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cpumask: Use all NR_CPUS bits unless CONFIG_CPUMASK_OFFSTACK

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Impact: futureproof as we convert more code to new APIs

The old cpumask operators treat all NR_CPUS bits as relevent, the new
ones use nr_cpumask_bits.  For large NR_CPUS and small nr_cpu_ids, this
makes a difference.

However, mixing the two can cause problems with undefined bits.  An
arch which sets CONFIG_CPUMASK_OFFSTACK should have converted across
to the new operators, so it's safe in that case.

(Thanks to Stephen Rothwell for bisecting the initial unused-bits bug,
and Mike Travis for this solution).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Mike Travis <travis@sgi.com>
This commit is contained in:
Rusty Russell 2008-12-13 21:20:28 +10:30
parent f0b848ce6f
commit 7be7585393
1 changed files with 8 additions and 5 deletions
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13
include/linux/cpumask.h
View file

@ -510,9 +510,6 @@ extern cpumask_t cpu_active_map;
[BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \
}
/* This produces more efficient code. */
#define nr_cpumask_bits NR_CPUS
#else /* NR_CPUS > BITS_PER_LONG */
#define CPU_BITS_ALL \
@ -520,10 +517,16 @@ extern cpumask_t cpu_active_map;
[0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL, \
[BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \
}
#define nr_cpumask_bits nr_cpu_ids
#endif /* NR_CPUS > BITS_PER_LONG */
#ifdef CONFIG_CPUMASK_OFFSTACK
/* Assuming NR_CPUS is huge, a runtime limit is more efficient. Also,
* not all bits may be allocated. */
#define nr_cpumask_bits nr_cpu_ids
#else
#define nr_cpumask_bits NR_CPUS
#endif
/* verify cpu argument to cpumask_* operators */
static inline unsigned int cpumask_check(unsigned int cpu)
{