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Subject: Re: [PATCH net-next v5 08/18] net: sparx5: Replace usage of found
 with dedicated list iterator variable
From:   Paolo Abeni <pabeni@redhat.com>
To:     Jakob Koschel <jakobkoschel@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Cc:     Jakub Kicinski <kuba@kernel.org>, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        Lars Povlsen <lars.povlsen@microchip.com>,
        Steen Hegelund <Steen.Hegelund@microchip.com>,
        UNGLinuxDriver@microchip.com, Ariel Elior <aelior@marvell.com>,
        Manish Chopra <manishc@marvell.com>,
        Edward Cree <ecree.xilinx@gmail.com>,
        Martin Habets <habetsm.xilinx@gmail.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Jiri Pirko <jiri@resnulli.us>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Casper Andersson <casper.casan@gmail.com>,
        Arnd Bergmann <arnd@arndb.de>, Jason Gunthorpe <jgg@ziepe.ca>,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Colin Ian King <colin.king@intel.com>,
        Eric Dumazet <edumazet@google.com>,
        Xu Wang <vulab@iscas.ac.cn>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linuxppc-dev@lists.ozlabs.org, bpf@vger.kernel.org,
        Mike Rapoport <rppt@kernel.org>,
        Brian Johannesmeyer <bjohannesmeyer@gmail.com>,
        Cristiano Giuffrida <c.giuffrida@vu.nl>,
        "Bos, H.J." <h.j.bos@vu.nl>
Date:   Thu, 28 Apr 2022 11:32:28 +0200
In-Reply-To: <20220427160635.420492-9-jakobkoschel@gmail.com>
References: <20220427160635.420492-1-jakobkoschel@gmail.com>
         <20220427160635.420492-9-jakobkoschel@gmail.com>
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Hello,

On Wed, 2022-04-27 at 18:06 +0200, Jakob Koschel wrote:
> To move the list iterator variable into the list_for_each_entry_*()
> macro in the future it should be avoided to use the list iterator
> variable after the loop body.
> 
> To *never* use the list iterator variable after the loop it was
> concluded to use a separate iterator variable instead of a
> found boolean [1].
> 
> This removes the need to use a found variable and simply checking if
> the variable was set, can determine if the break/goto was hit.
> 
> Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
> Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
> ---
>  .../microchip/sparx5/sparx5_mactable.c        | 25 +++++++++----------
>  1 file changed, 12 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c b/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c
> index a5837dbe0c7e..bb8d9ce79ac2 100644
> --- a/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c
> +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c
> @@ -362,8 +362,7 @@ static void sparx5_mact_handle_entry(struct sparx5 *sparx5,
>  				     unsigned char mac[ETH_ALEN],
>  				     u16 vid, u32 cfg2)
>  {
> -	struct sparx5_mact_entry *mact_entry;
> -	bool found = false;
> +	struct sparx5_mact_entry *mact_entry = NULL, *iter;
>  	u16 port;
>  
>  	if (LRN_MAC_ACCESS_CFG_2_MAC_ENTRY_ADDR_TYPE_GET(cfg2) !=
> @@ -378,28 +377,28 @@ static void sparx5_mact_handle_entry(struct sparx5 *sparx5,
>  		return;
>  
>  	mutex_lock(&sparx5->mact_lock);
> -	list_for_each_entry(mact_entry, &sparx5->mact_entries, list) {
> -		if (mact_entry->vid == vid &&
> -		    ether_addr_equal(mac, mact_entry->mac)) {
> -			found = true;
> -			mact_entry->flags |= MAC_ENT_ALIVE;
> -			if (mact_entry->port != port) {
> +	list_for_each_entry(iter, &sparx5->mact_entries, list) {
> +		if (iter->vid == vid &&
> +		    ether_addr_equal(mac, iter->mac)) {

I'm sorry for the late feedback.

If you move the 'mact_entry = iter;' statement here, the diffstat will
be slightly smaller and the patch more readable, IMHO.

There is similar situation in the next patch.

Cheers,

Paolo