From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxx>
Reviewed-by: Bob Liu <bob.liu@xxxxxxxxxx>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Signed-off-by: Song Liu <songliubraving@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
block/blk-settings.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index c8eda2e7b91e4..be1dca0103a45 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -664,6 +664,9 @@ 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);
--
2.20.1
