Commit 3bcfeaf9 authored Oct 20, 2011 by David Vrabel Committed by Jens Axboe Oct 20, 2011

block: initialize the bounce pool if high memory may be added later



init_emergency_pool() does not create the page pool for bouncing block
requests if the current count of high pages is zero.  If high memory
may be added later (either via memory hotplug or a balloon driver in a
virtualized system) then a oops occurs if a request with a high page
need bouncing because the pool does not exist.

So, always create the pool if memory hotplug is enabled and change the
test so it's valid even if all high pages are currently in the balloon
(the balloon drivers adjust totalhigh_pages but not max_pfn).

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent c9a929dd

mm/bounce.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -14,6 +14,7 @@
		#include <linux/init.h>
		#include <linux/hash.h>
		#include <linux/highmem.h>
		#include <linux/bootmem.h>
		#include <asm/tlbflush.h>

		#include <trace/events/block.h>
		@@ -26,12 +27,10 @@ static mempool_t page_pool, isa_page_pool;
		#ifdef CONFIG_HIGHMEM
		static __init int init_emergency_pool(void)
		{
		struct sysinfo i;
		si_meminfo(&i);
		si_swapinfo(&i);

		if (!i.totalhigh)
		#ifndef CONFIG_MEMORY_HOTPLUG
		if (max_pfn <= max_low_pfn)
		return 0;
		#endif

		page_pool = mempool_create_page_pool(POOL_SIZE, 0);
		BUG_ON(!page_pool);

Admin message