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, 11 insertions, 80 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index af7dbca15276..6e0e82a1b188 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -162,7 +162,6 @@ static noinline int run_scheduled_bios(struct btrfs_device *device)
         struct bio *cur;
         int again = 0;
         unsigned long num_run;
-        unsigned long num_sync_run;
         unsigned long batch_run = 0;
         unsigned long limit;
         unsigned long last_waited = 0;
@@ -173,11 +172,6 @@ static noinline int run_scheduled_bios(struct btrfs_device *device)
         limit = btrfs_async_submit_limit(fs_info);
         limit = limit * 2 / 3;
 
-        /* we want to make sure that every time we switch from the sync
-         * list to the normal list, we unplug
-         */
-        num_sync_run = 0;
-
 loop:
         spin_lock(&device->io_lock);
 
@@ -223,15 +217,6 @@ loop_lock:
 
         spin_unlock(&device->io_lock);
 
-        /*
-         * if we're doing the regular priority list, make sure we unplug
-         * for any high prio bios we've sent down
-         */
-        if (pending_bios == &device->pending_bios && num_sync_run > 0) {
-                num_sync_run = 0;
-                blk_run_backing_dev(bdi, NULL);
-        }
-
         while (pending) {
 
                 rmb();
@@ -259,19 +244,11 @@ loop_lock:
 
                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 
-                if (cur->bi_rw & REQ_SYNC)
-                        num_sync_run++;
-
                 submit_bio(cur->bi_rw, cur);
                 num_run++;
                 batch_run++;
-                if (need_resched()) {
-                        if (num_sync_run) {
-                                blk_run_backing_dev(bdi, NULL);
-                                num_sync_run = 0;
-                        }
+                if (need_resched())
                         cond_resched();
-                }
 
                 /*
                  * we made progress, there is more work to do and the bdi
@@ -304,13 +281,8 @@ loop_lock:
                                  * against it before looping
                                  */
                                 last_waited = ioc->last_waited;
-                                if (need_resched()) {
-                                        if (num_sync_run) {
-                                                blk_run_backing_dev(bdi, NULL);
-                                                num_sync_run = 0;
-                                        }
+                                if (need_resched())
                                         cond_resched();
-                                }
                                 continue;
                         }
                         spin_lock(&device->io_lock);
@@ -323,22 +295,6 @@ loop_lock:
                 }
         }
 
-        if (num_sync_run) {
-                num_sync_run = 0;
-                blk_run_backing_dev(bdi, NULL);
-        }
-        /*
-         * IO has already been through a long path to get here.  Checksumming,
-         * async helper threads, perhaps compression.  We've done a pretty
-         * good job of collecting a batch of IO and should just unplug
-         * the device right away.
-         *
-         * This will help anyone who is waiting on the IO, they might have
-         * already unplugged, but managed to do so before the bio they
-         * cared about found its way down here.
-         */
-        blk_run_backing_dev(bdi, NULL);
-
         cond_resched();
         if (again)
                 goto loop;
@@ -2948,7 +2904,7 @@ static int find_live_mirror(struct map_lookup *map, int first, int num,
 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                              u64 logical, u64 *length,
                              struct btrfs_multi_bio **multi_ret,
-                             int mirror_num, struct page *unplug_page)
+                             int mirror_num)
 {
         struct extent_map *em;
         struct map_lookup *map;
@@ -2980,11 +2936,6 @@ again:
         em = lookup_extent_mapping(em_tree, logical, *length);
         read_unlock(&em_tree->lock);
 
-        if (!em && unplug_page) {
-                kfree(multi);
-                return 0;
-        }
-
         if (!em) {
                 printk(KERN_CRIT "unable to find logical %llu len %llu\n",
                        (unsigned long long)logical,
@@ -3040,13 +2991,13 @@ again:
                 *length = em->len - offset;
         }
 
-        if (!multi_ret && !unplug_page)
+        if (!multi_ret)
                 goto out;
 
         num_stripes = 1;
         stripe_index = 0;
         if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
-                if (unplug_page || (rw & REQ_WRITE))
+                if (rw & REQ_WRITE)
                         num_stripes = map->num_stripes;
                 else if (mirror_num)
                         stripe_index = mirror_num - 1;
@@ -3068,7 +3019,7 @@ again:
                 stripe_index = do_div(stripe_nr, factor);
                 stripe_index *= map->sub_stripes;
 
-                if (unplug_page || (rw & REQ_WRITE))
+                if (rw & REQ_WRITE)
                         num_stripes = map->sub_stripes;
                 else if (mirror_num)
                         stripe_index += mirror_num - 1;
@@ -3088,22 +3039,10 @@ again:
         BUG_ON(stripe_index >= map->num_stripes);
 
         for (i = 0; i < num_stripes; i++) {
-                if (unplug_page) {
-                        struct btrfs_device *device;
-                        struct backing_dev_info *bdi;
-
-                        device = map->stripes[stripe_index].dev;
-                        if (device->bdev) {
-                                bdi = blk_get_backing_dev_info(device->bdev);
-                                if (bdi->unplug_io_fn)
-                                        bdi->unplug_io_fn(bdi, unplug_page);
-                        }
-                } else {
-                        multi->stripes[i].physical =
-                                map->stripes[stripe_index].physical +
-                                stripe_offset + stripe_nr * map->stripe_len;
-                        multi->stripes[i].dev = map->stripes[stripe_index].dev;
-                }
+                multi->stripes[i].physical =
+                        map->stripes[stripe_index].physical +
+                        stripe_offset + stripe_nr * map->stripe_len;
+                multi->stripes[i].dev = map->stripes[stripe_index].dev;
                 stripe_index++;
         }
         if (multi_ret) {
@@ -3121,7 +3060,7 @@ int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                       struct btrfs_multi_bio **multi_ret, int mirror_num)
 {
         return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
-                                 mirror_num, NULL);
+                                 mirror_num);
 }
 
 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
@@ -3189,14 +3128,6 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
         return 0;
 }
 
-int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
-                      u64 logical, struct page *page)
-{
-        u64 length = PAGE_CACHE_SIZE;
-        return __btrfs_map_block(map_tree, READ, logical, &length,
-                                 NULL, 0, page);
-}
-
 static void end_bio_multi_stripe(struct bio *bio, int err)
 {
         struct btrfs_multi_bio *multi = bio->bi_private;