From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH] bio allocation failure due to bio_get_nr_vecs()
Date: Fri, 11 May 2012 16:36:39 +0200
Message-ID: <4FAD23F7.2080605@kernel.dk>
References: <jognqm$o21$1@dough.gmane.org> <4FABF01E.7080303@itwm.fraunhofer.de> <4FAD18D4.3090102@itwm.fraunhofer.de>
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Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	linux-xfs@oss.sgi.com, sandeen@sandeen.net,
	Kent Overstreet <kent.overstreet@gmail.com>,
	Tejun Heo <tj@kernel.org>
To: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
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On 05/11/2012 03:49 PM, Bernd Schubert wrote:
> The number of bio_get_nr_vecs() is passed down via bio_alloc() to
> bvec_alloc_bs(), which fails the bio allocation if
> nr_iovecs > BIO_MAX_PAGES. For the underlying caller this causes an
> unexpected bio allocation failure.
> Limiting to queue_max_segments() is not sufficient, as max_segments
> also might be very large.
> 
> bvec_alloc_bs(gfp_mask, nr_iovecs, ) => NULL when nr_iovecs  > BIO_MAX_PAGES
> bio_alloc_bioset(gfp_mask, nr_iovecs, ...)
> bio_alloc(GFP_NOIO, nvecs)
> xfs_alloc_ioend_bio()

Thanks, looks sane. Applied.

-- 
Jens Axboe