linux-kernel - Re: [PATCH] io_uring: style: redundant NULL check.

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Message-ID: <bb01e932-9b93-c672-2e76-d8a2918d5bd6@infradead.org>
Date:   Tue, 29 Dec 2020 22:29:00 -0800
From:   Randy Dunlap <rdunlap@...radead.org>
To:     YANG LI <abaci-bugfix@...ux.alibaba.com>, axboe@...nel.dk
Cc:     viro@...iv.linux.org.uk, io-uring@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] io_uring: style: redundant NULL check.

On 12/29/20 10:22 PM, YANG LI wrote:
> If the pointer in kfree is empty, the function does nothing,
> so remove the redundant NULL check.
> 
> Signed-off-by: YANG LI <abaci-bugfix@...ux.alibaba.com>
> Reported-by: Abaci <abaci@...ux.alibaba.com>
> ---

Looks like you should do something with these 2 comments:

 	/* it's reportedly faster than delegating the null check to kfree() */

>  fs/io_uring.c | 13 +++++--------
>  1 file changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 7e35283..105e188 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -1934,8 +1934,8 @@ static void io_dismantle_req(struct io_kiocb *req)
>  {
>  	io_clean_op(req);
>  
> -	if (req->async_data)
> -		kfree(req->async_data);
> +	kfree(req->async_data);
> +
>  	if (req->file)
>  		io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
>  	if (req->fixed_file_refs)
> @@ -3537,8 +3537,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
>  	ret = 0;
>  out_free:
>  	/* it's reportedly faster than delegating the null check to kfree() */
> -	if (iovec)
> -		kfree(iovec);
> +	kfree(iovec);
>  	return ret;
>  }
>  
> @@ -3644,8 +3643,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
>  	}
>  out_free:
>  	/* it's reportedly faster than delegating the null check to kfree() */
> -	if (iovec)
> -		kfree(iovec);
> +	kfree(iovec);
>  	return ret;
>  }
>  
> @@ -6133,8 +6131,7 @@ static void __io_clean_op(struct io_kiocb *req)
>  		case IORING_OP_WRITE_FIXED:
>  		case IORING_OP_WRITE: {
>  			struct io_async_rw *io = req->async_data;
> -			if (io->free_iovec)
> -				kfree(io->free_iovec);
> +			kfree(io->free_iovec);
>  			break;
>  			}
>  		case IORING_OP_RECVMSG:
> 


-- 
~Randy