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Date: Tue, 31 Jan 2012 06:57:16 -0500
From: Christoph Hellwig <hch@infradead.org>
To: Wu Fengguang <wfg@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>, Shaohua Li <shaohua.li@intel.com>,
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        Eric Dumazet <eric.dumazet@gmail.com>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH] fix readahead pipeline break caused by block plug
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On Tue, Jan 31, 2012 at 07:42:56PM +0800, Wu Fengguang wrote:
> > So what?  Better do a bit more work now and keep the damn thing
> > maintainable.
> 
> What if we add a wrapper function for doing
> 
>         blk_start_plug(&plug);
>         ->direct_IO()
>         blk_finish_plug(&plug);

No.  Just put it into __blockdev_direct_IO - a quick 2 minute audit of
the kernel source shows that is in fact the only ->direct_IO instance
which ever submits block I/O anyway.