Re: p = kmalloc(sizeof(*p), )

From: Alan Cox
Date: Sun Sep 18 2005 - 05:39:19 EST


On Sul, 2005-09-18 at 11:06 +0100, Russell King wrote:
> I completely disagree with the above assertion for the following
> reasons:

Ditto, but you forgot #4. People are always getting sizeof(*p) wrong, in
particular forgetting that p happens to be a void *, or a struct that is
some generic type not the full space for the more complex object
allocated, so using (*p) everywhere just causes more memory scribbles.

If it bugs people add a kmalloc_object macro that is

#define new_object(foo, gfp) (foo *)kmalloc(sizeof(foo), (gfp))

then you can

x = new_object(struct frob, GFP_KERNEL)

Other good practice in many cases is a single routine which allocates
and initialises the structure and is used by all allocators of that
object. That removes duplicate initialisers, stops people forgetting to
update all cases, allows better debug and far more.

Alan

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/