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

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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
This commit is contained in:
Linus Torvalds
2013-09-12 11:28:24 -07:00
parent 02b9735c12 6a6f6e72ec
commit d5adf7e2db
1 changed files with 7 additions and 6 deletions
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13
drivers/xen/balloon.c
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@@ -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);