[PATCH] Document kfree and vfree NULL usage

[Pekka Enberg <penberg@cs.helsinki.fi>]

Hi,

This patch adds comments for kfree() and vfree() stating that both accept
NULL pointers.  I audited vfree() callers and there seems to be lots of
confusion over this in the kernel.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---

 slab.c    |    2 ++
 vmalloc.c |    3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

Index: 2.6.10-rc2/mm/slab.c
===================================================================
--- 2.6.10-rc2.orig/mm/slab.c	2004-11-27 14:33:14.000000000 +0200
+++ 2.6.10-rc2/mm/slab.c	2004-11-27 16:12:54.573387384 +0200
@@ -2535,6 +2535,8 @@
  * 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.
  */
Index: 2.6.10-rc2/mm/vmalloc.c
===================================================================
--- 2.6.10-rc2.orig/mm/vmalloc.c	2004-11-27 16:13:48.026261312 +0200
+++ 2.6.10-rc2/mm/vmalloc.c	2004-11-27 16:14:04.875699808 +0200
@@ -389,7 +389,8 @@
  *	@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.
  */