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Message-ID: <6064a6d7-8790-cf15-2d2e-eddb04e4e668@linux.alibaba.com>
Date:   Tue, 12 Dec 2023 21:26:53 +0800
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Subject: Re: [PATCH v3 31/35] net: smc: optimize
 smc_wr_tx_get_free_slot_index()
To:     Yury Norov <yury.norov@gmail.com>, linux-kernel@vger.kernel.org,
        Karsten Graul <kgraul@linux.ibm.com>,
        Wenjia Zhang <wenjia@linux.ibm.com>,
        Jan Karcher <jaka@linux.ibm.com>,
        "D. Wythe" <alibuda@linux.alibaba.com>,
        Tony Lu <tonylu@linux.alibaba.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, linux-s390@vger.kernel.org,
        netdev@vger.kernel.org
Cc:     Jan Kara <jack@suse.cz>,
        Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>,
        Matthew Wilcox <willy@infradead.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org>,
        Alexey Klimov <klimov.linux@gmail.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Sergey Shtylyov <s.shtylyov@omp.ru>,
        Alexandra Winter <wintera@linux.ibm.com>
References: <20231212022749.625238-1-yury.norov@gmail.com>
 <20231212022749.625238-32-yury.norov@gmail.com>
From:   Wen Gu <guwen@linux.alibaba.com>
In-Reply-To: <20231212022749.625238-32-yury.norov@gmail.com>
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On 2023/12/12 10:27, Yury Norov wrote:

> Simplify the function by using find_and_set_bit() and make it a simple
> almost one-liner.
> 
> While here, drop explicit initialization of *idx, because it's already
> initialized by the caller in case of ENOLINK, or set properly with
> ->wr_tx_mask, if nothing is found, in case of EBUSY.
> 
> CC: Tony Lu <tonylu@linux.alibaba.com>
> Signed-off-by: Yury Norov <yury.norov@gmail.com>
> Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
> ---
>   net/smc/smc_wr.c | 10 +++-------
>   1 file changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
> index 0021065a600a..b6f0cfc52788 100644
> --- a/net/smc/smc_wr.c
> +++ b/net/smc/smc_wr.c
> @@ -170,15 +170,11 @@ void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
>   
>   static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
>   {
> -	*idx = link->wr_tx_cnt;
>   	if (!smc_link_sendable(link))
>   		return -ENOLINK;
> -	for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
> -		if (!test_and_set_bit(*idx, link->wr_tx_mask))
> -			return 0;
> -	}
> -	*idx = link->wr_tx_cnt;
> -	return -EBUSY;
> +
> +	*idx = find_and_set_bit(link->wr_tx_mask, link->wr_tx_cnt);
> +	return *idx < link->wr_tx_cnt ? 0 : -EBUSY;
>   }
>   
>   /**

Thank you! Yury.

Reviewed-by: Wen Gu <guwen@linux.alibaba.com>