diff options
| author | Jan Kara <jack@suse.cz> | 2021-05-24 13:02:30 +0200 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2021-07-13 14:29:00 +0200 |
| commit | 7506ae6a7033f617ca5fea53e356fb1f7bd98010 (patch) | |
| tree | 2f018aab5c218ed18d25d5c9521add9627010905 /mm | |
| parent | 730633f0b7f951726e87f912a6323641f674ae34 (diff) | |
mm: Add functions to lock invalidate_lock for two mappings
Some operations such as reflinking blocks among files will need to lock
invalidate_lock for two mappings. Add helper functions to do that.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index f7f9b87d2cd0..0fad08331cf4 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1010,6 +1010,44 @@ EXPORT_SYMBOL(__page_cache_alloc); #endif /* + * filemap_invalidate_lock_two - lock invalidate_lock for two mappings + * + * Lock exclusively invalidate_lock of any passed mapping that is not NULL. + * + * @mapping1: the first mapping to lock + * @mapping2: the second mapping to lock + */ +void filemap_invalidate_lock_two(struct address_space *mapping1, + struct address_space *mapping2) +{ + if (mapping1 > mapping2) + swap(mapping1, mapping2); + if (mapping1) + down_write(&mapping1->invalidate_lock); + if (mapping2 && mapping1 != mapping2) + down_write_nested(&mapping2->invalidate_lock, 1); +} +EXPORT_SYMBOL(filemap_invalidate_lock_two); + +/* + * filemap_invalidate_unlock_two - unlock invalidate_lock for two mappings + * + * Unlock exclusive invalidate_lock of any passed mapping that is not NULL. + * + * @mapping1: the first mapping to unlock + * @mapping2: the second mapping to unlock + */ +void filemap_invalidate_unlock_two(struct address_space *mapping1, + struct address_space *mapping2) +{ + if (mapping1) + up_write(&mapping1->invalidate_lock); + if (mapping2 && mapping1 != mapping2) + up_write(&mapping2->invalidate_lock); +} +EXPORT_SYMBOL(filemap_invalidate_unlock_two); + +/* * In order to wait for pages to become available there must be * waitqueues associated with pages. By using a hash table of * waitqueues where the bucket discipline is to maintain all |