From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mike Snitzer <snitzer@redhat.com>
Subject: Re: [PATCH v2 2/3] block: make blk_crypto_rq_bio_prep() able to fail
Date: Wed, 23 Sep 2020 20:57:18 -0400
Message-ID: <20200924005717.GC10500@redhat.com>
References: <20200916035315.34046-1-ebiggers@kernel.org>
 <20200916035315.34046-3-ebiggers@kernel.org>
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To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-block@vger.kernel.org, Jens Axboe <axboe@kernel.dk>, Miaohe Lin <linmiaohe@huawei.com>, dm-devel@redhat.com, Satya Tangirala <satyat@google.com>
List-Id: dm-devel.ids

On Tue, Sep 15 2020 at 11:53pm -0400,
Eric Biggers <ebiggers@kernel.org> wrote:

> From: Eric Biggers <ebiggers@google.com>
> 
> blk_crypto_rq_bio_prep() assumes its gfp_mask argument always includes
> __GFP_DIRECT_RECLAIM, so that the mempool_alloc() will always succeed.
> 
> However, blk_crypto_rq_bio_prep() might be called with GFP_ATOMIC via
> setup_clone() in drivers/md/dm-rq.c.
> 
> This case isn't currently reachable with a bio that actually has an
> encryption context.  However, it's fragile to rely on this.  Just make
> blk_crypto_rq_bio_prep() able to fail.
> 
> Cc: Miaohe Lin <linmiaohe@huawei.com>
> Suggested-by: Satya Tangirala <satyat@google.com>
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Reviewed-by: Mike Snitzer <snitzer@redhat.com>