From: Jeff Dike <jdike@addtoit.com>
To: stable@kernel.org
Cc: LKML <linux-kernel@vger.kernel.org>,
uml-devel <user-mode-linux-devel@lists.sourceforge.net>
Subject: [uml-devel] [PATCH] UML - limit requests on COW devices to 32 sectors
Date: Tue, 10 Jul 2007 12:49:02 -0400 [thread overview]
Message-ID: <20070710164902.GA7820@c2.user-mode-linux.org> (raw)
COWed devices can't handle more than 32 (64 on x86_64) sectors in one
request due to the size of the bitmap being carried around in the
io_thread_req.
Enforce that by telling the block layer not to put too many sectors in
requests to COWed devices.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
--
arch/um/drivers/ubd_kern.c | 2 ++
1 file changed, 2 insertions(+)
Index: linux-2.6.17/arch/um/drivers/ubd_kern.c
===================================================================
--- linux-2.6.17.orig/arch/um/drivers/ubd_kern.c 2007-07-09 08:53:09.000000000 -0400
+++ linux-2.6.17/arch/um/drivers/ubd_kern.c 2007-07-09 18:08:33.000000000 -0400
@@ -712,6 +712,8 @@ static int ubd_add(int n, char **error_o
ubd_dev->queue->queuedata = ubd_dev;
blk_queue_max_hw_segments(ubd_dev->queue, MAX_SG);
+ if(ubd_dev->cow.file != NULL)
+ blk_queue_max_sectors(ubd_dev->queue, 8 * sizeof(long));
err = ubd_disk_register(MAJOR_NR, ubd_dev->size, n, &ubd_gendisk[n]);
if(err){
*error_out = "Failed to register device";
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WARNING: multiple messages have this Message-ID (diff)
From: Jeff Dike <jdike@addtoit.com>
To: stable@kernel.org
Cc: LKML <linux-kernel@vger.kernel.org>,
uml-devel <user-mode-linux-devel@lists.sourceforge.net>
Subject: [PATCH] UML - limit requests on COW devices to 32 sectors
Date: Tue, 10 Jul 2007 12:49:02 -0400 [thread overview]
Message-ID: <20070710164902.GA7820@c2.user-mode-linux.org> (raw)
COWed devices can't handle more than 32 (64 on x86_64) sectors in one
request due to the size of the bitmap being carried around in the
io_thread_req.
Enforce that by telling the block layer not to put too many sectors in
requests to COWed devices.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
--
arch/um/drivers/ubd_kern.c | 2 ++
1 file changed, 2 insertions(+)
Index: linux-2.6.17/arch/um/drivers/ubd_kern.c
===================================================================
--- linux-2.6.17.orig/arch/um/drivers/ubd_kern.c 2007-07-09 08:53:09.000000000 -0400
+++ linux-2.6.17/arch/um/drivers/ubd_kern.c 2007-07-09 18:08:33.000000000 -0400
@@ -712,6 +712,8 @@ static int ubd_add(int n, char **error_o
ubd_dev->queue->queuedata = ubd_dev;
blk_queue_max_hw_segments(ubd_dev->queue, MAX_SG);
+ if(ubd_dev->cow.file != NULL)
+ blk_queue_max_sectors(ubd_dev->queue, 8 * sizeof(long));
err = ubd_disk_register(MAJOR_NR, ubd_dev->size, n, &ubd_gendisk[n]);
if(err){
*error_out = "Failed to register device";
next reply other threads:[~2007-07-11 0:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-10 16:49 Jeff Dike [this message]
2007-07-10 16:49 ` [PATCH] UML - limit requests on COW devices to 32 sectors Jeff Dike
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