From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org,
Liu Yiding <liuyd.fnst@cn.fujitsu.com>,
kernel test robot <rong.a.chen@intel.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Christoph Hellwig <hch@lst.de>,
stable@vger.kernel.org
Subject: Re: [PATCH] block: fix .bi_size overflow
Date: Mon, 1 Jul 2019 08:36:13 +0200 [thread overview]
Message-ID: <20190701063613.GA20733@lst.de> (raw)
In-Reply-To: <20190701041644.16052-1-ming.lei@redhat.com>
On Mon, Jul 01, 2019 at 12:16:44PM +0800, Ming Lei wrote:
> 'bio->bi_iter.bi_size' is 'unsigned int', which at most hold 4G - 1
> bytes.
>
> Before 07173c3ec276 ("block: enable multipage bvecs"), one bio can
> include very limited pages, and usually at most 256, so the fs bio
> size won't be bigger than 1M bytes most of times.
>
> Since we support multi-page bvec, in theory one fs bio really can
> be added > 1M pages, especially in case of hugepage, or big writeback
> in case of huge dirty pages. Then there is chance in which .bi_size
> is overflowed.
>
> Fixes this issue by adding bio_will_full() which checks if the added
> segment may overflow .bi_size.
Can you please just add the argument to bio_full? bio_will_full sounds
rather odd.
Maybe also add a kerneldoc comment to the new bio_full to explain
it. Otherwise this looks fine to me.
next prev parent reply other threads:[~2019-07-01 6:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-01 4:16 [PATCH] block: fix .bi_size overflow Ming Lei
2019-07-01 6:36 ` Christoph Hellwig [this message]
2019-07-01 6:46 ` Ming Lei
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