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btrfs: use assertion helpers for spinning writers 

Use the helpers where open coded. On non-debug builds, the warnings will
not trigger and extent_buffer::spining_writers become unused and can be
moved to the appropriate section, saving a few bytes.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2018-08-24 14:56:28 +02:00
parent e4e9fd0f32
commit 843ccf9f46
3 changed files with 11 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
fs/btrfs/extent_io.c
View File

@ -4682,7 +4682,6 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
atomic_set(&eb->blocking_readers, 0);
atomic_set(&eb->blocking_writers, 0);
atomic_set(&eb->spinning_readers, 0);
atomic_set(&eb->spinning_writers, 0);
eb->lock_nested = 0;
init_waitqueue_head(&eb->write_lock_wq);
init_waitqueue_head(&eb->read_lock_wq);
@ -4700,6 +4699,10 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
> MAX_INLINE_EXTENT_BUFFER_SIZE);
BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
#ifdef CONFIG_BTRFS_DEBUG
atomic_set(&eb->spinning_writers, 0);
#endif
return eb;
}

2
fs/btrfs/extent_io.h
View File

@ -166,7 +166,6 @@ struct extent_buffer {
atomic_t blocking_writers;
atomic_t blocking_readers;
atomic_t spinning_readers;
atomic_t spinning_writers;
short lock_nested;
/* >= 0 if eb belongs to a log tree, -1 otherwise */
short log_index;
@ -185,6 +184,7 @@ struct extent_buffer {
wait_queue_head_t read_lock_wq;
struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
#ifdef CONFIG_BTRFS_DEBUG
atomic_t spinning_writers;
struct list_head leak_list;
#endif
};

16
fs/btrfs/locking.c
View File

@ -64,8 +64,7 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
if (eb->lock_nested && current->pid == eb->lock_owner)
return;
if (atomic_read(&eb->blocking_writers) == 0) {
WARN_ON(atomic_read(&eb->spinning_writers) != 1);
atomic_dec(&eb->spinning_writers);
btrfs_assert_spinning_writers_put(eb);
btrfs_assert_tree_locked(eb);
atomic_inc(&eb->blocking_writers);
write_unlock(&eb->lock);
@ -101,8 +100,7 @@ void btrfs_clear_lock_blocking_write(struct extent_buffer *eb)
return;
BUG_ON(atomic_read(&eb->blocking_writers) != 1);
write_lock(&eb->lock);
WARN_ON(atomic_read(&eb->spinning_writers));
atomic_inc(&eb->spinning_writers);
btrfs_assert_spinning_writers_get(eb);
/* atomic_dec_and_test implies a barrier */
if (atomic_dec_and_test(&eb->blocking_writers))
cond_wake_up_nomb(&eb->write_lock_wq);
@ -200,7 +198,7 @@ int btrfs_try_tree_write_lock(struct extent_buffer *eb)
return 0;
}
atomic_inc(&eb->write_locks);
atomic_inc(&eb->spinning_writers);
btrfs_assert_spinning_writers_get(eb);
eb->lock_owner = current->pid;
return 1;
}
@ -266,8 +264,7 @@ again:
write_unlock(&eb->lock);
goto again;
}
WARN_ON(atomic_read(&eb->spinning_writers));
atomic_inc(&eb->spinning_writers);
btrfs_assert_spinning_writers_get(eb);
atomic_inc(&eb->write_locks);
eb->lock_owner = current->pid;
}
@ -286,14 +283,13 @@ void btrfs_tree_unlock(struct extent_buffer *eb)
atomic_dec(&eb->write_locks);
if (blockers) {
WARN_ON(atomic_read(&eb->spinning_writers));
btrfs_assert_no_spinning_writers(eb);
atomic_dec(&eb->blocking_writers);
/* Use the lighter barrier after atomic */
smp_mb__after_atomic();
cond_wake_up_nomb(&eb->write_lock_wq);
} else {
WARN_ON(atomic_read(&eb->spinning_writers) != 1);
atomic_dec(&eb->spinning_writers);
btrfs_assert_spinning_writers_put(eb);
write_unlock(&eb->lock);
}
}