Fix more "deprecated" spellos.

[powerpc.git] / Documentation / CodingStyle

diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle
index 0ad6dcb..afc2867 100644 (file)
--- a/Documentation/CodingStyle
+++ b/Documentation/CodingStyle
@@ -160,6 +160,21 @@ supply of new-lines on your screen is not a renewable resource (think
 25-line terminal screens here), you have more empty lines to put
 comments on.
 
+Do not unnecessarily use braces where a single statement will do.
+
+if (condition)
+       action();
+
+This does not apply if one branch of a conditional statement is a single
+statement. Use braces in both branches.
+
+if (condition) {
+       do_this();
+       do_that();
+} else {
+       otherwise();
+}
+
                3.1:  Spaces
 
 Linux kernel style for use of spaces depends (mostly) on
@@ -625,7 +640,7 @@ language.
 
 There appears to be a common misperception that gcc has a magic "make me
 faster" speedup option called "inline". While the use of inlines can be
-appropriate (for example as a means of replacing macros, see Chapter 11), it
+appropriate (for example as a means of replacing macros, see Chapter 12), it
 very often is not. Abundant use of the inline keyword leads to a much bigger
 kernel, which in turn slows the system as a whole down, due to a bigger
 icache footprint for the CPU and simply because there is less memory
@@ -682,6 +697,24 @@ result.  Typical examples would be functions that return pointers; they use
 NULL or the ERR_PTR mechanism to report failure.
 
 
+               Chapter 17:  Don't re-invent the kernel macros
+
+The header file include/linux/kernel.h contains a number of macros that
+you should use, rather than explicitly coding some variant of them yourself.
+For example, if you need to calculate the length of an array, take advantage
+of the macro
+
+  #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+Similarly, if you need to calculate the size of some structure member, use
+
+  #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
+
+There are also min() and max() macros that do strict type checking if you
+need them.  Feel free to peruse that header file to see what else is already
+defined that you shouldn't reproduce in your code.
+
+
 
                Appendix I: References