From: Christoph Hellwig <hch@infradead.org>
To: Uday Shankar <ushankar@purestorage.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Jens Axboe <axboe@kernel.dk>, Alasdair Kergon <agk@redhat.com>,
Mike Snitzer <snitzer@kernel.org>,
linux-block@vger.kernel.org, dm-devel@redhat.com
Subject: Re: [PATCH] blk-mq: enforce op-specific segment limits in blk_insert_cloned_request
Date: Fri, 17 Feb 2023 08:16:15 -0800 [thread overview]
Message-ID: <Y++oTz0ck9OGE4Se@infradead.org> (raw)
In-Reply-To: <20230216192702.GA801590@dev-ushankar.dev.purestorage.com>
On Thu, Feb 16, 2023 at 12:27:02PM -0700, Uday Shankar wrote:
> * Description:
> * @rq may have been made based on weaker limitations of upper-level queues
> * in request stacking drivers, and it may violate the limitation of @q.
> * Since the block layer and the underlying device driver trust @rq
> * after it is inserted to @q, it should be checked against @q before
> * the insertion using this generic function.
> *
> * Request stacking drivers like request-based dm may change the queue
> * limits when retrying requests on other queues. Those requests need
> * to be checked against the new queue limits again during dispatch.
> */.
>
> Is this concern no longer relevant?
The concern is still valid, but it does not refer to the debug check.
It refers to recalculating nr_phys_segments using
blk_recalc_rq_segments, and the fact that any driver using this
interface needs to stack its limits properly.
next prev parent reply other threads:[~2023-02-17 16:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-15 20:15 [PATCH] blk-mq: enforce op-specific segment limits in blk_insert_cloned_request Uday Shankar
2023-02-16 6:09 ` Christoph Hellwig
2023-02-16 19:27 ` Uday Shankar
2023-02-17 0:13 ` Mike Snitzer
2023-02-17 16:16 ` Christoph Hellwig [this message]
2023-02-17 16:43 ` Mike Snitzer
2023-02-17 21:41 ` Uday Shankar
2023-02-16 13:06 ` [PATCH] " kernel test robot
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=Y++oTz0ck9OGE4Se@infradead.org \
--to=hch@infradead.org \
--cc=agk@redhat.com \
--cc=axboe@kernel.dk \
--cc=dm-devel@redhat.com \
--cc=linux-block@vger.kernel.org \
--cc=snitzer@kernel.org \
--cc=ushankar@purestorage.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).