No functional changes in this patch, we just add four flags
that will be used to denote a stream type, and ensure that we
don't merge across different stream types.
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
block/blk-merge.c | 16 ++++++++++++++++
include/linux/blk_types.h | 11 +++++++++++
2 files changed, 27 insertions(+)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 3990ae406341..7d299df3b12b 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -693,6 +693,14 @@ static struct request *attempt_merge(struct request_queue *q,
return NULL;
/*
+ * Don't allow merge of different streams, or for a stream with
+ * non-stream IO.
+ */
+ if ((req->cmd_flags & REQ_WRITE_LIFE_MASK) !=
+ (next->cmd_flags & REQ_WRITE_LIFE_MASK))
+ return NULL;
+
+ /*
* If we are allowed to merge, then append bio list
* from next to rq and release next. merge_requests_fn
* will have updated segment counts, update sector
@@ -811,6 +819,14 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
!blk_write_same_mergeable(rq->bio, bio))
return false;
+ /*
+ * Don't allow merge of different streams, or for a stream with
+ * non-stream IO.
+ */
+ if ((rq->cmd_flags & REQ_WRITE_LIFE_MASK) !=
+ (bio->bi_opf & REQ_WRITE_LIFE_MASK))
+ return false;
+
return true;
}
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 61339bc44400..57d1eb530799 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -201,6 +201,10 @@ enum req_flag_bits {
__REQ_PREFLUSH, /* request for cache flush */
__REQ_RAHEAD, /* read ahead, can fail anytime */
__REQ_BACKGROUND, /* background IO */
+ __REQ_WRITE_SHORT, /* short life time write */
+ __REQ_WRITE_MEDIUM, /* medium life time write */
+ __REQ_WRITE_LONG, /* long life time write */
+ __REQ_WRITE_EXTREME, /* extremely long life time write */
/* command specific flags for REQ_OP_WRITE_ZEROES: */
__REQ_NOUNMAP, /* do not free blocks when zeroing */
@@ -221,6 +225,13 @@ enum req_flag_bits {
#define REQ_PREFLUSH (1ULL << __REQ_PREFLUSH)
#define REQ_RAHEAD (1ULL << __REQ_RAHEAD)
#define REQ_BACKGROUND (1ULL << __REQ_BACKGROUND)
+#define REQ_WRITE_SHORT (1ULL << __REQ_WRITE_SHORT)
+#define REQ_WRITE_MEDIUM (1ULL << __REQ_WRITE_MEDIUM)
+#define REQ_WRITE_LONG (1ULL << __REQ_WRITE_LONG)
+#define REQ_WRITE_EXTREME (1ULL << __REQ_WRITE_EXTREME)
+
+#define REQ_WRITE_LIFE_MASK (REQ_WRITE_SHORT | REQ_WRITE_MEDIUM | \
+ REQ_WRITE_LONG | REQ_WRITE_EXTREME)
#define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP)
--
2.7.4
