Received-SPF: pass (google.com: domain of linux-kernel+bounces-130253-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Date: Wed, 3 Apr 2024 13:09:00 -0400 (EDT)
From: Julia Lawall <julia.lawall@inria.fr>
To: Mike Snitzer <snitzer@kernel.org>
cc: Matthew Sakai <msakai@redhat.com>, linux-kernel@vger.kernel.org, 
    oe-kbuild-all@lists.linux.dev, dm-devel@list.linux.dev
Subject: Re: drivers/md/dm-vdo/data-vio.c:969:2-8: preceding lock on line
 966 (fwd)
In-Reply-To: <Zg2MiSlrQ9zTna6q@redhat.com>
Message-ID: <677fa1fd-6f16-438e-2b95-8e81cabf4bf0@inria.fr>
References: <801d737e-f7c0-b853-d7e-63eb68c7fd7b@inria.fr> <Zg2MiSlrQ9zTna6q@redhat.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII


On Wed, 3 Apr 2024, Mike Snitzer wrote:

> On Wed, Apr 03 2024 at 12:47P -0400,
> Julia Lawall <julia.lawall@inria.fr> wrote:
>
> > Hello,
> >
> > Please check whether the lock should be released before the returns.
> >
> > julia
> >
> > ---------- Forwarded message ----------
> > Date: Wed, 3 Apr 2024 22:16:44 +0800
> > From: kernel test robot <lkp@intel.com>
> > To: oe-kbuild@lists.linux.dev
> > Cc: lkp@intel.com, Julia Lawall <julia.lawall@inria.fr>
> > Subject: drivers/md/dm-vdo/data-vio.c:969:2-8: preceding lock on line 966
> >
> > BCC: lkp@intel.com
> > CC: oe-kbuild-all@lists.linux.dev
> > CC: linux-kernel@vger.kernel.org
> > TO: Mike Snitzer <snitzer@kernel.org>
> > CC: Matthew Sakai <msakai@redhat.com>
> >
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   3e92c1e6cd876754b64d1998ec0a01800ed954a6
> > commit: f36b1d3ba533d21b5b793623f05761b0297d114e dm vdo: use a proper Makefile for dm-vdo
> > date:   6 weeks ago
> > :::::: branch date: 11 hours ago
> > :::::: commit date: 6 weeks ago
> > config: s390-randconfig-r052-20240403 (https://download.01.org/0day-ci/archive/20240403/202404032212.NV7EJ2Zj-lkp@intel.com/config)
> > compiler: s390-linux-gcc (GCC) 13.2.0
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Reported-by: Julia Lawall <julia.lawall@inria.fr>
> > | Closes: https://lore.kernel.org/r/202404032212.NV7EJ2Zj-lkp@intel.com/
> >
> > cocci warnings: (new ones prefixed by >>)
> > >> drivers/md/dm-vdo/data-vio.c:969:2-8: preceding lock on line 966
> >    drivers/md/dm-vdo/data-vio.c:972:2-8: preceding lock on line 966
> >
> > vim +969 drivers/md/dm-vdo/data-vio.c
> >
> > 79535a7881c0cb Matthew Sakai 2023-11-16  952
> > 79535a7881c0cb Matthew Sakai 2023-11-16  953  /**
> > 79535a7881c0cb Matthew Sakai 2023-11-16  954   * vdo_launch_bio() - Acquire a data_vio from the pool, assign the bio to it, and launch it.
> > 79535a7881c0cb Matthew Sakai 2023-11-16  955   *
> > 79535a7881c0cb Matthew Sakai 2023-11-16  956   * This will block if data_vios or discard permits are not available.
> > 79535a7881c0cb Matthew Sakai 2023-11-16  957   */
> > 79535a7881c0cb Matthew Sakai 2023-11-16  958  void vdo_launch_bio(struct data_vio_pool *pool, struct bio *bio)
> > 79535a7881c0cb Matthew Sakai 2023-11-16  959  {
> > 79535a7881c0cb Matthew Sakai 2023-11-16  960  	struct data_vio *data_vio;
> > 79535a7881c0cb Matthew Sakai 2023-11-16  961
> > 79535a7881c0cb Matthew Sakai 2023-11-16  962  	ASSERT_LOG_ONLY(!vdo_is_state_quiescent(&pool->state),
> > 79535a7881c0cb Matthew Sakai 2023-11-16  963  			"data_vio_pool not quiescent on acquire");
> > 79535a7881c0cb Matthew Sakai 2023-11-16  964
> > 79535a7881c0cb Matthew Sakai 2023-11-16  965  	bio->bi_private = (void *) jiffies;
> > 79535a7881c0cb Matthew Sakai 2023-11-16 @966  	spin_lock(&pool->lock);
> > 79535a7881c0cb Matthew Sakai 2023-11-16  967  	if ((bio_op(bio) == REQ_OP_DISCARD) &&
> > 79535a7881c0cb Matthew Sakai 2023-11-16  968  	    !acquire_permit(&pool->discard_limiter, bio))
> > 79535a7881c0cb Matthew Sakai 2023-11-16 @969  		return;
> > 79535a7881c0cb Matthew Sakai 2023-11-16  970
> > 79535a7881c0cb Matthew Sakai 2023-11-16  971  	if (!acquire_permit(&pool->limiter, bio))
> > 79535a7881c0cb Matthew Sakai 2023-11-16  972  		return;
> > 79535a7881c0cb Matthew Sakai 2023-11-16  973
> > 79535a7881c0cb Matthew Sakai 2023-11-16  974  	data_vio = get_available_data_vio(pool);
> > 79535a7881c0cb Matthew Sakai 2023-11-16  975  	spin_unlock(&pool->lock);
> > 79535a7881c0cb Matthew Sakai 2023-11-16  976  	launch_bio(pool->completion.vdo, data_vio, bio);
> > 79535a7881c0cb Matthew Sakai 2023-11-16  977  }
> > 79535a7881c0cb Matthew Sakai 2023-11-16  978
> >
> > :::::: The code at line 969 was first introduced by commit
> > :::::: 79535a7881c0cbe95063a2670d840cc950ae9282 dm vdo: add data_vio, the request object which services incoming bios
> >
> > :::::: TO: Matthew Sakai <msakai@redhat.com>
> > :::::: CC: Mike Snitzer <snitzer@kernel.org>
> >
> > --
> > 0-DAY CI Kernel Test Service
> > https://github.com/intel/lkp-tests/wiki
> >
>
> Thanks for the report but this is reacting to older code. Changes were
> made to address sparse's concerns about this same code, please see:
> commit 872564c501b7 ("dm vdo data-vio: silence sparse warnings about
> locking context imbalance").
>
> If wait_permit()'s sparse __releases annotation is somehow
> insufficient for silencing cocci please let me know.

I don't think the Coccinelle rule checks the annotation.  But the warning
should not be negerated again.

thanks,
julia