diff options
| -rw-r--r-- | drivers/md/dm.c | 158 |
1 files changed, 14 insertions, 144 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 30f5dc8e52b..634b1daab2d 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -178,9 +178,6 @@ struct mapped_device { /* forced geometry settings */ struct hd_geometry geometry; - /* marker of flush suspend for request-based dm */ - struct request suspend_rq; - /* For saving the address of __make_request for request based dm */ make_request_fn *saved_make_request_fn; @@ -1471,11 +1468,6 @@ static struct request *clone_rq(struct request *rq, struct mapped_device *md, return clone; } -static int dm_rq_flush_suspending(struct mapped_device *md) -{ - return !md->suspend_rq.special; -} - /* * Called with the queue lock held. */ @@ -1484,14 +1476,6 @@ static int dm_prep_fn(struct request_queue *q, struct request *rq) struct mapped_device *md = q->queuedata; struct request *clone; - if (unlikely(rq == &md->suspend_rq)) { - if (dm_rq_flush_suspending(md)) - return BLKPREP_OK; - else - /* The flush suspend was interrupted */ - return BLKPREP_KILL; - } - if (unlikely(rq->special)) { DMWARN("Already has something in rq->special."); return BLKPREP_KILL; @@ -1560,27 +1544,15 @@ static void dm_request_fn(struct request_queue *q) struct request *rq; /* - * For noflush suspend, check blk_queue_stopped() to immediately - * quit I/O dispatching. + * For suspend, check blk_queue_stopped() and don't increment + * the number of in-flight I/Os after the queue is stopped + * in dm_suspend(). */ while (!blk_queue_plugged(q) && !blk_queue_stopped(q)) { rq = blk_peek_request(q); if (!rq) goto plug_and_out; - if (unlikely(rq == &md->suspend_rq)) { /* Flush suspend maker */ - if (queue_in_flight(q)) - /* Not quiet yet. Wait more */ - goto plug_and_out; - - /* This device should be quiet now */ - __stop_queue(q); - blk_start_request(rq); - __blk_end_request_all(rq, 0); - wake_up(&md->wait); - goto out; - } - ti = dm_table_find_target(map, blk_rq_pos(rq)); if (ti->type->busy && ti->type->busy(ti)) goto plug_and_out; @@ -2112,7 +2084,7 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible) smp_mb(); if (dm_request_based(md)) { spin_lock_irqsave(q->queue_lock, flags); - if (!queue_in_flight(q) && blk_queue_stopped(q)) { + if (!queue_in_flight(q)) { spin_unlock_irqrestore(q->queue_lock, flags); break; } @@ -2245,67 +2217,6 @@ out: return r; } -static void dm_rq_invalidate_suspend_marker(struct mapped_device *md) -{ - md->suspend_rq.special = (void *)0x1; -} - -static void dm_rq_abort_suspend(struct mapped_device *md, int noflush) -{ - struct request_queue *q = md->queue; - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - if (!noflush) - dm_rq_invalidate_suspend_marker(md); - __start_queue(q); - spin_unlock_irqrestore(q->queue_lock, flags); -} - -static void dm_rq_start_suspend(struct mapped_device *md, int noflush) -{ - struct request *rq = &md->suspend_rq; - struct request_queue *q = md->queue; - - if (noflush) - stop_queue(q); - else { - blk_rq_init(q, rq); - blk_insert_request(q, rq, 0, NULL); - } -} - -static int dm_rq_suspend_available(struct mapped_device *md, int noflush) -{ - int r = 1; - struct request *rq = &md->suspend_rq; - struct request_queue *q = md->queue; - unsigned long flags; - - if (noflush) - return r; - - /* The marker must be protected by queue lock if it is in use */ - spin_lock_irqsave(q->queue_lock, flags); - if (unlikely(rq->ref_count)) { - /* - * This can happen, when the previous flush suspend was - * interrupted, the marker is still in the queue and - * this flush suspend has been invoked, because we don't - * remove the marker at the time of suspend interruption. - * We have only one marker per mapped_device, so we can't - * start another flush suspend while it is in use. - */ - BUG_ON(!rq->special); /* The marker should be invalidated */ - DMWARN("Invalidating the previous flush suspend is still in" - " progress. Please retry later."); - r = 0; - } - spin_unlock_irqrestore(q->queue_lock, flags); - - return r; -} - /* * Functions to lock and unlock any filesystem running on the * device. @@ -2348,49 +2259,11 @@ static void unlock_fs(struct mapped_device *md) /* * Suspend mechanism in request-based dm. * - * After the suspend starts, further incoming requests are kept in - * the request_queue and deferred. - * Remaining requests in the request_queue at the start of suspend are flushed - * if it is flush suspend. - * The suspend completes when the following conditions have been satisfied, - * so wait for it: - * 1. q->in_flight is 0 (which means no in_flight request) - * 2. queue has been stopped (which means no request dispatching) - * - * - * Noflush suspend - * --------------- - * Noflush suspend doesn't need to dispatch remaining requests. - * So stop the queue immediately. Then, wait for all in_flight requests - * to be completed or requeued. - * - * To abort noflush suspend, start the queue. + * 1. Flush all I/Os by lock_fs() if needed. + * 2. Stop dispatching any I/O by stopping the request_queue. + * 3. Wait for all in-flight I/Os to be completed or requeued. * - * - * Flush suspend - * ------------- - * Flush suspend needs to dispatch remaining requests. So stop the queue - * after the remaining requests are completed. (Requeued request must be also - * re-dispatched and completed. Until then, we can't stop the queue.) - * - * During flushing the remaining requests, further incoming requests are also - * inserted to the same queue. To distinguish which requests are to be - * flushed, we insert a marker request to the queue at the time of starting - * flush suspend, like a barrier. - * The dispatching is blocked when the marker is found on the top of the queue. - * And the queue is stopped when all in_flight requests are completed, since - * that means the remaining requests are completely flushed. - * Then, the marker is removed from the queue. - * - * To abort flush suspend, we also need to take care of the marker, not only - * starting the queue. - * We don't remove the marker forcibly from the queue since it's against - * the block-layer manner. Instead, we put a invalidated mark on the marker. - * When the invalidated marker is found on the top of the queue, it is - * immediately removed from the queue, so it doesn't block dispatching. - * Because we have only one marker per mapped_device, we can't start another - * flush suspend until the invalidated marker is removed from the queue. - * So fail and return with -EBUSY in such a case. + * To abort suspend, start the request_queue. */ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) { @@ -2406,11 +2279,6 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) goto out_unlock; } - if (dm_request_based(md) && !dm_rq_suspend_available(md, noflush)) { - r = -EBUSY; - goto out_unlock; - } - map = dm_get_table(md); /* @@ -2424,8 +2292,10 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) dm_table_presuspend_targets(map); /* - * Flush I/O to the device. noflush supersedes do_lockfs, - * because lock_fs() needs to flush I/Os. + * Flush I/O to the device. + * Any I/O submitted after lock_fs() may not be flushed. + * noflush takes precedence over do_lockfs. + * (lock_fs() flushes I/Os and waits for them to complete.) */ if (!noflush && do_lockfs) { r = lock_fs(md); @@ -2457,7 +2327,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) flush_workqueue(md->wq); if (dm_request_based(md)) - dm_rq_start_suspend(md, noflush); + stop_queue(md->queue); /* * At this point no more requests are entering target request routines. @@ -2476,7 +2346,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) dm_queue_flush(md); if (dm_request_based(md)) - dm_rq_abort_suspend(md, noflush); + start_queue(md->queue); unlock_fs(md); goto out; /* pushback list is already flushed, so skip flush */ |