From: Costa Shulyupin Date: Thu, 26 Sep 2024 09:26:22 +0000 (+0300) Subject: powerpc/xive: Use cpumask_intersects() X-Git-Tag: v6.13-rc1~98^2~14 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6da1cab4f5f8eb778fd61f0eb6ca5b0a011dd44d;p=thirdparty%2Fkernel%2Flinux.git powerpc/xive: Use cpumask_intersects() Replace `cpumask_any_and(a, b) >= nr_cpu_ids` with the more readable `!cpumask_intersects(a, b)`. Comparison between cpumask_any_and() and cpumask_intersects() The cpumask_any_and() function expands using FIND_FIRST_BIT(), resulting in a loop that iterates through each bit of the bitmask: for (idx = 0; idx * BITS_PER_LONG < sz; idx++) { val = (FETCH); if (val) { sz = min(idx * BITS_PER_LONG + __ffs(MUNGE(val)), sz); break; } } The cpumask_intersects() function expands using __bitmap_intersects(), resulting in that the first loop iterates through each long word of the bitmask, and the second through each bit within a long word: unsigned int k, lim = bits/BITS_PER_LONG; for (k = 0; k < lim; ++k) if (bitmap1[k] & bitmap2[k]) return true; if (bits % BITS_PER_LONG) if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) return true; Conclusion: cpumask_intersects() is at least as efficient as cpumask_any_and(), if not more so, as it typically performs fewer loops and comparisons. Signed-off-by: Costa Shulyupin Reviewed-by: Ming Lei Reviewed-by: Ritesh Harjani (IBM) Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20240926092623.399577-2-costa.shul@redhat.com --- diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c index fa01818c1972c..a6c388bdf5d08 100644 --- a/arch/powerpc/sysdev/xive/common.c +++ b/arch/powerpc/sysdev/xive/common.c @@ -726,7 +726,7 @@ static int xive_irq_set_affinity(struct irq_data *d, pr_debug("%s: irq %d/0x%x\n", __func__, d->irq, hw_irq); /* Is this valid ? */ - if (cpumask_any_and(cpumask, cpu_online_mask) >= nr_cpu_ids) + if (!cpumask_intersects(cpumask, cpu_online_mask)) return -EINVAL; /*