linux-kernel - Re: [PATCH 3/4] cpumask: add cpumask_{first,next}

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aAmo83SnYBGv7zRu@yury>
Date: Wed, 23 Apr 2025 22:58:59 -0400
From: Yury Norov <yury.norov@...il.com>
To: Reinette Chatre <reinette.chatre@...el.com>
Cc: Tony Luck <tony.luck@...el.com>, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] cpumask: add cpumask_{first,next}_andnot() API

On Wed, Apr 23, 2025 at 02:28:38PM -0700, Reinette Chatre wrote:
> Hi Yury,
> 
> On 4/7/25 8:38 AM, Yury Norov wrote:
> 
> ...
> 
> > @@ -284,6 +297,25 @@ unsigned int cpumask_next_and(int n, const struct cpumask *src1p,
> >  		small_cpumask_bits, n + 1);
> >  }
> >  
> > +/**
> > + * cpumask_next_andnot - get the next cpu in *src1p & ~*src2p
> > + * @n: the cpu prior to the place to search (i.e. return will be > @n)
> > + * @src1p: the first cpumask pointer
> > + * @src2p: the second cpumask pointer
> > + *
> > + * Return: >= nr_cpu_ids if no further cpus set in both.
> > + */
> > +static __always_inline
> > +unsigned int cpumask_next_andnot(int n, const struct cpumask *src1p,
> > +				 const struct cpumask *src2p)
> 
> Looks like the custom followed here is to name parameter that can have
> -1 as value "n" and let it have type "int". Should this also apply to
> cpumask_andnot_any_but(), cpumask_any_but(), and cpumask_any_and_but()
> modified/introduced in this series?
> 
> > +{
> > +	/* -1 is a legal arg here. */
> > +	if (n != -1)
> > +		cpumask_check(n);
> > +	return find_next_andnot_bit(cpumask_bits(src1p), cpumask_bits(src2p),
> > +		small_cpumask_bits, n + 1);
> > +}
> > +
> >  /**
> >   * cpumask_next_and_wrap - get the next cpu in *src1p & *src2p, starting from
> >   *			   @n+1. If nothing found, wrap around and start from
> > @@ -458,6 +490,33 @@ unsigned int cpumask_any_and_but(const struct cpumask *mask1,
> >  	return cpumask_next_and(cpu, mask1, mask2);
> >  }
> >  
> > +/**
> > + * cpumask_andnot_any_but - pick an arbitrary cpu from *mask1 & ~*mask2, but not this one.
> > + * @mask1: the first input cpumask
> > + * @mask2: the second input cpumask
> > + * @cpu: the cpu to ignore
> > + *
> > + * If @cpu == -1, the function returns the first matching cpu.
> > + * Returns >= nr_cpu_ids if no cpus set.
> > + */
> > +static __always_inline
> > +unsigned int cpumask_andnot_any_but(const struct cpumask *mask1,
> > +				    const struct cpumask *mask2,
> > +				    unsigned int cpu)
> 
> Since -1 is legal argument I expect "cpu" to be int.

Yes, you're right. I overlooked this. Will fix in v2