keith Busch <keith.busch@intel.com>
>>> Cc: Christoph Hellwig <hch@lst.de>
>>> Signed-off-by: Ming Lei <ming.lei@redhat.com>
>>> ---
>>> drivers/nvme/host/core.c | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>>> index cc09b81fc7f4..cb8007cce4d1 100644
>>> --- a/drivers/nvme/host/core.c
>>> +++ b/drivers/nvme/host/core.c
>>> @@ -285,6 +285,10 @@ EXPORT_SYMBOL_GPL(nvme_complete_rq);
>>> bool nvme_cancel_request(struct request *req, void *data, bool reserved)
>>> {
>>> + /* don't abort one completed request */
>>> + if (blk_mq_request_completed(req))
>>> + return;
>>> +
>>> dev_dbg_ratelimited(((struct nvme_ctrl *) data)->device,
>>> "Cancelling I/O %d", req->tag);
>>
>> Something I probably already asked before: what prevents that
>> nvme_cancel_request() is executed concurrently with the completion handler
>> of the same request?
>
> The commit log did mention the point:
>
> Before aborting in-flight requests, all IO queues have been shutdown.
>
> which implies that no concurrent normal completion.
How about adding that explanation as a comment above
nvme_cancel_request()? That would make that explanation much easier to
find compared to having to search through commit logs.
Thanks,
Bart.
WARNING: multiple messages have this Message-ID (diff)
From: bvanassche@acm.org (Bart Van Assche)
Subject: [PATCH 3/5] nvme: don't abort completed request in nvme_cancel_request
Date: Tue, 23 Jul 2019 12:22:46 -0700 [thread overview]
Message-ID: <7e484af3-15d5-06fd-5c7b-2fbe38e5b8f1@acm.org> (raw)
In-Reply-To: <20190723010845.GD30776@ming.t460p>
On 7/22/19 6:08 PM, Ming Lei wrote:
> On Mon, Jul 22, 2019@08:27:32AM -0700, Bart Van Assche wrote:
>> On 7/21/19 10:39 PM, Ming Lei wrote:
>>> Before aborting in-flight requests, all IO queues have been shutdown.
>>> However, request's completion fn may not be done yet because it may
>>> be scheduled to run via IPI.
>>>
>>> So don't abort one request if it is marked as completed, otherwise
>>> we may abort one normal completed request.
>>>
>>> Cc: Max Gurtovoy <maxg at mellanox.com>
>>> Cc: Sagi Grimberg <sagi at grimberg.me>
>>> Cc: Keith Busch <keith.busch at intel.com>
>>> Cc: Christoph Hellwig <hch at lst.de>
>>> Signed-off-by: Ming Lei <ming.lei at redhat.com>
>>> ---
>>> drivers/nvme/host/core.c | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>>> index cc09b81fc7f4..cb8007cce4d1 100644
>>> --- a/drivers/nvme/host/core.c
>>> +++ b/drivers/nvme/host/core.c
>>> @@ -285,6 +285,10 @@ EXPORT_SYMBOL_GPL(nvme_complete_rq);
>>> bool nvme_cancel_request(struct request *req, void *data, bool reserved)
>>> {
>>> + /* don't abort one completed request */
>>> + if (blk_mq_request_completed(req))
>>> + return;
>>> +
>>> dev_dbg_ratelimited(((struct nvme_ctrl *) data)->device,
>>> "Cancelling I/O %d", req->tag);
>>
>> Something I probably already asked before: what prevents that
>> nvme_cancel_request() is executed concurrently with the completion handler
>> of the same request?
>
> The commit log did mention the point:
>
> Before aborting in-flight requests, all IO queues have been shutdown.
>
> which implies that no concurrent normal completion.
How about adding that explanation as a comment above
nvme_cancel_request()? That would make that explanation much easier to
find compared to having to search through commit logs.
Thanks,
Bart.
next prev parent reply other threads:[~2019-07-23 19:22 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 5:39 [PATCH 0/5] blk-mq: wait until completed req's complete fn is run Ming Lei
2019-07-22 5:39 ` Ming Lei
2019-07-22 5:39 ` [PATCH 1/5] blk-mq: introduce blk_mq_request_completed() Ming Lei
2019-07-22 5:39 ` Ming Lei
2019-07-23 20:26 ` Sagi Grimberg
2019-07-23 20:26 ` Sagi Grimberg
2019-07-22 5:39 ` [PATCH 2/5] blk-mq: introduce blk_mq_tagset_wait_completed_request() Ming Lei
2019-07-22 5:39 ` Ming Lei
2019-07-22 15:25 ` Bart Van Assche
2019-07-22 15:25 ` Bart Van Assche
2019-07-23 1:06 ` Ming Lei
2019-07-23 1:06 ` Ming Lei
2019-07-23 20:54 ` Bart Van Assche
2019-07-23 20:54 ` Bart Van Assche
2019-07-24 1:34 ` Ming Lei
2019-07-24 1:34 ` Ming Lei
2019-07-23 20:27 ` Sagi Grimberg
2019-07-23 20:27 ` Sagi Grimberg
2019-07-22 5:39 ` [PATCH 3/5] nvme: don't abort completed request in nvme_cancel_request Ming Lei
2019-07-22 5:39 ` Ming Lei
2019-07-22 15:27 ` Bart Van Assche
2019-07-22 15:27 ` Bart Van Assche
2019-07-22 23:22 ` Keith Busch
2019-07-22 23:22 ` Keith Busch
2019-07-23 0:07 ` Sagi Grimberg
2019-07-23 0:07 ` Sagi Grimberg
2019-07-23 1:08 ` Ming Lei
2019-07-23 1:08 ` Ming Lei
2019-07-23 19:22 ` Bart Van Assche [this message]
2019-07-23 19:22 ` Bart Van Assche
2019-07-23 20:27 ` Sagi Grimberg
2019-07-23 20:27 ` Sagi Grimberg
2019-07-22 5:39 ` [PATCH 4/5] nvme: wait until all completed request's complete fn is called Ming Lei
2019-07-22 5:39 ` Ming Lei
2019-07-23 16:14 ` Dongli Zhang
2019-07-23 16:14 ` Dongli Zhang
2019-07-24 2:05 ` Ming Lei
2019-07-24 2:05 ` Ming Lei
2019-07-23 20:29 ` Sagi Grimberg
2019-07-23 20:29 ` Sagi Grimberg
2019-07-24 1:43 ` Ming Lei
2019-07-24 1:43 ` Ming Lei
2019-07-22 5:39 ` [PATCH 5/5] blk-mq: remove blk_mq_complete_request_sync Ming Lei
2019-07-22 5:39 ` Ming Lei
2019-07-23 20:30 ` Sagi Grimberg
2019-07-23 20:30 ` Sagi Grimberg
2019-07-22 23:27 ` [PATCH 0/5] blk-mq: wait until completed req's complete fn is run Bob Liu
2019-07-22 23:27 ` Bob Liu
2019-07-23 1:10 ` Ming Lei
2019-07-23 1:10 ` Ming Lei
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7e484af3-15d5-06fd-5c7b-2fbe38e5b8f1@acm.org \
--to=bvanassche@acm.org \
--cc=axboe@kernel.dk \
--cc=hch@lst.de \
--cc=keith.busch@intel.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-nvme@lists.infradead.org \
--cc=maxg@mellanox.com \
--cc=ming.lei@redhat.com \
--cc=sagi@grimberg.me \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.