From mboxrd@z Thu Jan  1 00:00:00 1970
From: Vladislav Bolkhovitin <vst@vlnb.net>
Subject: [PATCH][RFC 13/23]: Export of alloc_io_context() function
Date: Wed, 10 Dec 2008 21:49:19 +0300
Message-ID: <49400F2F.4050603@vlnb.net>
References: <494009D7.4020602@vlnb.net>
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Cc: James Bottomley <James.Bottomley@HansenPartnership.com>, Andrew Morton <akpm@linux-foundation.org>, FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>, Mike Christie <michaelc@cs.wisc.edu>, Jeff Garzik <jeff@garzik.org>, Boaz Harrosh <bharrosh@panasas.com>, Linus Torvalds <torvalds@linux-foundation.org>, linux-kernel@vger.kernel.org, scst-devel@lists.sourceforge.net, Bart Van Assche <bart.vanassche@gmail.com>, "Nicholas A. Bellinger" <nab@linux-iscsi.org>, Jens Axboe <jens.axboe@oracle.com>

This patch exports alloc_io_context() function. For performance reasons 
SCST queues commands using a pool of IO threads. It is considerably 
better for performance (>30% increase on sequential reads) if threads in 
  a pool have the same IO context. Since SCST can be built as a module, 
it needs alloc_io_context() function exported.

Signed-off-by: Vladislav Bolkhovitin <vst@vlnb.net>
---
  block/blk-ioc.c |    1 +
  1 file changed, 1 insertion(+)

diff -upkr linux-2.6.27.2/block/blk-ioc.c linux-2.6.27.2/block/blk-ioc.c
--- linux-2.6.27.2/block/blk-ioc.c	2008-10-10 02:13:53.000000000 +0400
+++ linux-2.6.27.2/block/blk-ioc.c	2008-11-25 21:27:01.000000000 +0300
@@ -105,6 +105,7 @@ struct io_context *alloc_io_context(gfp_
 
 	return ret;
 }
+EXPORT_SYMBOL(alloc_io_context);
 
 /*
  * If the current task has no IO context then create one and initialise it.