[dm-devel] [PATCH] block: properly stack underlying max_segment_size to DM device
Jens Axboe
axboe at kernel.dk
Fri Oct 18 15:46:10 UTC 2013
On Fri, Oct 18 2013, Mike Snitzer wrote:
> Without this patch all DM devices will default to BLK_MAX_SEGMENT_SIZE
> (65536) even if the underlying device(s) have a larger value -- this is
> due to blk_stack_limits() using min_not_zero() when stacking the
> max_segment_size limit.
>
> # cat /sys/block/sda/queue/max_segment_size
> 1073741824
>
> # cat /sys/block/dm-0/queue/max_segment_size
> before patch:
> 65536
>
> after patch:
> 1073741824
>
> Reported-by: Lukasz Flis <l.flis at cyfronet.pl>
> Signed-off-by: Mike Snitzer <snitzer at redhat.com>
> Cc: stable at vger.kernel.org # v3.3+
> ---
> block/blk-settings.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index c50ecf0..29f28bb 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -143,6 +143,7 @@ void blk_set_stacking_limits(struct queue_limits *lim)
> /* Inherit limits from component devices */
> lim->discard_zeroes_data = 1;
> lim->max_segments = USHRT_MAX;
> + lim->max_segment_size = UINT_MAX;
> lim->max_hw_sectors = UINT_MAX;
> lim->max_sectors = UINT_MAX;
> lim->max_write_same_sectors = UINT_MAX;
Thanks, applied for 3.13.
--
Jens Axboe
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