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authorChristoph Hellwig <hch@lst.de>2008-06-11 21:52:17 -0400
committerChris Mason <chris.mason@oracle.com>2008-09-25 11:04:03 -0400
commit9d2423c5c3fbb0f110ac0b6cdc5a8e4d64729483 (patch)
tree99060a576abf496365969bd1272d6905d0d5bded /fs/btrfs/extent_map.c
parent4543df7ecc8ae4928c1e51d6e7dc188d650abee4 (diff)
Btrfs: kerneldoc comments for extent_map.c
Add kerneldoc comments for all exported functions. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/extent_map.c')
-rw-r--r--fs/btrfs/extent_map.c61
1 files changed, 49 insertions, 12 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index ba46f7911d9..f5a04eb9a2a 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -31,6 +31,14 @@ void extent_map_exit(void)
kmem_cache_destroy(extent_map_cache);
}
+/**
+ * extent_map_tree_init - initialize extent map tree
+ * @tree: tree to initialize
+ * @mask: flags for memory allocations during tree operations
+ *
+ * Initialize the extent tree @tree. Should be called for each new inode
+ * or other user of the extent_map interface.
+ */
void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask)
{
tree->map.rb_node = NULL;
@@ -39,6 +47,14 @@ void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask)
}
EXPORT_SYMBOL(extent_map_tree_init);
+/**
+ * alloc_extent_map - allocate new extent map structure
+ * @mask: memory allocation flags
+ *
+ * Allocate a new extent_map structure. The new structure is
+ * returned with a reference count of one and needs to be
+ * freed using free_extent_map()
+ */
struct extent_map *alloc_extent_map(gfp_t mask)
{
struct extent_map *em;
@@ -52,6 +68,13 @@ struct extent_map *alloc_extent_map(gfp_t mask)
}
EXPORT_SYMBOL(alloc_extent_map);
+/**
+ * free_extent_map - drop reference count of an extent_map
+ * @em: extent map beeing releasead
+ *
+ * Drops the reference out on @em by one and free the structure
+ * if the reference count hits zero.
+ */
void free_extent_map(struct extent_map *em)
{
if (!em)
@@ -166,10 +189,15 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next)
return 0;
}
-/*
- * add_extent_mapping tries a simple forward/backward merge with existing
- * mappings. The extent_map struct passed in will be inserted into
- * the tree directly (no copies made, just a reference taken).
+/**
+ * add_extent_mapping - add new extent map to the extent tree
+ * @tree: tree to insert new map in
+ * @em: map to insert
+ *
+ * Insert @em into @tree or perform a simple forward/backward merge with
+ * existing mappings. The extent_map struct passed in will be inserted
+ * into the tree directly, with an additional reference taken, or a
+ * reference dropped if the merge attempt was sucessfull.
*/
int add_extent_mapping(struct extent_map_tree *tree,
struct extent_map *em)
@@ -220,11 +248,16 @@ static u64 range_end(u64 start, u64 len)
return start + len;
}
-/*
- * lookup_extent_mapping returns the first extent_map struct in the
- * tree that intersects the [start, len] range. There may
- * be additional objects in the tree that intersect, so check the object
- * returned carefully to make sure you don't need additional lookups.
+/**
+ * lookup_extent_mapping - lookup extent_map
+ * @tree: tree to lookup in
+ * @start: byte offset to start the search
+ * @len: length of the lookup range
+ *
+ * Find and return the first extent_map struct in @tree that intersects the
+ * [start, len] range. There may be additional objects in the tree that
+ * intersect, so check the object returned carefully to make sure that no
+ * additional lookups are needed.
*/
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len)
@@ -273,9 +306,13 @@ out:
}
EXPORT_SYMBOL(lookup_extent_mapping);
-/*
- * removes an extent_map struct from the tree. No reference counts are
- * dropped, and no checks are done to see if the range is in use
+/**
+ * remove_extent_mapping - removes an extent_map from the extent tree
+ * @tree: extent tree to remove from
+ * @em: extent map beeing removed
+ *
+ * Removes @em from @tree. No reference counts are dropped, and no checks
+ * are done to see if the range is in use
*/
int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
{