From: Pete Wyckoff <pw@osc.edu>
Date: Tue, 1 Jan 2008 15:23:02 +0000 (-0500)
Subject: block: allow queue dma_alignment of zero
X-Git-Tag: v2.6.25-rc1~1171^2~2
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=482eb689169948e9f4966fbae6be4d6bc0bfa818;p=linux-2.6

block: allow queue dma_alignment of zero

Let queue_dma_alignment return 0 if it was specifically set to 0.
This permits devices with no particular alignment restrictions to
use arbitrary user space buffers without copying.

Signed-off-by: Pete Wyckoff <pw@osc.edu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 49b7a4c31a..c7a3ab575c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -836,12 +836,7 @@ static inline int bdev_hardsect_size(struct block_device *bdev)
 
 static inline int queue_dma_alignment(struct request_queue *q)
 {
-	int retval = 511;
-
-	if (q && q->dma_alignment)
-		retval = q->dma_alignment;
-
-	return retval;
+	return q ? q->dma_alignment : 511;
 }
 
 /* assumes size > 256 */