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From: Luis Chamberlain <mcgrof@kernel.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@redhat.com>, Jan Kara <jack@suse.cz>,
	Ming Lei <ming.lei@redhat.com>, Nicolai Stange <nstange@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.com>, yu kuai <yukuai3@huawei.com>,
	linux-block@vger.kernel.org,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Omar Sandoval <osandov@fb.com>, Hannes Reinecke <hare@suse.com>,
	Michal Hocko <mhocko@kernel.org>
Subject: Re: [RFC v2 5/5] block: revert back to synchronous request_queue removal
Date: Tue, 14 Apr 2020 03:38:04 +0000	[thread overview]
Message-ID: <20200414033804.GO11244@42.do-not-panic.com> (raw)
In-Reply-To: <64c9212d-aaa3-d172-0ab9-0fc0e25a019a@acm.org>

On Sat, Apr 11, 2020 at 04:21:17PM -0700, Bart Van Assche wrote:
> On 2020-04-10 14:27, Luis Chamberlain wrote:
> > On Fri, Apr 10, 2020 at 2:50 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
> >>
> >> On Fri, Apr 10, 2020 at 8:34 AM Luis Chamberlain <mcgrof@kernel.org> wrote:
> >>> On Thu, Apr 09, 2020 at 08:12:21PM -0700, Bart Van Assche wrote:
> >>>> Please add a might_sleep() call in blk_put_queue() since with this patch
> >>>> applied it is no longer allowed to call blk_put_queue() from atomic context.
> >>>
> >>> Sure thing.
> >>
> >> On second though, I don't think blk_put_queue() would be the right
> >> place for might_sleep(), given we really only care about the *last*
> >> refcount decrement to 0. So I'll move it to blk_release_queue().
> >> Granted, at that point we are too late, and we'd get a splat about
> >> this issue *iff* we really sleep. So yeah, I do suppose that forcing
> >> this check there still makes sense.
> > 
> > I'll add might_sleep() to both blk_release_queue() *and* blk_cleanup_queue().
> 
> Since there is already an unconditional mutex_lock() call in
> blk_cleanup_queue(), do we really need to add a might_sleep() call in
> blk_cleanup_queue()?

You are right, mutex_lock() already has a might_sleep() sprinkled on it.

  Luis


      reply	other threads:[~2020-04-14  3:38 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-09 21:45 [RFC v2 0/5] blktrace: fix use after free Luis Chamberlain
2020-04-09 21:45 ` [RFC v2 1/5] block: move main block debugfs initialization to its own file Luis Chamberlain
2020-04-10  2:48   ` Bart Van Assche
2020-04-09 21:45 ` [RFC v2 2/5] blktrace: fix debugfs use after free Luis Chamberlain
2020-04-10  2:52   ` Bart Van Assche
2020-04-10 19:58     ` Luis Chamberlain
2020-04-11 23:09       ` Bart Van Assche
2020-04-14  3:32         ` Luis Chamberlain
2020-04-09 21:45 ` [RFC v2 3/5] blktrace: ref count the request_queue during ioctl Luis Chamberlain
2020-04-10  2:58   ` Bart Van Assche
2020-04-09 21:45 ` [RFC v2 4/5] mm/swapfile: refcount block and queue before using blkcg_schedule_throttle() Luis Chamberlain
2020-04-10  3:02   ` Bart Van Assche
2020-04-10 14:34     ` Luis Chamberlain
2020-04-09 21:45 ` [RFC v2 5/5] block: revert back to synchronous request_queue removal Luis Chamberlain
2020-04-10  3:12   ` Bart Van Assche
2020-04-10 14:34     ` Luis Chamberlain
2020-04-10 20:50       ` Luis Chamberlain
2020-04-10 21:27         ` Luis Chamberlain
2020-04-11 23:21           ` Bart Van Assche
2020-04-14  3:38             ` Luis Chamberlain [this message]

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