diff options
| -rw-r--r-- | block/blk-core.c | 28 | ||||
| -rw-r--r-- | block/blk.h | 1 | ||||
| -rw-r--r-- | block/elevator.c | 37 |
3 files changed, 40 insertions, 26 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index a3d2fdc8ed1c..149149dd7f7b 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -28,6 +28,7 @@ #include <linux/task_io_accounting_ops.h> #include <linux/fault-inject.h> #include <linux/list_sort.h> +#include <linux/delay.h> #define CREATE_TRACE_POINTS #include <trace/events/block.h> @@ -345,6 +346,33 @@ void blk_put_queue(struct request_queue *q) } EXPORT_SYMBOL(blk_put_queue); +/** + * blk_drain_queue - drain requests from request_queue + * @q: queue to drain + * + * Drain ELV_PRIV requests from @q. The caller is responsible for ensuring + * that no new requests which need to be drained are queued. + */ +void blk_drain_queue(struct request_queue *q) +{ + while (true) { + int nr_rqs; + + spin_lock_irq(q->queue_lock); + + elv_drain_elevator(q); + + __blk_run_queue(q); + nr_rqs = q->rq.elvpriv; + + spin_unlock_irq(q->queue_lock); + + if (!nr_rqs) + break; + msleep(10); + } +} + /* * Note: If a driver supplied the queue lock, it is disconnected * by this function. The actual state of the lock doesn't matter diff --git a/block/blk.h b/block/blk.h index da247ba2aeaf..2b66dc21a493 100644 --- a/block/blk.h +++ b/block/blk.h @@ -15,6 +15,7 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq, struct bio *bio); int blk_rq_append_bio(struct request_queue *q, struct request *rq, struct bio *bio); +void blk_drain_queue(struct request_queue *q); void blk_dequeue_request(struct request *rq); void __blk_queue_free_tags(struct request_queue *q); bool __blk_end_bidi_request(struct request *rq, int error, diff --git a/block/elevator.c b/block/elevator.c index cb332cb7ac6b..74a277ffed39 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -31,7 +31,6 @@ #include <linux/slab.h> #include <linux/init.h> #include <linux/compiler.h> -#include <linux/delay.h> #include <linux/blktrace_api.h> #include <linux/hash.h> #include <linux/uaccess.h> @@ -606,43 +605,35 @@ void elv_requeue_request(struct request_queue *q, struct request *rq) void elv_drain_elevator(struct request_queue *q) { static int printed; + + lockdep_assert_held(q->queue_lock); + while (q->elevator->ops->elevator_dispatch_fn(q, 1)) ; - if (q->nr_sorted == 0) - return; - if (printed++ < 10) { + if (q->nr_sorted && printed++ < 10) { printk(KERN_ERR "%s: forced dispatching is broken " "(nr_sorted=%u), please report this\n", q->elevator->elevator_type->elevator_name, q->nr_sorted); } } -/* - * Call with queue lock held, interrupts disabled - */ void elv_quiesce_start(struct request_queue *q) { if (!q->elevator) return; + spin_lock_irq(q->queue_lock); queue_flag_set(QUEUE_FLAG_ELVSWITCH, q); + spin_unlock_irq(q->queue_lock); - /* - * make sure we don't have any requests in flight - */ - elv_drain_elevator(q); - while (q->rq.elvpriv) { - __blk_run_queue(q); - spin_unlock_irq(q->queue_lock); - msleep(10); - spin_lock_irq(q->queue_lock); - elv_drain_elevator(q); - } + blk_drain_queue(q); } void elv_quiesce_end(struct request_queue *q) { + spin_lock_irq(q->queue_lock); queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); + spin_unlock_irq(q->queue_lock); } void __elv_add_request(struct request_queue *q, struct request *rq, int where) @@ -972,7 +963,6 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) /* * Turn on BYPASS and drain all requests w/ elevator private data */ - spin_lock_irq(q->queue_lock); elv_quiesce_start(q); /* @@ -983,8 +973,8 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) /* * attach and start new elevator */ + spin_lock_irq(q->queue_lock); elevator_attach(q, e, data); - spin_unlock_irq(q->queue_lock); if (old_elevator->registered) { @@ -999,9 +989,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) * finally exit old elevator and turn off BYPASS. */ elevator_exit(old_elevator); - spin_lock_irq(q->queue_lock); elv_quiesce_end(q); - spin_unlock_irq(q->queue_lock); blk_add_trace_msg(q, "elv switch: %s", e->elevator_type->elevator_name); @@ -1015,10 +1003,7 @@ fail_register: elevator_exit(e); q->elevator = old_elevator; elv_register_queue(q); - - spin_lock_irq(q->queue_lock); - queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q); - spin_unlock_irq(q->queue_lock); + elv_quiesce_end(q); return err; } |