GPU-DRM-Savage: Less function calls in savage_bci_cmdbuf() after error detection

[SF Markus Elfring]

>> Date: Thu, 18 Aug 2016 21:28:58 +0200
>>
>> The kfree() function was called in a few cases by the
>> savage_bci_cmdbuf() function during error handling
>> even if a passed variable contained a null pointer.
>>
>> Adjust jump targets according to the Linux coding style convention.
>>
>> Signed-off-by: Markus Elfring 
> 
> Not sure this is worth it, I'll pass. Patch 1 merged.

Unfortunately, it seems that this selection of only one update step
from this small patch series has got unwanted consequences.

Will the update suggestion “[patch] drm/savage: dereferencing an error 
pointer”
by Dan Carpenter (from today) trigger further software development discussions?

https://patchwork.kernel.org/patch/9372127/
https://lkml.kernel.org/r/<20161012062227.GU12841 at mwanda>


Will an update step like “[PATCH 2/2] GPU-DRM-Savage: Less function calls in
savage_bci_cmdbuf() after error detection” (from 2016-08-18) become worth
for related consideratons once more?

https://patchwork.kernel.org/patch/9289183/
https://lkml.kernel.org/r/

Regards,
Markus

[PATCH 2/2] GPU-DRM-Savage: Less function calls in savage_bci_cmdbuf() after error detection

[Daniel Vetter]

On Thu, Aug 18, 2016 at 09:48:04PM +0200, SF Markus Elfring wrote:
> From: Markus Elfring 
> Date: Thu, 18 Aug 2016 21:28:58 +0200
> 
> The kfree() function was called in a few cases by the
> savage_bci_cmdbuf() function during error handling
> even if a passed variable contained a null pointer.
> 
> Adjust jump targets according to the Linux coding style convention.
> 
> Signed-off-by: Markus Elfring 

Not sure this is worth it, I'll pass. Patch 1 merged. Btw I consider
cocci patches a good way to get started somewhere, but then it's much more
useful to do a bit more involved things. We keep a list of small
janitor tasks:

https://www.x.org/wiki/DRMJanitors/

Cleaning up all the cocci errors in drm isn't good since then the next
person won't have something easy to get started, i.e. consider you're
budget used up ;-)
-Daniel

> ---
>  drivers/gpu/drm/savage/savage_state.c | 30 +++---
>  1 file changed, 15 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/savage/savage_state.c 
> b/drivers/gpu/drm/savage/savage_state.c
> index 3dc0d8f..5b484aa 100644
> --- a/drivers/gpu/drm/savage/savage_state.c
> +++ b/drivers/gpu/drm/savage/savage_state.c
> @@ -1004,7 +1004,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
> *data, struct drm_file *file_
>   kvb_addr = memdup_user(cmdbuf->vb_addr, cmdbuf->vb_size);
>   if (IS_ERR(kvb_addr)) {
>   ret = PTR_ERR(kvb_addr);
> - goto done;
> + goto free_cmd;
>   }
>   cmdbuf->vb_addr = kvb_addr;
>   }
> @@ -1013,13 +1013,13 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
> *data, struct drm_file *file_
> GFP_KERNEL);
>   if (kbox_addr == NULL) {
>   ret = -ENOMEM;
> - goto done;
> + goto free_vb;
>   }
>  
>   if (copy_from_user(kbox_addr, cmdbuf->box_addr,
>  cmdbuf->nbox * sizeof(struct 
> drm_clip_rect))) {
>   ret = -EFAULT;
> - goto done;
> + goto free_vb;
>   }
>   cmdbuf->box_addr = kbox_addr;
>   }
> @@ -1052,7 +1052,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
> *data, struct drm_file *file_
> "beyond end of command buffer\n");
>   DMA_FLUSH();
>   ret = -EINVAL;
> - goto done;
> + goto free_box;
>   }
>   /* fall through */
>   case SAVAGE_CMD_DMA_PRIM:
> @@ -1071,7 +1071,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
> *data, struct drm_file *file_
> cmdbuf->vb_stride,
> cmdbuf->nbox, cmdbuf->box_addr);
>   if (ret != 0)
> - goto done;
> + goto free_box;
>   first_draw_cmd = NULL;
>   }
>   }
> @@ -1086,7 +1086,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
> *data, struct drm_file *file_
> "beyond end of command buffer\n");
>   DMA_FLUSH();
>   ret = -EINVAL;
> - goto done;
> + goto free_box;
>   }
>   ret = savage_dispatch_state(dev_priv, _header,
>   (const uint32_t *)cmdbuf->cmd_addr);
> @@ -1099,7 +1099,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
> *data, struct drm_file *file_
> "beyond end of command buffer\n");
>   DMA_FLUSH();
>   ret = -EINVAL;
> - goto done;
> + goto free_box;
>   }
>   ret = savage_dispatch_clear(dev_priv, _header,
>   cmdbuf->cmd_addr,
> @@ -1117,12 +1117,12 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
> *data, struct drm_file *file_
> cmd_header.cmd.cmd);
>   DMA_FLUSH();
>   ret = -EINVAL;
> - goto done;
> + goto free_box;
>   }
>  
>   if (ret != 0) {
>   DMA_FLUSH();
> - goto done;
> + goto free_box;
>   }
>   }
>  
> @@ -1133,7 +1133,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
> *data, struct drm_file *file_
>   cmdbuf->nbox, cmdbuf->box_addr);
>   

