Re: [PATCH] block: bio: ensure newly added bio flags don't override BVEC_POOL_IDX

[Hannes Reinecke <hare@suse.de>]

On 4/3/19 11:15 AM, Johannes Thumshirn wrote:
> With the introduction of BIO_NO_PAGE_REF we've used up all available bits
> in bio::bi_flags.
> 
> Convert the defines of the flags to an enum and add a BUILD_BUG_ON() call
> to make sure no-one adds a new one and thus overrides the BVEC_POOL_IDX
> causing crashes.
> 
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> 
> ---
> This used to be part of my bio patchset but as it's a) not clear why we
> end up calling bio_put() on the on-stack bio and b) the needed prep patch
> for the fix introduces a regression, I've decided to sent this patch out
> as it's valid on it's own.
> 
> I dropped Hannes' and Christoph's R-b though, as the context changed.
> ---
>   block/bio.c               |  3 +++
>   include/linux/blk_types.h | 29 ++++++++++++++++-------------
>   2 files changed, 19 insertions(+), 13 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke            Teamlead Storage & Networking
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