Commit 7730d865 authored Mar 25, 2009 by Peter Zijlstra Committed by Ingo Molnar Apr 06, 2009

perf_counter: allow and require one-page mmap on counting counters



A brainfart stopped single page mmap()s working. The rest of the code
should be perfectly fine with not having any data pages.

Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Orig-LKML-Reference: <1237981712.7972.812.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 00f0ad73

kernel/perf_counter.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -1369,7 +1369,11 @@ static int perf_mmap(struct file file, struct vm_area_struct vma)
		vma_size = vma->vm_end - vma->vm_start;
		nr_pages = (vma_size / PAGE_SIZE) - 1;

		if (nr_pages == 0 \|\| !is_power_of_2(nr_pages))
		/*
		* If we have data 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))
		return -EINVAL;

		if (vma_size != PAGE_SIZE * (1 + nr_pages))