linux-kernel - Re: [PATCH] io_uring: fix ifnullfree.cocci warnings

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Date:   Wed, 10 Apr 2019 14:25:47 +0800
From:   "jianchao.wang" <jianchao.w.wang@...cle.com>
To:     Julia Lawall <julia.lawall@...6.fr>
Cc:     axboe@...nel.dk, viro@...iv.linux.org.uk,
        linux-block@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, kbuild-all@...org
Subject: Re: [PATCH] io_uring: fix ifnullfree.cocci warnings



On 4/10/19 2:16 PM, Julia Lawall wrote:
> From: kbuild test robot <lkp@...el.com>
> 
> NULL check before kfree is not needed.
> 
> Generated by: scripts/coccinelle/free/ifnullfree.cocci
> 
> Fixes: b905f31ee046 ("io_uring: introduce inline reqs for IORING_SETUP_IOPOLL")
> CC: Jianchao Wang <jianchao.w.wang@...cle.com>
> Signed-off-by: kbuild test robot <lkp@...el.com>
> Signed-off-by: Julia Lawall <julia.lawall@...6.fr>
> 
> ---
> 
> url:    https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_0day-2Dci_linux_commits_Jianchao-2DWang_io-5Furing-2Dintroduce-2Dinline-2Dreqs-2Dfor-2DIORING-5FSETUP-5FIOPOLL_20190409-2D194746&d=DwIBAg&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=7WdAxUBeiTUTCy8v-7zXyr4qk7sx26ATvfo6QSTvZyQ&m=JhagBidUFU8krcGWek4GwnU4uoqS09eboyA8kslpNts&s=fcK4IjSBbR0XznBh7lL6V47NyfxmdixfO3QXiWWVuX0&e=
> :::::: branch date: 17 hours ago
> :::::: commit date: 17 hours ago
> 
>  io_uring.c |    3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -2597,8 +2597,7 @@ static void io_ring_ctx_free(struct io_r
>  		sock_release(ctx->ring_sock);
>  #endif
> 
> -	if (ctx->inline_req_array)
> -		kfree(ctx->inline_req_array);
> +	kfree(ctx->inline_req_array);

Yes, indeed. kfree can tolerate NULL pointer.
Will change it in latter version.

Thanks
Jianchao

> 
>  	io_mem_free(ctx->sq_ring);
>  	io_mem_free(ctx->sq_sqes);
>