block: remove per-queue plugging

Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 5 insertions, 47 deletions

diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 924f5f0084c2..400cf35094a4 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -37,13 +37,6 @@ 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;
@@ -315,31 +308,6 @@ 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;
@@ -386,15 +354,12 @@ 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);
-                prepare_unplug(job->kc, READ, job->source.bdev);
-        } else {
+        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;
@@ -466,6 +431,7 @@ static void do_work(struct work_struct *work)
 {
         struct dm_kcopyd_client *kc = container_of(work,
                                         struct dm_kcopyd_client, kcopyd_work);
+        struct blk_plug plug;
 
         /*
          * The order that these are called is *very* important.
@@ -473,18 +439,12 @@ 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.
          */
+        blk_start_plug(&plug);
         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);
+        blk_finish_plug(&plug);
 }
 
 /*
@@ -665,8 +625,6 @@ 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;