docs/core-api/mm: fix return value descriptions in mm/

Many kernel-doc comments in mm/ have the return value descriptions
either misformatted or omitted at all which makes kernel-doc script
unhappy:

$ make V=1 htmldocs
...
./mm/util.c:36: info: Scanning doc for kstrdup
./mm/util.c:41: warning: No description found for return value of 'kstrdup'
./mm/util.c:57: info: Scanning doc for kstrdup_const
./mm/util.c:66: warning: No description found for return value of 'kstrdup_const'
./mm/util.c:75: info: Scanning doc for kstrndup
./mm/util.c:83: warning: No description found for return value of 'kstrndup'
...

Fixing the formatting and adding the missing return value descriptions
eliminates ~100 such warnings.

Link: http://lkml.kernel.org/r/1549549644-4903-4-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 7510a1b489df..28652e4218e0 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1727,6 +1727,8 @@ static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list)
  * This could be made much more intelligent.  For now, try to avoid using
  * high order pages for slabs.  When the gfp() functions are more friendly
  * towards high-order requests, this should be changed.
+ *
+ * Return: number of left-over bytes in a slab
  */
 static size_t calculate_slab_order(struct kmem_cache *cachep,
 				size_t size, slab_flags_t flags)
@@ -1975,6 +1977,8 @@ static bool set_on_slab_cache(struct kmem_cache *cachep,
  * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
  * cacheline.  This can be beneficial if you're counting cycles as closely
  * as davem.
+ *
+ * Return: a pointer to the created cache or %NULL in case of error
  */
 int __kmem_cache_create(struct kmem_cache *cachep, slab_flags_t flags)
 {
@@ -3542,6 +3546,8 @@ void ___cache_free(struct kmem_cache *cachep, void *objp,
  *
  * Allocate an object from this cache.  The flags are only relevant
  * if the cache has no available objects.
+ *
+ * Return: pointer to the new object or %NULL in case of error
  */
 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
 {
@@ -3631,6 +3637,8 @@ EXPORT_SYMBOL(kmem_cache_alloc_trace);
  * node, which can improve the performance for cpu bound structures.
  *
  * Fallback to other node is possible if __GFP_THISNODE is not set.
+ *
+ * Return: pointer to the new object or %NULL in case of error
  */
 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
 {
@@ -3699,6 +3707,8 @@ EXPORT_SYMBOL(__kmalloc_node_track_caller);
  * @size: how many bytes of memory are required.
  * @flags: the type of memory to allocate (see kmalloc).
  * @caller: function caller for debug tracking of the caller
+ *
+ * Return: pointer to the allocated memory or %NULL in case of error
  */
 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
 					  unsigned long caller)
@@ -4164,6 +4174,8 @@ void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
  * @buffer: user buffer
  * @count: data length
  * @ppos: unused
+ *
+ * Return: %0 on success, negative error code otherwise.
  */
 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 		       size_t count, loff_t *ppos)
@@ -4457,6 +4469,8 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
  * The caller must guarantee that objp points to a valid object previously
  * allocated with either kmalloc() or kmem_cache_alloc(). The object
  * must not be freed during the duration of the call.
+ *
+ * Return: size of the actual memory used by @objp in bytes
  */
 size_t ksize(const void *objp)
 {