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From: Jens Axboe <[email protected]>
To: Stefano Garzarella <[email protected]>,
	Zhang chunchao <[email protected]>
Cc: [email protected], [email protected],
	[email protected], [email protected]
Subject: Re: [PATCH] Modify the return value ret to EOPNOTSUPP when initialized to reduce repeated assignment of errno
Date: Thu, 11 Aug 2022 09:41:38 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <20220811150242.giygjmy4vimxtrzg@sgarzare-redhat>

On 8/11/22 9:02 AM, Stefano Garzarella wrote:
> On Thu, Aug 11, 2022 at 03:56:38PM +0800, Zhang chunchao wrote:
>> Remove unnecessary initialization assignments.
>>
>> Signed-off-by: Zhang chunchao <[email protected]>
>> ---
>> io_uring/io_uring.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
>> index b54218da075c..8c267af06401 100644
>> --- a/io_uring/io_uring.c
>> +++ b/io_uring/io_uring.c
>> @@ -3859,14 +3859,13 @@ SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
>>         void __user *, arg, unsigned int, nr_args)
>> {
>>     struct io_ring_ctx *ctx;
>> -    long ret = -EBADF;
>> +    long ret = -EOPNOTSUPP;
>>     struct fd f;
>>
>>     f = fdget(fd);
>>     if (!f.file)
>>         return -EBADF;
>>
>> -    ret = -EOPNOTSUPP;
>>     if (!io_is_uring_fops(f.file))
>>         goto out_fput;
>>
> 
> What about remove the initialization and assign it in the if branch?
> I find it a bit easier to read.
> 
> I mean something like this:
> 
> --- a/io_uring/io_uring.c
> +++ b/io_uring/io_uring.c
> @@ -3859,16 +3859,17 @@ SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
>                 void __user *, arg, unsigned int, nr_args)
>  {
>         struct io_ring_ctx *ctx;
> -       long ret = -EBADF;
> +       long ret;
>         struct fd f;
> 
>         f = fdget(fd);
>         if (!f.file)
>                 return -EBADF;
> 
> -       ret = -EOPNOTSUPP;
> -       if (!io_is_uring_fops(f.file))
> +       if (!io_is_uring_fops(f.file)) {
> +               ret = -EOPNOTSUPP;
>                 goto out_fput;
> +       }
> 
>         ctx = f.file->private_data;
> 
> 
> Otherwise remove the initialization, but leave the assignment as it is now.

Generally the kernel likes to do:

err = -EFOO;
if (something)
	goto err_out;

rather than put it inside the if clause. I guess the rationale is it
makes it harder to forget to init the error value. I don't feel too
strongly, I'm fine with your patch too. Can you send it as a real patch?

-- 
Jens Axboe


  reply	other threads:[~2022-08-11 15:49 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-11  7:56 [PATCH] Modify the return value ret to EOPNOTSUPP when initialized to reduce repeated assignment of errno Zhang chunchao
2022-08-11 15:02 ` Stefano Garzarella
2022-08-11 15:41   ` Jens Axboe [this message]
2022-08-11 18:42     ` Stefano Garzarella

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