Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | Re: [PATCH] cpumask: introduce new API, without changing anything | Date | Fri, 7 Nov 2008 22:32:02 +1100 |
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On Friday 07 November 2008 19:52:29 Andrew Morton wrote: > So I can happily compile and run > > cpumask_first("hello, world"); > > with CONFIG_SMP=n?
Good point. It was based on the existing "first_cpu", but it's not a practice we should encourage.
Hmm, the implementation of these UP versions is wrong in corner cases, too. Obviously it doesn't currently matter the way they are used, but a nasty trap for the future.
Here's the addition, I've queued it for linux-next (which will next come out after the weekend).
diff -u b/include/linux/cpumask.h b/include/linux/cpumask.h --- b/include/linux/cpumask.h Fri Nov 07 00:15:12 2008 +1100 +++ b/include/linux/cpumask.h Fri Nov 07 22:28:33 2008 +1100 @@ -564,12 +564,36 @@ } #if NR_CPUS == 1 -/* Uniprocesor. */ -#define cpumask_first(src) ({ (void)(src); 0; }) -#define cpumask_next(n, src) ({ (void)(src); 1; }) -#define cpumask_next_zero(n, src) ({ (void)(src); 1; }) -#define cpumask_next_and(n, srcp, andp) ({ (void)(srcp), (void)(andp); 1; }) -#define cpumask_any_but(mask, cpu) ({ (void)(mask); (void)(cpu); 0; }) +/* Uniprocessor. Assume all masks are "1". */ +static inline unsigned int cpumask_first(const struct cpumask *srcp) +{ + return 0; +} + +/* Valid inputs for n are -1 and 0. */ +static inline unsigned int cpumask_next(int n, const struct cpumask *srcp) +{ + return n+1; +} + +static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp) +{ + return n+1; +} + +static inline unsigned int cpumask_next_and(int n, + const struct cpumask *srcp, + const struct cpumask *andp) +{ + return n+1; +} + +/* cpu must be a valid cpu, ie 0, so there's no other choice. */ +static inline unsigned int cpumask_any_but(const struct cpumask *mask, + unsigned int cpu) +{ + return 1; +} #define for_each_cpu(cpu, mask) \ for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask) diff -u b/lib/cpumask.c b/lib/cpumask.c --- b/lib/cpumask.c Fri Nov 07 00:15:12 2008 +1100 +++ b/lib/cpumask.c Fri Nov 07 22:28:33 2008 +1100 @@ -67,6 +67,7 @@ { unsigned int i; + cpumask_check(cpu); for_each_cpu(i, mask) if (i != cpu) break;
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