linux-kernel - RE: [PATCH 03/49] net: mellanox: fix open-coded for_each_set

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Date:   Fri, 11 Feb 2022 09:01:18 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Yury Norov' <yury.norov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Joe Perches <joe@...ches.com>, Dennis Zhou <dennis@...nel.org>,
        Emil Renner Berthing <kernel@...il.dk>,
        Nicholas Piggin <npiggin@...il.com>,
        Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
        Alexey Klimov <aklimov@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Rikard Falkeborn <rikard.falkeborn@...il.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>
CC:     Tariq Toukan <tariqt@...dia.com>
Subject: RE: [PATCH 03/49] net: mellanox: fix open-coded for_each_set_bit()

From: Yury Norov
> Sent: 10 February 2022 22:49
> 
> Mellanox driver has an open-coded for_each_set_bit(). Fix it.
> 
> Signed-off-by: Yury Norov <yury.norov@...il.com>
> Reviewed-by: Tariq Toukan <tariqt@...dia.com>
> ---
>  drivers/net/ethernet/mellanox/mlx4/cmd.c | 23 ++++++-----------------
>  1 file changed, 6 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c
> index e10b7b04b894..c56d2194cbfc 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c
> @@ -1994,21 +1994,16 @@ static void mlx4_allocate_port_vpps(struct mlx4_dev *dev, int port)
> 
>  static int mlx4_master_activate_admin_state(struct mlx4_priv *priv, int slave)
>  {
> -	int port, err;
> +	int p, port, err;
>  	struct mlx4_vport_state *vp_admin;
>  	struct mlx4_vport_oper_state *vp_oper;
>  	struct mlx4_slave_state *slave_state =
>  		&priv->mfunc.master.slave_state[slave];
>  	struct mlx4_active_ports actv_ports = mlx4_get_active_ports(
>  			&priv->dev, slave);
> -	int min_port = find_first_bit(actv_ports.ports,
> -				      priv->dev.caps.num_ports) + 1;
> -	int max_port = min_port - 1 +
> -		bitmap_weight(actv_ports.ports, priv->dev.caps.num_ports);
> 
> -	for (port = min_port; port <= max_port; port++) {
> -		if (!test_bit(port - 1, actv_ports.ports))
> -			continue;
> +	for_each_set_bit(p, actv_ports.ports, priv->dev.caps.num_ports) {
> +		port = p + 1;

This is an 'interesting' change in behaviour, and looks like a bug fix.
Did anyone actually test the old code?

	David

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