Merge tag 'drm-qemu-20161121' of git://git.kraxel.org/linux into drm-next

drm/virtio: fix busid in a different way, allocate more vbufs.
drm/qxl: various bugfixes and cleanups,

* tag 'drm-qemu-20161121' of git://git.kraxel.org/linux: (224 commits)
  drm/virtio: allocate some extra bufs
  qxl: Allow resolution which are not multiple of 8
  qxl: Don't notify userspace when monitors config is unchanged
  qxl: Remove qxl_bo_init() return value
  qxl: Call qxl_gem_{init, fini}
  qxl: Add missing '\n' to qxl_io_log() call
  qxl: Remove unused prototype
  qxl: Mark some internal functions as static
  Revert "drm: virtio: reinstate drm_virtio_set_busid()"
  drm/virtio: fix busid regression
  drm: re-export drm_dev_set_unique
  Linux 4.9-rc5
  gp8psk: Fix DVB frontend attach
  gp8psk: fix gp8psk_usb_in_op() logic
  dvb-usb: move data_mutex to struct dvb_usb_device
  iio: maxim_thermocouple: detect invalid storage size in read()
  aoe: fix crash in page count manipulation
  lightnvm: invalid offset calculation for lba_shift
  Kbuild: enable -Wmaybe-uninitialized warnings by default
  pcmcia: fix return value of soc_pcmcia_regulator_set
  ...

1 files changed, 66 insertions, 0 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ec49d9ef1eef..418bf01a50ed 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1826,11 +1826,17 @@ static void return_unused_surplus_pages(struct hstate *h,
  * is not the case is if a reserve map was changed between calls.  It
  * is the responsibility of the caller to notice the difference and
  * take appropriate action.
+ *
+ * vma_add_reservation is used in error paths where a reservation must
+ * be restored when a newly allocated huge page must be freed.  It is
+ * to be called after calling vma_needs_reservation to determine if a
+ * reservation exists.
  */
 enum vma_resv_mode {
 	VMA_NEEDS_RESV,
 	VMA_COMMIT_RESV,
 	VMA_END_RESV,
+	VMA_ADD_RESV,
 };
 static long __vma_reservation_common(struct hstate *h,
 				struct vm_area_struct *vma, unsigned long addr,
@@ -1856,6 +1862,14 @@ static long __vma_reservation_common(struct hstate *h,
 		region_abort(resv, idx, idx + 1);
 		ret = 0;
 		break;
+	case VMA_ADD_RESV:
+		if (vma->vm_flags & VM_MAYSHARE)
+			ret = region_add(resv, idx, idx + 1);
+		else {
+			region_abort(resv, idx, idx + 1);
+			ret = region_del(resv, idx, idx + 1);
+		}
+		break;
 	default:
 		BUG();
 	}
@@ -1903,6 +1917,56 @@ static void vma_end_reservation(struct hstate *h,
 	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
 }
 
+static long vma_add_reservation(struct hstate *h,
+			struct vm_area_struct *vma, unsigned long addr)
+{
+	return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
+}
+
+/*
+ * This routine is called to restore a reservation on error paths.  In the
+ * specific error paths, a huge page was allocated (via alloc_huge_page)
+ * and is about to be freed.  If a reservation for the page existed,
+ * alloc_huge_page would have consumed the reservation and set PagePrivate
+ * in the newly allocated page.  When the page is freed via free_huge_page,
+ * the global reservation count will be incremented if PagePrivate is set.
+ * However, free_huge_page can not adjust the reserve map.  Adjust the
+ * reserve map here to be consistent with global reserve count adjustments
+ * to be made by free_huge_page.
+ */
+static void restore_reserve_on_error(struct hstate *h,
+			struct vm_area_struct *vma, unsigned long address,
+			struct page *page)
+{
+	if (unlikely(PagePrivate(page))) {
+		long rc = vma_needs_reservation(h, vma, address);
+
+		if (unlikely(rc < 0)) {
+			/*
+			 * Rare out of memory condition in reserve map
+			 * manipulation.  Clear PagePrivate so that
+			 * global reserve count will not be incremented
+			 * by free_huge_page.  This will make it appear
+			 * as though the reservation for this page was
+			 * consumed.  This may prevent the task from
+			 * faulting in the page at a later time.  This
+			 * is better than inconsistent global huge page
+			 * accounting of reserve counts.
+			 */
+			ClearPagePrivate(page);
+		} else if (rc) {
+			rc = vma_add_reservation(h, vma, address);
+			if (unlikely(rc < 0))
+				/*
+				 * See above comment about rare out of
+				 * memory condition.
+				 */
+				ClearPagePrivate(page);
+		} else
+			vma_end_reservation(h, vma, address);
+	}
+}
+
 struct page *alloc_huge_page(struct vm_area_struct *vma,
 				    unsigned long addr, int avoid_reserve)
 {
@@ -3498,6 +3562,7 @@ retry_avoidcopy:
 	spin_unlock(ptl);
 	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
 out_release_all:
+	restore_reserve_on_error(h, vma, address, new_page);
 	put_page(new_page);
 out_release_old:
 	put_page(old_page);
@@ -3680,6 +3745,7 @@ backout:
 	spin_unlock(ptl);
 backout_unlocked:
 	unlock_page(page);
+	restore_reserve_on_error(h, vma, address, page);
 	put_page(page);
 	goto out;
 }