Re: [PATCH 1/4] USB: usbfs: replace __get_free_page() with kmalloc()

[Mike Rapoport]

On Mon, Aug 31, 2026 at 03:27:07PM +0200, Oliver Neukum wrote:
> On 30.08.26 10:10, Mike Rapoport (Microsoft) wrote:
> > do_proc_control() allocates a temporary buffer for the data stage of a
> > control transfer issued from userspace.
> > 
> > This buffer can be allocated with kmalloc() as there's nothing special
> > about it to go directly to the page allocator.
> 
> You are breaking the calculation. A page has a size of exactly
> PAGE_SIZE. A kmalloced object of PAGE_SIZE is larger. That is
> a bad idea.

What calculation does it break and why do you say that kmalloc(PAGE_SIZE)
gives you an object larger than PAGE_SIZE?
 
> 	Regards
> 		Oliver
> 

-- 
Sincerely yours,
Mike.