block: make queue flags non-atomic
We can save some atomic ops in the IO path, if we clearly define
the rules of how to modify the queue flags.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c5065e3..8ca481c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -408,6 +408,30 @@
#define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
#define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
+static inline void queue_flag_set_unlocked(unsigned int flag,
+ struct request_queue *q)
+{
+ __set_bit(flag, &q->queue_flags);
+}
+
+static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
+{
+ WARN_ON_ONCE(!spin_is_locked(q->queue_lock));
+ __set_bit(flag, &q->queue_flags);
+}
+
+static inline void queue_flag_clear_unlocked(unsigned int flag,
+ struct request_queue *q)
+{
+ __clear_bit(flag, &q->queue_flags);
+}
+
+static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
+{
+ WARN_ON_ONCE(!spin_is_locked(q->queue_lock));
+ __clear_bit(flag, &q->queue_flags);
+}
+
enum {
/*
* Hardbarrier is supported with one of the following methods.
@@ -496,17 +520,17 @@
static inline void blk_set_queue_full(struct request_queue *q, int rw)
{
if (rw == READ)
- set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
+ queue_flag_set(QUEUE_FLAG_READFULL, q);
else
- set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
+ queue_flag_set(QUEUE_FLAG_WRITEFULL, q);
}
static inline void blk_clear_queue_full(struct request_queue *q, int rw)
{
if (rw == READ)
- clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
+ queue_flag_clear(QUEUE_FLAG_READFULL, q);
else
- clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
+ queue_flag_clear(QUEUE_FLAG_WRITEFULL, q);
}
@@ -626,6 +650,7 @@
extern void blk_stop_queue(struct request_queue *q);
extern void blk_sync_queue(struct request_queue *q);
extern void __blk_stop_queue(struct request_queue *q);
+extern void __blk_run_queue(struct request_queue *);
extern void blk_run_queue(struct request_queue *);
extern void blk_start_queueing(struct request_queue *);
extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long);