2013-03-11 19:31:23

by Alexandru Gheorghiu

Subject: [PATCH] drivers: gpu: drm: i915: Replaced calls to kmalloc & memcpy with kmemdup

Replaced calls to kmalloc followed by memcpy with a single call to kmemdup.
This patch was found using coccinelle.

Signed-off-by: Alexandru Gheorghiu <[email protected]>
---
drivers/gpu/drm/i915/intel_dp.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index f61cb79..a3fdd65 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2335,11 +2335,10 @@ intel_dp_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
return NULL;

size = (intel_connector->edid->extensions + 1) * EDID_LENGTH;
- edid = kmalloc(size, GFP_KERNEL);
+ edid = kmemdup(intel_connector->edid, size, GFP_KERNEL);
if (!edid)
return NULL;

- memcpy(edid, intel_connector->edid, size);
return edid;
}

--
1.7.9.5

2013-03-11 21:09:48

by Josh Triplett

Subject: Re: [PATCH] drivers: gpu: drm: i915: Replaced calls to kmalloc & memcpy with kmemdup

On Mon, Mar 11, 2013 at 09:30:40PM +0200, Alexandru Gheorghiu wrote:
> Replaced calls to kmalloc followed by memcpy with a single call to kmemdup.
> This patch was found using coccinelle.
>
> Signed-off-by: Alexandru Gheorghiu <[email protected]>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index f61cb79..a3fdd65 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -2335,11 +2335,10 @@ intel_dp_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
> return NULL;
>
> size = (intel_connector->edid->extensions + 1) * EDID_LENGTH;
> - edid = kmalloc(size, GFP_KERNEL);
> + edid = kmemdup(intel_connector->edid, size, GFP_KERNEL);
> if (!edid)
> return NULL;
>
> - memcpy(edid, intel_connector->edid, size);
> return edid;
> }

With this change, the conditional no longer makes sense; this should
just "return kmemdup(...);".

That suggests an obvious further cleanup that coccinelle could easily
handle:

if (!foo)
return NULL;
return foo;

should become just "return foo;". And you might then want to check for
variables used *only* to capture a return value and immediately
returned, and eliminate them.

- Josh Triplett