[PATCH] CodingStyle: memory allocation

This patch adds a new chapter on memory allocation to
Documentation/CodingStyle.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle
index 22e5f9036f3c193f88d14611b2e5fe669b2c9b9e..eb7db3c192273aa7b7b5d9244593c4add69bc863 100644 (file)
--- a/Documentation/CodingStyle
+++ b/Documentation/CodingStyle
@@ -410,7 +410,26 @@ Kernel messages do not have to be terminated with a period.
 Printing numbers in parentheses (%d) adds no value and should be avoided.
 
 
-               Chapter 13: References
+               Chapter 13: Allocating memory
+
+The kernel provides the following general purpose memory allocators:
+kmalloc(), kzalloc(), kcalloc(), and vmalloc().  Please refer to the API
+documentation for further information about them.
+
+The preferred form for passing a size of a struct is the following:
+
+       p = kmalloc(sizeof(*p), ...);
+
+The alternative form where struct name is spelled out hurts readability and
+introduces an opportunity for a bug when the pointer variable type is changed
+but the corresponding sizeof that is passed to a memory allocator is not.
+
+Casting the return value which is a void pointer is redundant. The conversion
+from void pointer to any other pointer type is guaranteed by the C programming
+language.
+
+
+               Chapter 14: References
 
 The C Programming Language, Second Edition
 by Brian W. Kernighan and Dennis M. Ritchie.