btrfs: merge ordered work callbacks in btrfs_work into one

There are two callbacks defined in btrfs_work but only two actually make
use of them, otherwise there are NULLs. We can get rid of the freeing
callback making it a special case of the normal work. This reduces the
size of btrfs_work by 8 bytes, final layout:

struct btrfs_work {
        btrfs_func_t               func;                 /*     0     8 */
        btrfs_ordered_func_t       ordered_func;         /*     8     8 */
        struct work_struct         normal_work;          /*    16    32 */
        struct list_head           ordered_list;         /*    48    16 */
        /* --- cacheline 1 boundary (64 bytes) --- */
        struct btrfs_workqueue *   wq;                   /*    64     8 */
        long unsigned int          flags;                /*    72     8 */

        /* size: 80, cachelines: 2, members: 6 */
        /* last cacheline: 16 bytes */
};

This in turn reduces size of other structures (on a release config):

- async_chunk			 160 ->  152
- async_submit_bio		 152 ->  144
- btrfs_async_delayed_work	 104 ->   96
- btrfs_caching_control		 176 ->  168
- btrfs_delalloc_work		 144 ->  136
- btrfs_fs_info			3608 -> 3600
- btrfs_ordered_extent		 440 ->  424
- btrfs_writepage_fixup		 104 ->   96

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 5 insertions, 6 deletions

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 714ca74b66bf..9e261aac671e 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -243,7 +243,7 @@ static void run_ordered_work(struct btrfs_workqueue *wq,
 			break;
 		trace_btrfs_ordered_sched(work);
 		spin_unlock_irqrestore(lock, flags);
-		work->ordered_func(work);
+		work->ordered_func(work, false);
 
 		/* now take the lock again and drop our item from the list */
 		spin_lock_irqsave(lock, flags);
@@ -278,7 +278,7 @@ static void run_ordered_work(struct btrfs_workqueue *wq,
 			 * We don't want to call the ordered free functions with
 			 * the lock held.
 			 */
-			work->ordered_free(work);
+			work->ordered_func(work, true);
 			/* NB: work must not be dereferenced past this point. */
 			trace_btrfs_all_work_done(wq->fs_info, work);
 		}
@@ -286,7 +286,7 @@ static void run_ordered_work(struct btrfs_workqueue *wq,
 	spin_unlock_irqrestore(lock, flags);
 
 	if (free_self) {
-		self->ordered_free(self);
+		self->ordered_func(self, true);
 		/* NB: self must not be dereferenced past this point. */
 		trace_btrfs_all_work_done(wq->fs_info, self);
 	}
@@ -301,7 +301,7 @@ static void btrfs_work_helper(struct work_struct *normal_work)
 
 	/*
 	 * We should not touch things inside work in the following cases:
-	 * 1) after work->func() if it has no ordered_free
+	 * 1) after work->func() if it has no ordered_func(..., true) to free
 	 *    Since the struct is freed in work->func().
 	 * 2) after setting WORK_DONE_BIT
 	 *    The work may be freed in other threads almost instantly.
@@ -330,11 +330,10 @@ static void btrfs_work_helper(struct work_struct *normal_work)
 }
 
 void btrfs_init_work(struct btrfs_work *work, btrfs_func_t func,
-		     btrfs_func_t ordered_func, btrfs_func_t ordered_free)
+		     btrfs_ordered_func_t ordered_func)
 {
 	work->func = func;
 	work->ordered_func = ordered_func;
-	work->ordered_free = ordered_free;
 	INIT_WORK(&work->normal_work, btrfs_work_helper);
 	INIT_LIST_HEAD(&work->ordered_list);
 	work->flags = 0;