[PATCH 2/2] GPU-DRM-Savage: Less function calls in savage_bci_cmdbuf() after error detection

[SF Markus Elfring]

From: Markus Elfring 
Date: Thu, 18 Aug 2016 21:28:58 +0200

The kfree() function was called in a few cases by the
savage_bci_cmdbuf() function during error handling
even if a passed variable contained a null pointer.

Adjust jump targets according to the Linux coding style convention.

Signed-off-by: Markus Elfring 
---
 drivers/gpu/drm/savage/savage_state.c | 30 +++---
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/savage/savage_state.c 
b/drivers/gpu/drm/savage/savage_state.c
index 3dc0d8f..5b484aa 100644
--- a/drivers/gpu/drm/savage/savage_state.c
+++ b/drivers/gpu/drm/savage/savage_state.c
@@ -1004,7 +1004,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void *data, 
struct drm_file *file_
kvb_addr = memdup_user(cmdbuf->vb_addr, cmdbuf->vb_size);
if (IS_ERR(kvb_addr)) {
ret = PTR_ERR(kvb_addr);
-   goto done;
+   goto free_cmd;
}
cmdbuf->vb_addr = kvb_addr;
}
@@ -1013,13 +1013,13 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
*data, struct drm_file *file_
  GFP_KERNEL);
if (kbox_addr == NULL) {
ret = -ENOMEM;
-   goto done;
+   goto free_vb;
}

if (copy_from_user(kbox_addr, cmdbuf->box_addr,
   cmdbuf->nbox * sizeof(struct 
drm_clip_rect))) {
ret = -EFAULT;
-   goto done;
+   goto free_vb;
}
cmdbuf->box_addr = kbox_addr;
}
@@ -1052,7 +1052,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void *data, 
struct drm_file *file_
  "beyond end of command buffer\n");
DMA_FLUSH();
ret = -EINVAL;
-   goto done;
+   goto free_box;
}
/* fall through */
case SAVAGE_CMD_DMA_PRIM:
@@ -1071,7 +1071,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void *data, 
struct drm_file *file_
  cmdbuf->vb_stride,
  cmdbuf->nbox, cmdbuf->box_addr);
if (ret != 0)
-   goto done;
+   goto free_box;
first_draw_cmd = NULL;
}
}
@@ -1086,7 +1086,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void *data, 
struct drm_file *file_
  "beyond end of command buffer\n");
DMA_FLUSH();
ret = -EINVAL;
-   goto done;
+   goto free_box;
}
ret = savage_dispatch_state(dev_priv, _header,
(const uint32_t *)cmdbuf->cmd_addr);
@@ -1099,7 +1099,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void *data, 
struct drm_file *file_
  "beyond end of command buffer\n");
DMA_FLUSH();
ret = -EINVAL;
-   goto done;
+   goto free_box;
}
ret = savage_dispatch_clear(dev_priv, _header,
cmdbuf->cmd_addr,
@@ -1117,12 +1117,12 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
*data, struct drm_file *file_
  cmd_header.cmd.cmd);
DMA_FLUSH();
ret = -EINVAL;
-   goto done;
+   goto free_box;
}

if (ret != 0) {
DMA_FLUSH();
-   goto done;
+   goto free_box;
}
}

@@ -1133,7 +1133,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void *data, 
struct drm_file *file_
cmdbuf->nbox, cmdbuf->box_addr);
if (ret != 0) {
DMA_FLUSH();
-   goto done;
+   goto free_box;
}
}

@@ -1147,11 +1147,11 @@ int savage_bci_cmdbuf(struct drm_device *dev, void 
*data, struct drm_file *file_
savage_freelist_put(dev, dmabuf);
}

-done:
-   /* If we didn't need to allocate them, these'll be NULL */
-   kfree(kcmd_addr);
-   kfree(kvb_addr);
+free_box:
kfree(kbox_addr);
-
+free_vb:
+   kfree(kvb_addr);
+free_cmd:
+