block: add REQ_BACKGROUND
This adds a new request flag, REQ_BACKGROUND, that callers can use to
tell the block layer that this is background (non-urgent) IO.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index bb92102..562ac46 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -177,6 +177,7 @@ enum req_flag_bits {
__REQ_FUA, /* forced unit access */
__REQ_PREFLUSH, /* request for cache flush */
__REQ_RAHEAD, /* read ahead, can fail anytime */
+ __REQ_BACKGROUND, /* background IO */
__REQ_NR_BITS, /* stops here */
};
@@ -192,6 +193,7 @@ enum req_flag_bits {
#define REQ_FUA (1ULL << __REQ_FUA)
#define REQ_PREFLUSH (1ULL << __REQ_PREFLUSH)
#define REQ_RAHEAD (1ULL << __REQ_RAHEAD)
+#define REQ_BACKGROUND (1ULL << __REQ_BACKGROUND)
#define REQ_FAILFAST_MASK \
(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
