Re: [PATCH] block: ensure bdi->io_pages is always initialized

[OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>]

Jens Axboe <axboe@kernel.dk> writes:

> If a driver leaves the limit settings as the defaults, then we don't
> initialize bdi->io_pages. This means that file systems may need to
> work around bdi->io_pages == 0, which is somewhat messy.
>
> Initialize the default value just like we do for ->ra_pages.
>
> Cc: stable@vger.kernel.org
> Reported-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>

When queued to submit, please let us know to drop fatfs workaround
"fat-avoid-oops-when-bdi-io_pages==0.patch" in akpm series.

Thanks.

> ---
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index d9d632639bd1..10c08ac50697 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -539,6 +539,7 @@ struct request_queue *blk_alloc_queue(int node_id)
>  		goto fail_stats;
>  
>  	q->backing_dev_info->ra_pages = VM_READAHEAD_PAGES;
> +	q->backing_dev_info->io_pages = VM_READAHEAD_PAGES;
>  	q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;
>  	q->node = node_id;

-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>