From: Omar Sandoval <osandov@fb.com>
Date: Thu, 24 Aug 2017 00:03:42 -0700
Subject: [PATCH] loop: set physical block size to PAGE_SIZE
Git-commit: 6c6b6f28b3335fd85ec833ee0005d9c9dca6c003
Patch-mainline: v4.14-rc1
References: bsc#1104967,FATE#325924
The physical block size is "the lowest possible sector size that the
hardware can operate on without reverting to read-modify-write
operations" (from the comment on blk_queue_physical_block_size()). Since
loop does buffered I/O on the backing file by default, the RMW unit is a
page. This isn't the case for direct I/O mode, but let's keep it simple.
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/block/loop.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index efad2d46a018..e3f190016d4f 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1764,6 +1764,8 @@ static int loop_add(struct loop_device **l, int i)
}
lo->lo_queue->queuedata = lo;
+ blk_queue_physical_block_size(lo->lo_queue, PAGE_SIZE);
+
/*
* It doesn't make sense to enable merge because the I/O
* submitted to backing file is handled page by page.
--
2.16.4