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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>
This commit is contained in:
Christoph Hellwig 2008-06-11 21:52:17 -04:00 committed by Chris Mason
parent 4543df7ecc
commit 9d2423c5c3
1 changed files with 49 additions and 12 deletions
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61
fs/btrfs/extent_map.c
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@ -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)
{