Am 30.04.20 um 13:00 schrieb Bernard:
发件人：Joe Perches joe@perches.com 发送日期：2020-04-27 01:53:06 收件人："Christian König" christian.koenig@amd.com,Bernard Zhao bernard@vivo.com,Alex Deucher alexander.deucher@amd.com,"David (ChunMing) Zhou" David1.Zhou@amd.com,David Airlie airlied@linux.ie,Daniel Vetter daniel@ffwll.ch,amd-gfx@lists.freedesktop.org,dri-devel@lists.freedesktop.org,linux-kernel@vger.kernel.org 抄送人：opensource.kernel@vivo.com 主题：Re: [PATCH] drm/radeon: cleanup coding style a bit>On Sun, 2020-04-26 at 15:18 +0200, Christian König wrote:
Am 26.04.20 um 15:12 schrieb Bernard Zhao:
Maybe no need to check ws before kmalloc, kmalloc will check itself, kmalloc`s logic is if ptr is NULL, kmalloc will just return
Signed-off-by: Bernard Zhao bernard@vivo.com
Reviewed-by: Christian König christian.koenig@amd.com
I'm wondering why the automated scripts haven't found that one before.
because this pattern is
if (foo) kfree(bar);
and the pattern looked for is:
if (foo) kfree(foo);
diff --git a/drivers/gpu/drm/radeon/atom.c b/drivers/gpu/drm/radeon/atom.c
[]
@@ -1211,8 +1211,7 @@ static int atom_execute_table_locked(struct atom_context *ctx, int index, uint32 SDEBUG("<<\n");
free:
- if (ws)
kfree(ectx.ws);
- kfree(ectx.ws); return ret; }
I'm wondering if this removal is correct as the function is named _locked and it may be recursive or called under some external lock.
Hi I am a little confused about this. I understand that the caller guarantees the lock protection that we will not release the wrong pointer. And the NULL check is the same with the first check in kfree? Maybe we do not need check twich.
I don't understand the comment either. When you look at the function you see that code is freeing up the temporary allocated buffer which is to large for the stack.
In other words we kcalloc() this buffer a few lines above and free it here again. So I think the patch is perfectly valid.
What we could do is to update the coci pattern to catch this as well, but this case is so rare that it is probably not worth it.
Regards, Christian.
Regards, Bernard
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