Re:Re: [PATCH V3] amdgpu: remove unnecessary condition check

[赵军奎]

From: "Christian König" <christian.koenig at amd.com>
Date: 2020-04-21 16:06:03
To:  1587180037-113840-1-git-send-email-bernard at vivo.com,Felix Kuehling <Felix.Kuehling at amd.com>,Alex Deucher <alexander.deucher at amd.com>,"David (ChunMing) Zhou" <David1.Zhou at amd.com>,David Airlie <airlied at linux.ie>,Daniel Vetter <daniel at ffwll.ch>,amd-gfx at lists.freedesktop.org,dri-devel at lists.freedesktop.org,linux-kernel at vger.kernel.org
Cc:  opensource.kernel at vivo.com,Bernard Zhao <bernard at vivo.com>
Subject: Re: [PATCH V3] amdgpu: remove unnecessary condition check>Am 21.04.20 um 10:03 schrieb Bernard Zhao:
>> There is no need to if check again, maybe we could merge
>> into the above else branch.
>>
>> Signed-off-by: Bernard Zhao <bernard at vivo.com>
>>
>> Changes since V1:
>> *commit message improve
>> *code style refactoring
>>
>> Changes since V2:
>> *code style adjust
>>
>> Link for V1:
>> *https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fpatchwork%2Fpatch%2F1226587%2F&data=02%7C01%7Cchristian.koenig%40amd.com%7C0b8fffafb715474289b208d7e5ca7f6c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637230530201280350&sdata=Sewv5ESX%2B0B4DbFbE03uM5sifrEcmJllC8pt7J42I7M%3D&reserved=0
>> ---
>>   .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c   | 18 +++++++-----------
>>   1 file changed, 7 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> index 9dff792c9290..5424bd921a7b 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> @@ -660,13 +660,12 @@ static int reserve_bo_and_vm(struct kgd_mem *mem,
>>   
>>   	ret = ttm_eu_reserve_buffers(&ctx->ticket, &ctx->list,
>>   				     false, &ctx->duplicates);
>> -	if (!ret)
>> -		ctx->reserved = true;
>> -	else {
>> -		pr_err("Failed to reserve buffers in ttm\n");
>> +	if (ret) {
>> +		pr_err("Failed to reserve buffers in ttm.\n");
>>   		kfree(ctx->vm_pd);
>>   		ctx->vm_pd = NULL;
>> -	}
>> +	} else
>> +		ctx->reserved = true;
>
>That is still not correct coding style. In general when one branch of an 
>if/else uses {} the other one should use it as well.
>
>But I agree with Felix that this change looks rather superfluous to me 
>as well.
>
>Regards,
>Christian.

About the code style, you are right, I checked the refers:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?id=90280eaa88ac1a9140dc759941123530d5545bb6#n191
The if and else should use the same style.
But i have to say there are so many code not follow the kernel code-style in amdgpu module.
And also the ./scripts/checkpatch.pl did not throw any warning or error.

If this change looks rather superfluous to all of you, should i change to the V1 change?
After all i don`t think there is any necessary to check "ret" again, merge the <else and if (ret)>
maybe better.
Original code:
static int reserve_bo_and_cond_vms(struct kgd_mem *mem,.....
	if (!ret)
		ctx->reserved = true;
	else
		pr_err("Failed to reserve buffers in ttm.\n");

	if (ret) {
		kfree(ctx->vm_pd);
		ctx->vm_pd = NULL;
	}

BR//bernard

>>   
>>   	return ret;
>>   }
>> @@ -733,15 +732,12 @@ static int reserve_bo_and_cond_vms(struct kgd_mem *mem,
>>   
>>   	ret = ttm_eu_reserve_buffers(&ctx->ticket, &ctx->list,
>>   				     false, &ctx->duplicates);
>> -	if (!ret)
>> -		ctx->reserved = true;
>> -	else
>> -		pr_err("Failed to reserve buffers in ttm.\n");
>> -
>>   	if (ret) {
>> +		pr_err("Failed to reserve buffers in ttm.\n");
>>   		kfree(ctx->vm_pd);
>>   		ctx->vm_pd = NULL;
>> -	}
>> +	} else
>> +		ctx->reserved = true;
>>   
>>   	return ret;
>>   }
>