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Date: Wed, 3 Apr 2024 13:06:17 -0400
From: Mike Snitzer <snitzer@kernel.org>
To: Julia Lawall <julia.lawall@inria.fr>
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)
Message-ID: <Zg2MiSlrQ9zTna6q@redhat.com>
References: <801d737e-f7c0-b853-d7e-63eb68c7fd7b@inria.fr>
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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.

Thanks,
Mike