Messages in this thread Patch in this message | | | Date | Fri, 13 Jul 2007 10:37:55 -0400 | From | Jeff Dike <> | Subject | [PATCH 2/3] UML - Limit request size on COWed devices |
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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"; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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