[PATCH] update kfree, vfree, and vunmap kerneldoc

This patch clarifies NULL handling of kfree() and vfree().  I addition,
wording of calling context restriction for vfree() and vunmap() are changed
from "may not" to "must not."

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 6 insertions, 3 deletions

diff --git a/mm/slab.c b/mm/slab.c
index a041c5378dfa..05a391059fe1 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2998,6 +2998,8 @@ EXPORT_SYMBOL(kzalloc);
  * kfree - free previously allocated memory
  * @objp: pointer returned by kmalloc.
  *
+ * If @objp is NULL, no operation is performed.
+ *
  * Don't free memory not originally allocated by kmalloc()
  * or you will run into trouble.
  */
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 67b358e57ef6..13c3d82968ae 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -332,9 +332,10 @@ void __vunmap(void *addr, int deallocate_pages)
  *      @addr:          memory base address
  *
  *      Free the virtually contiguous memory area starting at @addr, as
- *      obtained from vmalloc(), vmalloc_32() or __vmalloc().
+ *      obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
+ *      NULL, no operation is performed.
  *
- *      May not be called in interrupt context.
+ *      Must not be called in interrupt context.
  */
 void vfree(void *addr)
 {
@@ -352,7 +353,7 @@ EXPORT_SYMBOL(vfree);
  *      Free the virtually contiguous memory area starting at @addr,
  *      which was created from the page array passed to vmap().
  *
- *      May not be called in interrupt context.
+ *      Must not be called in interrupt context.
  */
 void vunmap(void *addr)
 {