[dm-devel] [PATCH v2 2/3] block: make blk_crypto_rq_bio_prep() able to fail

[Mike Snitzer]

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

> From: Eric Biggers <ebiggers at 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 at huawei.com>
> Suggested-by: Satya Tangirala <satyat at google.com>
> Signed-off-by: Eric Biggers <ebiggers at google.com>

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