diff options
| -rw-r--r-- | drivers/md/dm-kcopyd.c | 54 |
1 files changed, 51 insertions, 3 deletions
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c index 5ad9231c8700..dad32f8bce7d 100644 --- a/drivers/md/dm-kcopyd.c +++ b/drivers/md/dm-kcopyd.c @@ -37,6 +37,13 @@ struct dm_kcopyd_client { unsigned int nr_pages; unsigned int nr_free_pages; + /* + * Block devices to unplug. + * Non-NULL pointer means that a block device has some pending requests + * and needs to be unplugged. + */ + struct block_device *unplug[2]; + struct dm_io_client *io_client; wait_queue_head_t destroyq; @@ -308,6 +315,31 @@ static int run_complete_job(struct kcopyd_job *job) return 0; } +/* + * Unplug the block device at the specified index. + */ +static void unplug(struct dm_kcopyd_client *kc, int rw) +{ + if (kc->unplug[rw] != NULL) { + blk_unplug(bdev_get_queue(kc->unplug[rw])); + kc->unplug[rw] = NULL; + } +} + +/* + * Prepare block device unplug. If there's another device + * to be unplugged at the same array index, we unplug that + * device first. + */ +static void prepare_unplug(struct dm_kcopyd_client *kc, int rw, + struct block_device *bdev) +{ + if (likely(kc->unplug[rw] == bdev)) + return; + unplug(kc, rw); + kc->unplug[rw] = bdev; +} + static void complete_io(unsigned long error, void *context) { struct kcopyd_job *job = (struct kcopyd_job *) context; @@ -345,7 +377,7 @@ static int run_io_job(struct kcopyd_job *job) { int r; struct dm_io_request io_req = { - .bi_rw = job->rw | REQ_UNPLUG, + .bi_rw = job->rw, .mem.type = DM_IO_PAGE_LIST, .mem.ptr.pl = job->pages, .mem.offset = job->offset, @@ -354,10 +386,16 @@ static int run_io_job(struct kcopyd_job *job) .client = job->kc->io_client, }; - if (job->rw == READ) + if (job->rw == READ) { r = dm_io(&io_req, 1, &job->source, NULL); - else + prepare_unplug(job->kc, READ, job->source.bdev); + } else { + if (job->num_dests > 1) + io_req.bi_rw |= REQ_UNPLUG; r = dm_io(&io_req, job->num_dests, job->dests, NULL); + if (!(io_req.bi_rw & REQ_UNPLUG)) + prepare_unplug(job->kc, WRITE, job->dests[0].bdev); + } return r; } @@ -435,10 +473,18 @@ static void do_work(struct work_struct *work) * Pages jobs when successful will jump onto the io jobs * list. io jobs call wake when they complete and it all * starts again. + * + * Note that io_jobs add block devices to the unplug array, + * this array is cleared with "unplug" calls. It is thus + * forbidden to run complete_jobs after io_jobs and before + * unplug because the block device could be destroyed in + * job completion callback. */ process_jobs(&kc->complete_jobs, kc, run_complete_job); process_jobs(&kc->pages_jobs, kc, run_pages_job); process_jobs(&kc->io_jobs, kc, run_io_job); + unplug(kc, READ); + unplug(kc, WRITE); } /* @@ -619,6 +665,8 @@ int dm_kcopyd_client_create(unsigned int nr_pages, INIT_LIST_HEAD(&kc->io_jobs); INIT_LIST_HEAD(&kc->pages_jobs); + memset(kc->unplug, 0, sizeof(kc->unplug)); + kc->job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache); if (!kc->job_pool) goto bad_slab; |