From: Mike Rapoport <rppt@kernel.org>
To: Oliver Neukum <oneukum@suse.com>
Cc: Chas Williams <3chas3@gmail.com>,
Duncan Sands <duncan.sands@free.fr>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Johan Hovold <johan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
accessrunner-general@lists.sourceforge.net,
linux-atm-general@lists.sourceforge.net,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-usb@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 1/4] USB: usbfs: replace __get_free_page() with kmalloc()
Date: Mon, 31 Aug 2026 17:24:50 +0300 [thread overview]
Message-ID: <apWOslh5BF-ISQ6f@kernel.org> (raw)
In-Reply-To: <ea165ff8-cda2-4fed-9354-1d14ac2d87ca@suse.com>
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.
next prev parent reply other threads:[~2026-08-31 14:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-30 8:10 [PATCH 0/4] USB: replace page allocator calls with kmalloc() Mike Rapoport (Microsoft)
2026-08-30 8:10 ` [PATCH 1/4] USB: usbfs: replace __get_free_page() " Mike Rapoport (Microsoft)
2026-08-31 13:27 ` Oliver Neukum
2026-08-31 14:24 ` Mike Rapoport [this message]
2026-08-31 14:30 ` Alan Stern
2026-09-02 14:36 ` Vlastimil Babka (SUSE)
2026-08-30 8:10 ` [PATCH 2/4] USB: cxacru: " Mike Rapoport (Microsoft)
2026-08-30 8:10 ` [PATCH 3/4] USB: speedtch: " Mike Rapoport (Microsoft)
2026-08-30 8:10 ` [PATCH 4/4] USB: serial: wwan: " Mike Rapoport (Microsoft)
2026-09-03 2:00 ` [PATCH 0/4] USB: replace page allocator calls " patchwork-bot+netdevbpf
2026-09-03 6:20 ` Johan Hovold
2026-09-03 10:54 ` Johan Hovold
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