1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index ba9481f1bf3c..cde3b49b2a91 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1844,6 +1844,36 @@ static bool dm_table_supports_secure_erase(struct dm_table *t)
         return true;
 }
 
+static int device_requires_stable_pages(struct dm_target *ti,
+                                        struct dm_dev *dev, sector_t start,
+                                        sector_t len, void *data)
+{
+        struct request_queue *q = bdev_get_queue(dev->bdev);
+
+        return q && bdi_cap_stable_pages_required(q->backing_dev_info);
+}
+
+/*
+ * If any underlying device requires stable pages, a table must require
+ * them as well.  Only targets that support iterate_devices are considered:
+ * don't want error, zero, etc to require stable pages.
+ */
+static bool dm_table_requires_stable_pages(struct dm_table *t)
+{
+        struct dm_target *ti;
+        unsigned i;
+
+        for (i = 0; i < dm_table_get_num_targets(t); i++) {
+                ti = dm_table_get_target(t, i);
+
+                if (ti->type->iterate_devices &&
+                    ti->type->iterate_devices(ti, device_requires_stable_pages, NULL))
+                        return true;
+        }
+
+        return false;
+}
+
 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
                                struct queue_limits *limits)
 {
@@ -1897,6 +1927,15 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
         dm_table_verify_integrity(t);
 
         /*
+         * Some devices don't use blk_integrity but still want stable pages
+         * because they do their own checksumming.
+         */
+        if (dm_table_requires_stable_pages(t))
+                q->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
+        else
+                q->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
+
+        /*
          * Determine whether or not this queue's I/O timings contribute
          * to the entropy pool, Only request-based targets use this.
          * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not