netdev - Re: [PATCH mlx5-next v1 05/15] net/mlx5: Break encap/decap into two separated flow table creation flags

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Message-ID: <20180905163800.GA21028@ziepe.ca>
Date:   Wed, 5 Sep 2018 10:38:00 -0600
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     Leon Romanovsky <leon@...nel.org>
Cc:     Doug Ledford <dledford@...hat.com>,
        RDMA mailing list <linux-rdma@...r.kernel.org>,
        Ariel Levkovich <lariel@...lanox.com>,
        Mark Bloch <markb@...lanox.com>,
        Or Gerlitz <ogerlitz@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>,
        linux-netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH mlx5-next v1 05/15] net/mlx5: Break encap/decap into two
 separated flow table creation flags

On Wed, Sep 05, 2018 at 08:10:25AM +0300, Leon Romanovsky wrote:
> > > -	int en_encap_decap = !!(flags & MLX5_FLOW_TABLE_TUNNEL_EN);
> > > +	int en_encap = !!(flags & MLX5_FLOW_TABLE_TUNNEL_EN_ENCAP);
> > > +	int en_decap = !!(flags & MLX5_FLOW_TABLE_TUNNEL_EN_DECAP);
> >
> > Yuk, please don't use !!.
> >
> > 	bool en_decap = flags & MLX5_FLOW_TABLE_TUNNEL_EN_DECAP;
> 
> We need to provide en_encap and en_decap as an input to MLX5_SET(...)
> which is passed to FW as 0 or 1. 
>
> Boolean type is declared in C as int and treated as zero for false
> and any other value for true,

No, that isn't right, the kernel uses C99's _Bool intrinsic type, which
is guaranteed to only hold 0 or 1 by the compiler.

See types.h:

typedef _Bool                   bool;

Jason