linux-kernel - [PATCH] virtio-gpu: Use memdup_user() rather than duplicating its implementation

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Date:   Thu, 18 Aug 2016 22:42:06 +0200
From:   SF Markus Elfring <elfring@...rs.sourceforge.net>
To:     dri-devel@...ts.freedesktop.org,
        virtualization@...ts.linux-foundation.org,
        David Airlie <airlied@...ux.ie>,
        Gerd Hoffmann <kraxel@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Julia Lawall <julia.lawall@...6.fr>
Subject: [PATCH] virtio-gpu: Use memdup_user() rather than duplicating its
 implementation

From: Markus Elfring <elfring@...rs.sourceforge.net>
Date: Thu, 18 Aug 2016 22:35:14 +0200

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index c046903..512e7cd 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -152,15 +152,10 @@ static int virtio_gpu_execbuffer(struct drm_device *dev,
 	if (ret)
 		goto out_free;
 
-	buf = kmalloc(exbuf->size, GFP_KERNEL);
-	if (!buf) {
-		ret = -ENOMEM;
-		goto out_unresv;
-	}
-	if (copy_from_user(buf, (void __user *)(uintptr_t)exbuf->command,
-			   exbuf->size)) {
-		kfree(buf);
-		ret = -EFAULT;
+	buf = memdup_user((void __user *)(uintptr_t)exbuf->command,
+			  exbuf->size);
+	if (IS_ERR(buf)) {
+		ret = PTR_ERR(buf);
 		goto out_unresv;
 	}
 	virtio_gpu_cmd_submit(vgdev, buf, exbuf->size,
-- 
2.9.3