[PATCH 4.0 145/148] UBI: block: Add missing cache flushes

Greg Kroah-Hartman
2015-06-03T12:36:25Z

From: Kevin Cernekee <cernekee@chromium.org>

commit 98fb1ffd8154890d7051750e61ff5548c3ee2ab2 upstream.

Block drivers are responsible for calling flush_dcache_page() on each
BIO request. This operation keeps the I$ coherent with the D$ on
architectures that don't have hardware coherency support. Without this
flush, random crashes are seen when executing user programs from an ext4
filesystem backed by a ubiblock device.

This patch is based on the change implemented in commit 2d4dc890b5c8
("block: add helpers to run flush_dcache_page() against a bio and a
request's pages").

Fixes: 9d54c8a33eec ("UBI: R/O block driver on top of UBI volumes")
Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/mtd/ubi/block.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/mtd/ubi/block.c
+++ b/drivers/mtd/ubi/block.c
@@ -310,6 +310,8 @@ static void ubiblock_do_work(struct work
blk_rq_map_sg(req->q, req, pdu->usgl.sg);

ret = ubiblock_read(pdu);
+ rq_flush_dcache_pages(req);
+
blk_mq_end_request(req, ret);
}