From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Joe Perches <joe@perches.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
"Bartosz Golaszewski" <brgl@bgdev.pl>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Gustavo Padovan" <gustavo@padovan.org>,
"Christian König" <christian.koenig@amd.com>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>,
"Borislav Petkov" <bp@alien8.de>,
"Tony Luck" <tony.luck@intel.com>,
"James Morse" <james.morse@arm.com>,
"Robert Richter" <rric@kernel.org>,
"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
"Maxime Ripard" <mripard@kernel.org>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"David Airlie" <airlied@linux.ie>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
"Linus Walleij" <linus.walleij@linaro.org>,
"Jason Wang" <jasowang@redhat.com>,
"Christoph Lameter" <cl@linux.com>,
"Pekka Enberg" <penberg@kernel.org>,
"David Rientjes" <rientjes@google.com>,
"Joonsoo Kim" <iamjoonsoo.kim@lge.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Jaroslav Kysela" <perex@perex.cz>,
"Takashi Iwai" <tiwai@suse.com>,
linux-media <linux-media@vger.kernel.org>,
linux-drm <dri-devel@lists.freedesktop.org>,
linaro-mm-sig@lists.linaro.org,
LKML <linux-kernel@vger.kernel.org>,
linux-edac@vger.kernel.org,
linux-gpio <linux-gpio@vger.kernel.org>,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
netdev <netdev@vger.kernel.org>,
linux-mm@kvack.org, Linux-ALSA <alsa-devel@alsa-project.org>
Subject: Re: [PATCH 3/8] vhost: vringh: use krealloc_array()
Date: Tue, 27 Oct 2020 17:58:43 +0100 [thread overview]
Message-ID: <CAMpxmJU0C84DjPmqmWvPgv0zwgGLhkpKLRDuKkZHAa=wi+LvBA@mail.gmail.com> (raw)
In-Reply-To: <685d850347a1191bba8ba7766fc409b140d18f03.camel@perches.com>
On Tue, Oct 27, 2020 at 5:50 PM Joe Perches <joe@perches.com> wrote:
>
> On Tue, 2020-10-27 at 11:28 -0400, Michael S. Tsirkin wrote:
> > On Tue, Oct 27, 2020 at 01:17:20PM +0100, Bartosz Golaszewski wrote:
> > > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > >
> > > Use the helper that checks for overflows internally instead of manually
> > > calculating the size of the new array.
> > >
> > > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> >
> > No problem with the patch, it does introduce some symmetry in the code.
>
> Perhaps more symmetry by using kmemdup
> ---
> drivers/vhost/vringh.c | 23 ++++++++++-------------
> 1 file changed, 10 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> index 8bd8b403f087..99222a3651cd 100644
> --- a/drivers/vhost/vringh.c
> +++ b/drivers/vhost/vringh.c
> @@ -191,26 +191,23 @@ static int move_to_indirect(const struct vringh *vrh,
> static int resize_iovec(struct vringh_kiov *iov, gfp_t gfp)
> {
> struct kvec *new;
> - unsigned int flag, new_num = (iov->max_num & ~VRINGH_IOV_ALLOCATED) * 2;
> + size_t new_num = (iov->max_num & ~VRINGH_IOV_ALLOCATED) * 2;
> + size_t size;
>
> if (new_num < 8)
> new_num = 8;
>
> - flag = (iov->max_num & VRINGH_IOV_ALLOCATED);
> - if (flag)
> - new = krealloc(iov->iov, new_num * sizeof(struct iovec), gfp);
> - else {
> - new = kmalloc_array(new_num, sizeof(struct iovec), gfp);
> - if (new) {
> - memcpy(new, iov->iov,
> - iov->max_num * sizeof(struct iovec));
> - flag = VRINGH_IOV_ALLOCATED;
> - }
> - }
> + if (unlikely(check_mul_overflow(new_num, sizeof(struct iovec), &size)))
> + return -ENOMEM;
> +
The whole point of using helpers such as kmalloc_array() is not doing
these checks manually.
Bartosz
> + if (iov->max_num & VRINGH_IOV_ALLOCATED)
> + new = krealloc(iov->iov, size, gfp);
> + else
> + new = kmemdup(iov->iov, size, gfp);
> if (!new)
> return -ENOMEM;
> iov->iov = new;
> - iov->max_num = (new_num | flag);
> + iov->max_num = new_num | VRINGH_IOV_ALLOCATED;
> return 0;
> }
>
>
>
next prev parent reply other threads:[~2020-10-27 16:59 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 12:17 [PATCH 0/8] slab: provide and use krealloc_array() Bartosz Golaszewski
2020-10-27 12:17 ` [PATCH 1/8] mm: slab: provide krealloc_array() Bartosz Golaszewski
2020-10-27 18:20 ` Vlastimil Babka
2020-10-28 8:47 ` Mike Rapoport
2020-10-27 12:17 ` [PATCH 2/8] ALSA: pcm: use krealloc_array() Bartosz Golaszewski
2020-10-27 12:39 ` Takashi Iwai
2020-10-27 12:17 ` [PATCH 3/8] vhost: vringh: " Bartosz Golaszewski
2020-10-27 15:28 ` Michael S. Tsirkin
2020-10-27 16:50 ` Joe Perches
2020-10-27 16:58 ` Bartosz Golaszewski [this message]
2020-10-27 17:08 ` Joe Perches
2020-10-27 18:00 ` Bartosz Golaszewski
2020-10-27 12:17 ` [PATCH 4/8] pinctrl: " Bartosz Golaszewski
2020-10-27 12:17 ` [PATCH 5/8] edac: ghes: " Bartosz Golaszewski
2020-10-27 18:25 ` Borislav Petkov
2020-10-27 12:17 ` [PATCH 6/8] drm: atomic: " Bartosz Golaszewski
2020-10-27 19:19 ` Daniel Vetter
2020-10-27 12:17 ` [PATCH 7/8] hwtracing: intel: " Bartosz Golaszewski
2020-10-27 12:17 ` [PATCH 8/8] dma-buf: " Bartosz Golaszewski
2020-10-27 12:21 ` Christian König
2020-11-05 10:52 ` [PATCH 0/8] slab: provide and " Linus Walleij
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