operations before calling end_that_request_last()! For an example of a user
of these helpers, see the IDE tagged command queueing support.
-Certain hardware conditions may dictate a need to invalidate the block tag
-queue. For instance, on IDE any tagged request error needs to clear both
-the hardware and software block queue and enable the driver to sanely restart
-all the outstanding requests. There's a third helper to do that:
-
- blk_queue_invalidate_tags(struct request_queue *q)
-
- Clear the internal block tag queue and re-add all the pending requests
- to the request queue. The driver will receive them again on the
- next request_fn run, just like it did the first time it encountered
- them.
-
3.2.5.2 Tag info
Some block functions exist to query current tag status or to go from a
Most of the above is simple and straight forward, however busy_list may need
a bit of explaining. Normally we don't care too much about request ordering,
but in the event of any barrier requests in the tag queue we need to ensure
-that requests are restarted in the order they were queue. This may happen
-if the driver needs to use blk_queue_invalidate_tags().
+that requests are restarted in the order they were queue.
3.3 I/O Submission
*/
q->queue_tags = tags;
queue_flag_set_unlocked(QUEUE_FLAG_QUEUED, q);
- INIT_LIST_HEAD(&q->tag_busy_list);
return 0;
}
EXPORT_SYMBOL(blk_queue_init_tags);
rq->tag = tag;
bqt->tag_index[tag] = rq;
blk_start_request(rq);
- list_add(&rq->queuelist, &q->tag_busy_list);
return 0;
}
EXPORT_SYMBOL(blk_queue_start_tag);
-
-/**
- * blk_queue_invalidate_tags - invalidate all pending tags
- * @q: the request queue for the device
- *
- * Description:
- * Hardware conditions may dictate a need to stop all pending requests.
- * In this case, we will safely clear the block side of the tag queue and
- * readd all requests to the request queue in the right order.
- **/
-void blk_queue_invalidate_tags(struct request_queue *q)
-{
- struct list_head *tmp, *n;
-
- lockdep_assert_held(q->queue_lock);
-
- list_for_each_safe(tmp, n, &q->tag_busy_list)
- blk_requeue_request(q, list_entry_rq(tmp));
-}
-EXPORT_SYMBOL(blk_queue_invalidate_tags);
unsigned int dma_alignment;
struct blk_queue_tag *queue_tags;
- struct list_head tag_busy_list;
unsigned int nr_sorted;
unsigned int in_flight[2];
extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int);
extern void blk_queue_free_tags(struct request_queue *);
extern int blk_queue_resize_tags(struct request_queue *, int);
-extern void blk_queue_invalidate_tags(struct request_queue *);
extern struct blk_queue_tag *blk_init_tags(int, int);
extern void blk_free_tags(struct blk_queue_tag *);