[ 54/73] block: add blk_queue_dead()

[Ben Hutchings <ben@decadent.org.uk>]

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tejun Heo <tj@kernel.org>

commit 34f6055c80285e4efb3f602a9119db75239744dc upstream.

There are a number of QUEUE_FLAG_DEAD tests.  Add blk_queue_dead()
macro and use it.

This patch doesn't introduce any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 block/blk-core.c       |    6 +++---
 block/blk-exec.c       |    2 +-
 block/blk-sysfs.c      |    4 ++--
 block/blk-throttle.c   |    4 ++--
 block/blk.h            |    2 +-
 include/linux/blkdev.h |    1 +
 6 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 435af23..b5ed4f4 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -608,7 +608,7 @@ EXPORT_SYMBOL(blk_init_allocated_queue_node);
 
 int blk_get_queue(struct request_queue *q)
 {
-	if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
+	if (likely(!blk_queue_dead(q))) {
 		kobject_get(&q->kobj);
 		return 0;
 	}
@@ -755,7 +755,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
 	const bool is_sync = rw_is_sync(rw_flags) != 0;
 	int may_queue;
 
-	if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
+	if (unlikely(blk_queue_dead(q)))
 		return NULL;
 
 	may_queue = elv_may_queue(q, rw_flags);
@@ -875,7 +875,7 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags,
 		struct io_context *ioc;
 		struct request_list *rl = &q->rq;
 
-		if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
+		if (unlikely(blk_queue_dead(q)))
 			return NULL;
 
 		prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
diff --git a/block/blk-exec.c b/block/blk-exec.c
index a1ebceb..6053285 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -50,7 +50,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
 {
 	int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
 
-	if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
+	if (unlikely(blk_queue_dead(q))) {
 		rq->errors = -ENXIO;
 		if (rq->end_io)
 			rq->end_io(rq, rq->errors);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index e7f9f65..f0b2ca8 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -425,7 +425,7 @@ queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 	if (!entry->show)
 		return -EIO;
 	mutex_lock(&q->sysfs_lock);
-	if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
+	if (blk_queue_dead(q)) {
 		mutex_unlock(&q->sysfs_lock);
 		return -ENOENT;
 	}
@@ -447,7 +447,7 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
 
 	q = container_of(kobj, struct request_queue, kobj);
 	mutex_lock(&q->sysfs_lock);
-	if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
+	if (blk_queue_dead(q)) {
 		mutex_unlock(&q->sysfs_lock);
 		return -ENOENT;
 	}
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 4553245..5eed6a7 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -310,7 +310,7 @@ static struct throtl_grp * throtl_get_tg(struct throtl_data *td)
 	struct request_queue *q = td->queue;
 
 	/* no throttling for dead queue */
-	if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
+	if (unlikely(blk_queue_dead(q)))
 		return NULL;
 
 	rcu_read_lock();
@@ -335,7 +335,7 @@ static struct throtl_grp * throtl_get_tg(struct throtl_data *td)
 	spin_lock_irq(q->queue_lock);
 
 	/* Make sure @q is still alive */
-	if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
+	if (unlikely(blk_queue_dead(q))) {
 		kfree(tg);
 		return NULL;
 	}
diff --git a/block/blk.h b/block/blk.h
index 3f6551b..e38691d 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -85,7 +85,7 @@ static inline struct request *__elv_next_request(struct request_queue *q)
 			q->flush_queue_delayed = 1;
 			return NULL;
 		}
-		if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
+		if (unlikely(blk_queue_dead(q)) ||
 		    !q->elevator->ops->elevator_dispatch_fn(q, 0))
 			return NULL;
 	}
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8a6b51b..783f97c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -481,6 +481,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 
 #define blk_queue_tagged(q)	test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 #define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
+#define blk_queue_dead(q)	test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 #define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 #define blk_queue_noxmerges(q)	\
 	test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)