block: separate priority boosting from REQ_META
Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.
All existing callers of REQ_META except for XFS are updated to also
set REQ_PRIO for now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 1ff5486..4c1a648 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -926,6 +926,9 @@
/*
* Reliable writes are used to implement Forced Unit Access and
* REQ_META accesses, and are supported only on MMCs.
+ *
+ * XXX: this really needs a good explanation of why REQ_META
+ * is treated special.
*/
bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||
(req->cmd_flags & REQ_META)) &&