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Commit d5adf7e2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'stable/for-linus-3.12-rc0-tag-three' of... 

Merge tag 'stable/for-linus-3.12-rc0-tag-three' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull Xen balloon driver bug-fixes from Stefano Stabellini:
 - fix a preemption bug in xen/balloon.c;
 - remove an harmful BUG_ON in xen/balloon.c that can trigger in
   non-erroneous situations.

* tag 'stable/for-linus-3.12-rc0-tag-three' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/balloon: remove BUG_ON in increase_reservation
  xen/balloon: ensure preemption is disabled when using a scratch page
parents 02b9735c 6a6f6e72

drivers/xen/balloon.c

+7 −6
Original line number Diff line number Diff line
@@ -349,8 +349,6 @@ static enum bp_state increase_reservation(unsigned long nr_pages) 
		BUG_ON(page == NULL);



		pfn = page_to_pfn(page);

		BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) &&

		       phys_to_machine_mapping_valid(pfn));



		set_phys_to_machine(pfn, frame_list[i]);
@@ -380,6 +378,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 
	enum bp_state state = BP_DONE;

	unsigned long  pfn, i;

	struct page   *page;

	struct page   *scratch_page;

	int ret;

	struct xen_memory_reservation reservation = {

		.address_bits = 0,
@@ -399,6 +398,8 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 
	if (nr_pages > ARRAY_SIZE(frame_list))

		nr_pages = ARRAY_SIZE(frame_list);



	scratch_page = get_balloon_scratch_page();



	for (i = 0; i < nr_pages; i++) {

		page = alloc_page(gfp);

		if (page == NULL) {
@@ -416,7 +417,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 
		if (xen_pv_domain() && !PageHighMem(page)) {

			ret = HYPERVISOR_update_va_mapping(

				(unsigned long)__va(pfn << PAGE_SHIFT),

				pfn_pte(page_to_pfn(__get_cpu_var(balloon_scratch_page)),

				pfn_pte(page_to_pfn(scratch_page),

					PAGE_KERNEL_RO), 0);

			BUG_ON(ret);

		}
@@ -432,14 +433,14 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 
		pfn = mfn_to_pfn(frame_list[i]);

		if (!xen_feature(XENFEAT_auto_translated_physmap)) {

			unsigned long p;

			struct page *pg;

			pg = __get_cpu_var(balloon_scratch_page);

			p = page_to_pfn(pg);

			p = page_to_pfn(scratch_page);

			__set_phys_to_machine(pfn, pfn_to_mfn(p));

		}

		balloon_append(pfn_to_page(pfn));

	}



	put_balloon_scratch_page();



	set_xen_guest_handle(reservation.extent_start, frame_list);

	reservation.nr_extents   = nr_pages;

	ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);