#include <trace/events/block.h>
#include "blk.h"
+#include "blk-cgroup.h"
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
*
* This function does not cancel any asynchronous activity arising
* out of elevator or throttling code. That would require elevaotor_exit()
- * and blk_throtl_exit() to be called with queue lock initialized.
+ * and blkcg_exit_queue() to be called with queue lock initialized.
*
*/
void blk_sync_queue(struct request_queue *q)
spin_lock_irq(q->queue_lock);
- elv_drain_elevator(q);
- if (drain_all)
- blk_throtl_drain(q);
+ /*
+ * The caller might be trying to drain @q before its
+ * elevator is initialized.
+ */
+ if (q->elevator)
+ elv_drain_elevator(q);
+
+ blkcg_drain_queue(q);
/*
* This function might be called on a queue which failed
- * driver init after queue creation. Some drivers
- * (e.g. fd) get unhappy in such cases. Kick queue iff
- * dispatch queue has something on it.
+ * driver init after queue creation or is not yet fully
+ * active yet. Some drivers (e.g. fd and loop) get unhappy
+ * in such cases. Kick queue iff dispatch queue has
+ * something on it and @q has request_fn set.
*/
- if (!list_empty(&q->queue_head))
+ if (!list_empty(&q->queue_head) && q->request_fn)
__blk_run_queue(q);
drain |= q->rq.elvpriv;
}
}
+/**
+ * blk_queue_bypass_start - enter queue bypass mode
+ * @q: queue of interest
+ *
+ * In bypass mode, only the dispatch FIFO queue of @q is used. This
+ * function makes @q enter bypass mode and drains all requests which were
+ * throttled or issued before. On return, it's guaranteed that no request
+ * is being throttled or has ELVPRIV set.
+ */
+void blk_queue_bypass_start(struct request_queue *q)
+{
+ spin_lock_irq(q->queue_lock);
+ q->bypass_depth++;
+ queue_flag_set(QUEUE_FLAG_BYPASS, q);
+ spin_unlock_irq(q->queue_lock);
+
+ blk_drain_queue(q, false);
+}
+EXPORT_SYMBOL_GPL(blk_queue_bypass_start);
+
+/**
+ * blk_queue_bypass_end - leave queue bypass mode
+ * @q: queue of interest
+ *
+ * Leave bypass mode and restore the normal queueing behavior.
+ */
+void blk_queue_bypass_end(struct request_queue *q)
+{
+ spin_lock_irq(q->queue_lock);
+ if (!--q->bypass_depth)
+ queue_flag_clear(QUEUE_FLAG_BYPASS, q);
+ WARN_ON_ONCE(q->bypass_depth < 0);
+ spin_unlock_irq(q->queue_lock);
+}
+EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
+
/**
* blk_cleanup_queue - shutdown a request queue
* @q: request queue to shutdown
queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
spin_lock_irq(lock);
+
+ /* dead queue is permanently in bypass mode till released */
+ q->bypass_depth++;
+ queue_flag_set(QUEUE_FLAG_BYPASS, q);
+
queue_flag_set(QUEUE_FLAG_NOMERGES, q);
queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
queue_flag_set(QUEUE_FLAG_DEAD, q);
spin_unlock_irq(lock);
mutex_unlock(&q->sysfs_lock);
- /*
- * Drain all requests queued before DEAD marking. The caller might
- * be trying to tear down @q before its elevator is initialized, in
- * which case we don't want to call into draining.
