[dm-devel] [PATCH v2 1/3] block: make bio_crypt_clone() 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>
> 
> bio_crypt_clone() assumes its gfp_mask argument always includes
> __GFP_DIRECT_RECLAIM, so that the mempool_alloc() will always succeed.
> 
> However, bio_crypt_clone() might be called with GFP_ATOMIC via
> setup_clone() in drivers/md/dm-rq.c, or with GFP_NOWAIT via
> kcryptd_io_read() in drivers/md/dm-crypt.c.
> 
> Neither case is currently reachable with a bio that actually has an
> encryption context.  However, it's fragile to rely on this.  Just make
> bio_crypt_clone() able to fail, analogous to bio_integrity_clone().
> 
> Reported-by: Miaohe Lin <linmiaohe at huawei.com>
> Cc: Satya Tangirala <satyat at google.com>
> Signed-off-by: Eric Biggers <ebiggers at google.com>

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