From 74390aa5567827add5058a3b26eff0ed06a629ba Mon Sep 17 00:00:00 2001 From: Kaixu Xia Date: Tue, 27 Jan 2015 17:55:12 +0800 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 Cc: Peter Zijlstra Cc: Paul Mackerras Link: http://lkml.kernel.org/r/1422352512-75150-1-git-send-email-xiakaixu@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- 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 7f2fbb8b5069..0969c9b67eec 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4420,7 +4420,7 @@ 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)) -- 2.20.1