[PATCH] drm/amdgpu: Modify error handling in amdgpu_ttm

[Amitoj Kaur Chawla]

To indicate an error, debugfs_create_file can return an ERR_PTR for
!CONFIG_DEBUG_FS and NULL otherwise, so in case the result is
dereferenced there should be a previous IS_ERR and a NULL check.

The Coccinelle semantic patch used to find the issue is as follows:
@@
expression e;
identifier f;
@@

*  e = debugfs_create_file(...);
... when != e == NULL
e->f

Signed-off-by: Amitoj Kaur Chawla <amitoj1...@gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 8a1752f..9ff70a7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1198,6 +1198,8 @@ static int amdgpu_ttm_debugfs_init(struct amdgpu_device 
*adev)
                                  adev, &amdgpu_ttm_vram_fops);
        if (IS_ERR(ent))
                return PTR_ERR(ent);
+       if (!ent)
+               return -ENOMEM;
        i_size_write(ent->d_inode, adev->mc.mc_vram_size);
        adev->mman.vram = ent;
 
@@ -1205,6 +1207,8 @@ static int amdgpu_ttm_debugfs_init(struct amdgpu_device 
*adev)
                                  adev, &amdgpu_ttm_gtt_fops);
        if (IS_ERR(ent))
                return PTR_ERR(ent);
+       if (!ent)
+               return -ENOMEM;
        i_size_write(ent->d_inode, adev->mc.gtt_size);
        adev->mman.gtt = ent;
 
-- 
1.9.1