From: Konstantin Khlebnikov khlebnikov@yandex-team.ru
[ Upstream commit e74d93e96d721c4297f2a900ad0191890d2fc2b0 ]
Field bdi->io_pages added in commit 9491ae4aade6 ("mm: don't cap request size based on read-ahead setting") removes unneeded split of read requests.
Stacked drivers do not call blk_queue_max_hw_sectors(). Instead they set limits of their devices by blk_set_stacking_limits() + disk_stack_limits(). Field bio->io_pages stays zero until user set max_sectors_kb via sysfs.
This patch updates io_pages after merging limits in disk_stack_limits().
Commit c6d6e9b0f6b4 ("dm: do not allow readahead to limit IO size") fixed the same problem for device-mapper devices, this one fixes MD RAIDs.
Fixes: 9491ae4aade6 ("mm: don't cap request size based on read-ahead setting") Reviewed-by: Paul Menzel pmenzel@molgen.mpg.de Reviewed-by: Bob Liu bob.liu@oracle.com Signed-off-by: Konstantin Khlebnikov khlebnikov@yandex-team.ru Signed-off-by: Song Liu songliubraving@fb.com Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-settings.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/block/blk-settings.c b/block/blk-settings.c index 6c2faaa38cc1e..e0a744921ed3d 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -717,6 +717,9 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n", top, bottom); } + + t->backing_dev_info->io_pages = + t->limits.max_sectors >> (PAGE_SHIFT - 9); } EXPORT_SYMBOL(disk_stack_limits);