linux-kernel - [PATCH v2 16/24] drm/i915/gvt: use vmalloc

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Message-Id: <20230627144339.144478-17-Julia.Lawall@inria.fr>
Date:   Tue, 27 Jun 2023 16:43:31 +0200
From:   Julia Lawall <Julia.Lawall@...ia.fr>
To:     Zhenyu Wang <zhenyuw@...ux.intel.com>
Cc:     kernel-janitors@...r.kernel.org, keescook@...omium.org,
        christophe.jaillet@...adoo.fr, kuba@...nel.org,
        Zhi Wang <zhi.a.wang@...el.com>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 16/24] drm/i915/gvt: use vmalloc_array and vcalloc

Use vmalloc_array and vcalloc to protect against
multiplication overflows.

The changes were done using the following Coccinelle
semantic patch:

// <smpl>
@initialize:ocaml@
@@

let rename alloc =
  match alloc with
    "vmalloc" -> "vmalloc_array"
  | "vzalloc" -> "vcalloc"
  | _ -> failwith "unknown"

@@
    size_t e1,e2;
    constant C1, C2;
    expression E1, E2, COUNT, x1, x2, x3;
    typedef u8;
    typedef __u8;
    type t = {u8,__u8,char,unsigned char};
    identifier alloc = {vmalloc,vzalloc};
    fresh identifier realloc = script:ocaml(alloc) { rename alloc };
@@

(
      alloc(x1*x2*x3)
|
      alloc(C1 * C2)
|
      alloc((sizeof(t)) * (COUNT), ...)
|
-     alloc((e1) * (e2))
+     realloc(e1, e2)
|
-     alloc((e1) * (COUNT))
+     realloc(COUNT, e1)
|
-     alloc((E1) * (E2))
+     realloc(E1, E2)
)
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@...ia.fr>

---
v2: Use vmalloc_array and vcalloc instead of array_size.
This also leaves a multiplication of a constant by a sizeof
as is.  Two patches are thus dropped from the series.

 drivers/gpu/drm/i915/gvt/gtt.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff -u -p a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -1969,14 +1969,16 @@ static struct intel_vgpu_mm *intel_vgpu_
 		return ERR_PTR(-ENOMEM);
 	}
 
-	mm->ggtt_mm.host_ggtt_aperture = vzalloc((vgpu_aperture_sz(vgpu) >> PAGE_SHIFT) * sizeof(u64));
+	mm->ggtt_mm.host_ggtt_aperture = vcalloc(vgpu_aperture_sz(vgpu) >> PAGE_SHIFT,
+						 sizeof(u64));
 	if (!mm->ggtt_mm.host_ggtt_aperture) {
 		vfree(mm->ggtt_mm.virtual_ggtt);
 		vgpu_free_mm(mm);
 		return ERR_PTR(-ENOMEM);
 	}
 
-	mm->ggtt_mm.host_ggtt_hidden = vzalloc((vgpu_hidden_sz(vgpu) >> PAGE_SHIFT) * sizeof(u64));
+	mm->ggtt_mm.host_ggtt_hidden = vcalloc(vgpu_hidden_sz(vgpu) >> PAGE_SHIFT,
+					       sizeof(u64));
 	if (!mm->ggtt_mm.host_ggtt_hidden) {
 		vfree(mm->ggtt_mm.host_ggtt_aperture);
 		vfree(mm->ggtt_mm.virtual_ggtt);