- */
- if (q->elevator)
- blk_drain_queue(q, true);
+ /* drain all requests queued before DEAD marking */
+ blk_drain_queue(q, true);
/* @q won't process any more request, flush async actions */
del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
if (err)
goto fail_id;
- if (blk_throtl_init(q))
- goto fail_id;
-
setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
laptop_mode_timer_fn, (unsigned long) q);
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
+ INIT_LIST_HEAD(&q->queue_head);
INIT_LIST_HEAD(&q->timeout_list);
INIT_LIST_HEAD(&q->icq_list);
+#ifdef CONFIG_BLK_CGROUP
+ INIT_LIST_HEAD(&q->blkg_list);
+#endif
INIT_LIST_HEAD(&q->flush_queue[0]);
INIT_LIST_HEAD(&q->flush_queue[1]);
INIT_LIST_HEAD(&q->flush_data_in_flight);
*/
q->queue_lock = &q->__queue_lock;
+ if (blkcg_init_queue(q))
+ goto fail_id;
+
return q;
fail_id:
if (rq->cmd_flags & REQ_ELVPRIV) {
elv_put_request(q, rq);
if (rq->elv.icq)
- put_io_context(rq->elv.icq->ioc, q);
+ put_io_context(rq->elv.icq->ioc);
}
mempool_free(rq, q->rq.rq_pool);
* Also, lookup icq while holding queue_lock. If it doesn't exist,
* it will be created after releasing queue_lock.
*/
- if (blk_rq_should_init_elevator(bio) &&
- !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags)) {
+ if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
rw_flags |= REQ_ELVPRIV;
rl->elvpriv++;
if (et->icq_cache && ioc)
spin_unlock_irq(q->queue_lock);
/* create icq if missing */
- if (unlikely(et->icq_cache && !icq))
+ if ((rw_flags & REQ_ELVPRIV) && unlikely(et->icq_cache && !icq)) {
icq = ioc_create_icq(q, gfp_mask);
+ if (!icq)
+ goto fail_icq;
+ }
- /* rqs are guaranteed to have icq on elv_set_request() if requested */
- if (likely(!et->icq_cache || icq))
- rq = blk_alloc_request(q, icq, rw_flags, gfp_mask);
+ rq = blk_alloc_request(q, icq, rw_flags, gfp_mask);
+fail_icq:
if (unlikely(!rq)) {
/*
* Allocation failed presumably due to memory. Undo anything
req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
drive_stat_acct(req, 0);
- elv_bio_merged(q, req, bio);
return true;
}
req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
drive_stat_acct(req, 0);
- elv_bio_merged(q, req, bio);
return true;
}
* on %current's plugged list. Returns %true if merge was successful,
* otherwise %false.
*
- * This function is called without @q->queue_lock; however, elevator is
- * accessed iff there already are requests on the plugged list which in
- * turn guarantees validity of the elevator.
- *
- * Note that, on successful merge, elevator operation
- * elevator_bio_merged_fn() will be called without queue lock. Elevator
- * must be ready for this.
+ * Plugging coalesces IOs from the same issuer for the same purpose without
+ * going through @q->queue_lock. As such it's more of an issuing mechanism
+ * than scheduling, and the request, while may have elvpriv data, is not
+ * added on the elevator at this point. In addition, we don't have
+ * reliable access to the elevator outside queue lock. Only check basic
+ * merging parameters without querying the elevator.
*/
static bool attempt_plug_merge(struct request_queue *q, struct bio *bio,
unsigned int *request_count)
(*request_count)++;
- if (rq->q != q)
+ if (rq->q != q || !blk_rq_merge_ok(rq, bio))
continue;
- el_ret = elv_try_merge(rq, bio);
+ el_ret = blk_try_merge(rq, bio);
if (el_ret == ELEVATOR_BACK_MERGE) {
ret = bio_attempt_back_merge(q, rq, bio);
if (ret)
el_ret = elv_merge(q, &req, bio);
if (el_ret == ELEVATOR_BACK_MERGE) {
if (bio_attempt_back_merge(q, req, bio)) {
+ elv_bio_merged(q, req, bio);
if (!attempt_back_merge(q, req))
elv_merged_request(q, req, el_ret);
goto out_unlock;
}
} else if (el_ret == ELEVATOR_FRONT_MERGE) {
if (bio_attempt_front_merge(q, req, bio)) {
+ elv_bio_merged(q, req, bio);
if (!attempt_front_merge(q, req))
elv_merged_request(q, req, el_ret);
goto out_unlock;
projects / karo-tx-linux.git / blobdiff