Sorry, please ignore this V2, there is a typo in "goto out" at this patch.
I will send a "update V2" later.
Thanks,
Rui
On Wed, Sep 07, 2016 at 11:26:39AM +0800, Huang Rui wrote:
> In previous drm_global_item_ref, there are two times of writing
> ref->object if item->refcount is 0. So this patch does a minor update
> to put alloc and init ref firstly, and then to modify the item of glob
> array. Use "else" to avoid two times of writing ref->object. It can
> make the code logic more clearly.
>
> Signed-off-by: Huang Rui <ray.huang at amd.com>
> ---
>
> Changes from V1 -> V2:
> - Add kfree exceptional handle to avoid memory leak.
> - Improve code style.
>
> ---
> drivers/gpu/drm/drm_global.c | 25 +++++++++++++------------
> 1 file changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_global.c b/drivers/gpu/drm/drm_global.c
> index 3d2e91c..6a63808 100644
> --- a/drivers/gpu/drm/drm_global.c
> +++ b/drivers/gpu/drm/drm_global.c
> @@ -65,30 +65,31 @@ void drm_global_release(void)
>
> int drm_global_item_ref(struct drm_global_reference *ref)
> {
> - int ret;
> + int ret = -ENOMEM;
> struct drm_global_item *item = &glob[ref->global_type];
>
> mutex_lock(&item->mutex);
> if (item->refcount == 0) {
> - item->object = kzalloc(ref->size, GFP_KERNEL);
> - if (unlikely(item->object == NULL)) {
> - ret = -ENOMEM;
> + ref->object = kzalloc(ref->size, GFP_KERNEL);
> + if (unlikely(ref->object == NULL))
> goto out_err;
> - }
> -
> - ref->object = item->object;
> ret = ref->init(ref);
> if (unlikely(ret != 0))
> - goto out_err;
> + goto out;
>
> + item->object = ref->object;
> + } else {
> + ref->object = item->object;
> }
> +
> ++item->refcount;
> - ref->object = item->object;
> - mutex_unlock(&item->mutex);
> - return 0;
> + goto out;
> +
> out_err:
> + kfree(ref->object);
> + ref->object = NULL;
> +out:
> mutex_unlock(&item->mutex);
> - item->object = NULL;
> return ret;
> }
> EXPORT_SYMBOL(drm_global_item_ref);
> --
> 1.9.1
>
