@@ -832,6 +832,18 @@ void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
/**
+ * blk_set_queue_depth - tell the block layer about the device queue depth
+ * @q: the request queue for the device
+ * @depth: queue depth
+ *
+ */
+void blk_set_queue_depth(struct request_queue *q, unsigned int depth)
+{
+ q->queue_depth = depth;
+}
+EXPORT_SYMBOL(blk_set_queue_depth);
+
+/**
* blk_queue_write_cache - configure queue's write cache
* @q: the request queue for the device
* @wc: write back cache on or off
@@ -621,6 +621,9 @@ int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
wmb();
}
+ if (sdev->request_queue)
+ blk_set_queue_depth(sdev->request_queue, depth);
+
return sdev->queue_depth;
}
EXPORT_SYMBOL(scsi_change_queue_depth);
@@ -315,6 +315,8 @@ struct request_queue {
struct blk_mq_ctx __percpu *queue_ctx;
unsigned int nr_queues;
+ unsigned int queue_depth;
+
/* hw dispatch queues */
struct blk_mq_hw_ctx **queue_hw_ctx;
unsigned int nr_hw_queues;
@@ -681,6 +683,14 @@ static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
return false;
}
+static inline unsigned int blk_queue_depth(struct request_queue *q)
+{
+ if (q->queue_depth)
+ return q->queue_depth;
+
+ return q->nr_requests;
+}
+
/*
* q->prep_rq_fn return values
*/
@@ -984,6 +994,7 @@ extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
+extern void blk_set_queue_depth(struct request_queue *q, unsigned int depth);
extern void blk_set_default_limits(struct queue_limits *lim);
extern void blk_set_stacking_limits(struct queue_limits *lim);
extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
For blk-mq, ->nr_requests does track queue depth, at least at init time. But for the older queue paths, it's simply a soft setting. On top of that, it's generally larger than the hardware setting on purpose, to allow backup of requests for merging. Fill a hole in struct request with a 'queue_depth' member, that drivers can call to more closely inform the block layer of the real queue depth. Signed-off-by: Jens Axboe <axboe@fb.com> --- block/blk-settings.c | 12 ++++++++++++ drivers/scsi/scsi.c | 3 +++ include/linux/blkdev.h | 11 +++++++++++ 3 files changed, 26 insertions(+)