block: remove per-queue plugging

[mirror_ubuntu-artful-kernel.git] / fs / btrfs / volumes.c

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index af7dbca1527629417ed14a67aff93fc86fe4d8a9..6e0e82a1b188aa4b8f24d4770b91261816e1065f 100644 (file)
--- 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;