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From:   David Laight <David.Laight@ACULAB.COM>
To:     'zhouchuangao' <zhouchuangao@vivo.com>,
        David Howells <dhowells@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        "Jakub Kicinski" <kuba@kernel.org>,
        "linux-afs@lists.infradead.org" <linux-afs@lists.infradead.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] net/rxrpc: Use BUG_ON instead of if condition followed by
 BUG.
Thread-Topic: [PATCH] net/rxrpc: Use BUG_ON instead of if condition followed
 by BUG.
Thread-Index: AQHXPM/tVVdxd6dES0eMiUm+pJEO+6rLLuow
Date:   Thu, 29 Apr 2021 08:48:18 +0000
Message-ID: <e7c1b060f1594d21bab96e68c4b53bb3@AcuMS.aculab.com>
References: <1619683852-2247-1-git-send-email-zhouchuangao@vivo.com>
In-Reply-To: <1619683852-2247-1-git-send-email-zhouchuangao@vivo.com>
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From: zhouchuangao
> Sent: 29 April 2021 09:11
> 
> BUG_ON() uses unlikely in if(), which can be optimized at compile time.
> 
>               do { if (unlikely(condition)) BUG(); } while (0)
...
> diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
> index 4eb91d95..e5deb6f 100644
> --- a/net/rxrpc/call_object.c
> +++ b/net/rxrpc/call_object.c
> @@ -505,8 +505,7 @@ void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
>  	ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
> 
>  	spin_lock_bh(&call->lock);
> -	if (test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags))
> -		BUG();
> +	BUG_ON(test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags));

Hiding as assignment inside BUG_ON() isn't nice.

	David

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