Re: [PATCH] x86/microcode/intel: Fix allocation size of struct ucode_patch

From: Borislav Petkov
Date: Thu Jan 05 2017 - 19:03:00 EST


On Thu, Jan 05, 2017 at 11:52:07PM +0000, Junichi Nomura wrote:
> >> + p = kzalloc(sizeof(struct ucode_patch), GFP_KERNEL);
> >
> > Perhaps sizeof(*p) ?
>
> Yeah, that might be preferred.

No, those things are never preferred because

sizeof(struct <type>)

tells you exactly the size of what kind of object you're getting vs

sizeof(*p)

which tells you you're getting the size of what p points to.

Now you have to go look at p and what type it is. In the current case, p
is defined not far away from the use site but in a larger function, you
most likely need to eyeball up to its type when reading the code. Which
makes the whole thing less readable.

--
Regards/Gruss,
Boris.

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