[PATCH 5.10.y] drm/virtio: Fix error code in virtio_gpu_object_shmem_init()

From: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
To: dmitry.osipenko@collabora.com, stable@vger.kernel.org
Cc: kraxel@redhat.com, linux-kernel@vger.kernel.org,
	emil.l.velikov@gmail.com, airlied@linux.ie, error27@gmail.com,
	gregkh@linuxfoundation.org, darren.kenny@oracle.com,
	vegard.nossum@oracle.com,
	Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Subject: [PATCH 5.10.y] drm/virtio: Fix error code in virtio_gpu_object_shmem_init()
Date: Thu,  2 Mar 2023 09:28:16 -0800	[thread overview]
Message-ID: <20230302172816.3508816-1-harshit.m.mogalapalli@oracle.com> (raw)

In virtio_gpu_object_shmem_init() we are passing NULL to PTR_ERR, which
is returning 0/success.

Fix this by storing error value in 'ret' variable before assigning
shmem->pages to NULL.

Found using static analysis with Smatch.

Fixes: 64b88afbd92f ("drm/virtio: Correct drm_gem_shmem_get_sg_table() error handling")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
---
Only compile tested.

Upstream commit b5c9ed70d1a9 ("drm/virtio: Improve DMA API usage for shmem BOs")
deleted this code, so this patch is not necessary in linux-6.1.y and
linux-6.2.y.
---
 drivers/gpu/drm/virtio/virtgpu_object.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index 168148686001..49fa59e09187 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -159,8 +159,9 @@ static int virtio_gpu_object_shmem_init(struct virtio_gpu_device *vgdev,
 	shmem->pages = drm_gem_shmem_get_sg_table(&bo->base.base);
 	if (IS_ERR(shmem->pages)) {
 		drm_gem_shmem_unpin(&bo->base.base);
+		ret = PTR_ERR(shmem->pages);
 		shmem->pages = NULL;
-		return PTR_ERR(shmem->pages);
+		return ret;
 	}
 
 	if (use_dma_api) {
-- 
2.31.1

