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Date: Tue, 27 Jan 2015 17:55:12 +0800 From: Kaixu Xia <xiakaixu@...wei.com> To: <a.p.zijlstra@...llo.nl>, <paulus@...ba.org>, <mingo@...hat.com>, <acme@...nel.org> CC: <linux-kernel@...r.kernel.org>, <xiakaixu@...wei.com>, <kaixu.xia@...aro.org> Subject: [PATCH] perf: remove the extra validity check on nr_pages The function is_power_of_2() also do the check on nr_pages, so the first check performed is unnecessary. On the other hand, the key point is to ensure @nr_pages is a power-of-two number and mostly @nr_pages is a nonzero value, so in the most cases, the function is_power_of_2() will be called. Signed-off-by: Kaixu Xia <xiakaixu@...wei.com> --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 882f835..abb57c2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4268,7 +4268,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) * If we have rb pages ensure they're a power-of-two number, so we * can do bitmasks instead of modulo. */ - if (nr_pages != 0 && !is_power_of_2(nr_pages)) + if (!is_power_of_2(nr_pages)) return -EINVAL; if (vma_size != PAGE_SIZE * (1 + nr_pages)) -- 1.8.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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