3 files changed, 6 insertions, 4 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 1fdfc5621c83..33c3947d61e9 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -188,8 +188,8 @@ struct bio {
 #define bio_failfast(bio)       ((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
 #define bio_rw_ahead(bio)       ((bio)->bi_rw & (1 << BIO_RW_AHEAD))
 #define bio_rw_meta(bio)        ((bio)->bi_rw & (1 << BIO_RW_META))
-#define bio_empty_barrier(bio)  (bio_barrier(bio) && !bio_has_data(bio))
 #define bio_discard(bio)        ((bio)->bi_rw & (1 << BIO_RW_DISCARD))
+#define bio_empty_barrier(bio)  (bio_barrier(bio) && !bio_has_data(bio) && !bio_discard(bio))
 
 static inline unsigned int bio_cur_sectors(struct bio *bio)
 {
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 727886d25c4e..e9eb35c9bf26 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -541,7 +541,7 @@ enum {
 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
 #define blk_rq_started(rq)      ((rq)->cmd_flags & REQ_STARTED)
 
-#define blk_account_rq(rq)      (blk_rq_started(rq) && blk_fs_request(rq))
+#define blk_account_rq(rq)      (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq))) 
 
 #define blk_pm_suspend_request(rq)      ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
 #define blk_pm_resume_request(rq)       ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
@@ -598,7 +598,8 @@ static inline void blk_clear_queue_full(struct request_queue *q, int rw)
 #define RQ_NOMERGE_FLAGS        \
         (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
 #define rq_mergeable(rq)        \
-        (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
+        (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
+         (blk_discard_rq(rq) || blk_fs_request((rq))))
 
 /*
  * q->prep_rq_fn return values
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 88358ca6af25..860689f541b1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -87,7 +87,8 @@ extern int dir_notify_enable;
 #define WRITE_SYNC      (WRITE | (1 << BIO_RW_SYNC))
 #define SWRITE_SYNC     (SWRITE | (1 << BIO_RW_SYNC))
 #define WRITE_BARRIER   (WRITE | (1 << BIO_RW_BARRIER))
-#define WRITE_DISCARD   (WRITE | (1 << BIO_RW_DISCARD))
+#define DISCARD_NOBARRIER (1 << BIO_RW_DISCARD)
+#define DISCARD_BARRIER ((1 << BIO_RW_DISCARD) | (1 << BIO_RW_BARRIER))
 
 #define SEL_IN          1
 #define SEL_OUT         2