netdev - Re: [PATCH net-next] net/smc: cast sizeof to int for comparison

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Message-ID: <87zhwj6liz.fsf@igel.home>
Date:   Sat, 15 Sep 2018 13:35:32 +0200
From:   Andreas Schwab <schwab@...ux-m68k.org>
To:     YueHaibing <yuehaibing@...wei.com>
Cc:     <davem@...emloft.net>, <ubraun@...ux.ibm.com>,
        <linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>,
        <linux-s390@...r.kernel.org>
Subject: Re: [PATCH net-next] net/smc: cast sizeof to int for comparison

On Sep 15 2018, YueHaibing <yuehaibing@...wei.com> wrote:

> Comparing an int to a size, which is unsigned, causes the int to become
> unsigned, giving the wrong result. kernel_sendmsg can return a negative
> error code.
>
> Signed-off-by: YueHaibing <yuehaibing@...wei.com>
> ---
>  net/smc/smc_clc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
> index 83aba9a..fd0f5ce 100644
> --- a/net/smc/smc_clc.c
> +++ b/net/smc/smc_clc.c
> @@ -446,7 +446,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
>  	vec[i++].iov_len = sizeof(trl);
>  	/* due to the few bytes needed for clc-handshake this cannot block */
>  	len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
> -	if (len < sizeof(pclc)) {
> +	if (len < (int)sizeof(pclc)) {
>  		if (len >= 0) {
>  			reason_code = -ENETUNREACH;
>  			smc->sk.sk_err = -reason_code;

It would perhaps be better to handle len < 0 first.

Andreas.

-- 
Andreas Schwab, schwab@...ux-m68k.org
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