Commit 74390aa5 authored Jan 27, 2015 by Kaixu Xia Committed by Arnaldo Carvalho de Melo Feb 13, 2015

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@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Link: http://lkml.kernel.org/r/1422352512-75150-1-git-send-email-xiakaixu@huawei.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 3a03005f

kernel/events/core.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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))

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