/*
* We can hit rq == NULL here, because the tagging functions
- * test and set the bit before assining ->rqs[].
+ * test and set the bit before assigning ->rqs[].
*/
if (rq && rq->q == hctx->queue)
iter_data->fn(hctx, rq, iter_data->data, reserved);
return true;
}
+/**
+ * bt_for_each - iterate over the requests associated with a hardware queue
+ * @hctx: Hardware queue to examine.
+ * @bt: sbitmap to examine. This is either the breserved_tags member
+ * or the bitmap_tags member of struct blk_mq_tags.
+ * @fn: Pointer to the function that will be called for each request
+ * associated with @hctx that has been assigned a driver tag.
+ * @fn will be called as follows: @fn(@hctx, rq, @data, @reserved)
+ * where rq is a pointer to a request.
+ * @data: Will be passed as third argument to @fn.
+ * @reserved: Indicates whether @bt is the breserved_tags member or the
+ * bitmap_tags member of struct blk_mq_tags.
+ */
static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt,
busy_iter_fn *fn, void *data, bool reserved)
{
return true;
}
+/**
+ * bt_tags_for_each - iterate over the requests in a tag map
+ * @tags: Tag map to iterate over.
+ * @bt: sbitmap to examine. This is either the breserved_tags member
+ * or the bitmap_tags member of struct blk_mq_tags.
+ * @fn: Pointer to the function that will be called for each started
+ * request. @fn will be called as follows: @fn(rq, @data,
+ * @reserved) where rq is a pointer to a request.
+ * @data: Will be passed as second argument to @fn.
+ * @reserved: Indicates whether @bt is the breserved_tags member or the
+ * bitmap_tags member of struct blk_mq_tags.
+ */
static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
busy_tag_iter_fn *fn, void *data, bool reserved)
{
sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
}
+/**
+ * blk_mq_all_tag_busy_iter - iterate over all started requests in a tag map
+ * @tags: Tag map to iterate over.
+ * @fn: Pointer to the function that will be called for each started
+ * request. @fn will be called as follows: @fn(rq, @priv,
+ * reserved) where rq is a pointer to a request. 'reserved'
+ * indicates whether or not @rq is a reserved request.
+ * @priv: Will be passed as second argument to @fn.
+ */
static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
busy_tag_iter_fn *fn, void *priv)
{
bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, false);
}
+/**
+ * blk_mq_tagset_busy_iter - iterate over all started requests in a tag set
+ * @tagset: Tag set to iterate over.
+ * @fn: Pointer to the function that will be called for each started
+ * request. @fn will be called as follows: @fn(rq, @priv,
+ * reserved) where rq is a pointer to a request. 'reserved'
+ * indicates whether or not @rq is a reserved request.
+ * @priv: Will be passed as second argument to @fn.
+ */
void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
busy_tag_iter_fn *fn, void *priv)
{
}
EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
+/**
+ * blk_mq_queue_tag_busy_iter - iterate over all requests with a driver tag
+ * @q: Request queue to examine.
+ * @fn: Pointer to the function that will be called for each request
+ * on @q. @fn will be called as follows: @fn(hctx, rq, @priv,
+ * reserved) where rq is a pointer to a request and hctx points
+ * to the hardware queue associated with the request. 'reserved'
+ * indicates whether or not @rq is a reserved request.
+ * @priv: Will be passed as third argument to @fn.
+ *
+ * Note: if @q->tag_set is shared with other request queues then @fn will be
+ * called for all requests on all queues that share that tag set and not only
+ * for requests associated with @q.
+ */
void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
void *priv)
{
int i;
/*
- * __blk_mq_update_nr_hw_queues will update the nr_hw_queues and
- * queue_hw_ctx after freeze the queue. So we could use q_usage_counter
- * to avoid race with it. __blk_mq_update_nr_hw_queues will users
- * synchronize_rcu to ensure all of the users go out of the critical
- * section below and see zeroed q_usage_counter.
+ * __blk_mq_update_nr_hw_queues() updates nr_hw_queues and queue_hw_ctx
+ * while the queue is frozen. So we can use q_usage_counter to avoid
+ * racing with it. __blk_mq_update_nr_hw_queues() uses
+ * synchronize_rcu() to ensure this function left the critical section
+ * below.
*/
- rcu_read_lock();
- if (percpu_ref_is_zero(&q->q_usage_counter)) {
- rcu_read_unlock();
+ if (!percpu_ref_tryget(&q->q_usage_counter))
return;
- }
queue_for_each_hw_ctx(q, hctx, i) {
struct blk_mq_tags *tags = hctx->tags;
/*
- * If not software queues are currently mapped to this
+ * If no software queues are currently mapped to this
* hardware queue, there's nothing to check
*/
if (!blk_mq_hw_queue_mapped(hctx))
bt_for_each(hctx, &tags->breserved_tags, fn, priv, true);
bt_for_each(hctx, &tags->bitmap_tags, fn, priv, false);
}
- rcu_read_unlock();
+ blk_queue_exit(q);
}
static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
projects / linux-2.6-microblaze.git / blobdiff