Re: kfree(NULL)

[linux@horizon.com]

> Well, we'd have to start by fixing up the janitors that run around
> taking out the if statements in the callers.  :)

You just need to document those two as special.  Probably the
simplest is to tell the programmer and the compiler in one
fell swoop:

	if (unlikely(p))
		kfree(p);

Or that could be wrapped up in a macro:

#define kfree_likely_null(p) if (unlikely(p)) kfree(p)

Or just mention it to the programmer.  A few possible one-line comments:

	/* Testing before calling is faster if often NULL, as here. */
	/* It's worth the (redundant) test for NULL if it often succeeds */
	/* This test saves the call often enough to be worth it. */
	/* Test for NULL not necessary, but worth it here */
	/* Don't delete NULL test; speed trumps code size here */
	/* Very often NULL, so avoid call overhead if possible */
	/* kfree(NULL) is legal, but probabilities favor testing here */