Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[~andy/linux] / drivers / md / dm-table.c

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index f90069029aaeed02ab6f4f61814afc92d13db2f0..100368eb7991a50c57e473ea20bf4a8441e91ff0 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1212,6 +1212,41 @@ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
        return &t->targets[(KEYS_PER_NODE * n) + k];
 }
 
+static int count_device(struct dm_target *ti, struct dm_dev *dev,
+                       sector_t start, sector_t len, void *data)
+{
+       unsigned *num_devices = data;
+
+       (*num_devices)++;
+
+       return 0;
+}
+
+/*
+ * Check whether a table has no data devices attached using each
+ * target's iterate_devices method.
+ * Returns false if the result is unknown because a target doesn't
+ * support iterate_devices.
+ */
+bool dm_table_has_no_data_devices(struct dm_table *table)
+{
+       struct dm_target *uninitialized_var(ti);
+       unsigned i = 0, num_devices = 0;
+
+       while (i < dm_table_get_num_targets(table)) {
+               ti = dm_table_get_target(table, i++);
+
+               if (!ti->type->iterate_devices)
+                       return false;
+
+               ti->type->iterate_devices(ti, count_device, &num_devices);
+               if (num_devices)
+                       return false;
+       }
+
+       return true;
+}
+
 /*
  * Establish the new table's queue_limits and validate them.
  */
@@ -1354,17 +1389,25 @@ static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
        return q && blk_queue_nonrot(q);
 }
 
-static bool dm_table_is_nonrot(struct dm_table *t)
+static int device_is_not_random(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 && !blk_queue_add_random(q);
+}
+
+static bool dm_table_all_devices_attribute(struct dm_table *t,
+                                          iterate_devices_callout_fn func)
 {
        struct dm_target *ti;
        unsigned i = 0;
 
-       /* Ensure that all underlying device are non-rotational. */
        while (i < dm_table_get_num_targets(t)) {
                ti = dm_table_get_target(t, i++);
 
                if (!ti->type->iterate_devices ||
-                   !ti->type->iterate_devices(ti, device_is_nonrot, NULL))
+                   !ti->type->iterate_devices(ti, func, NULL))
                        return 0;
        }
 
@@ -1396,13 +1439,23 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
        if (!dm_table_discard_zeroes_data(t))
                q->limits.discard_zeroes_data = 0;
 
-       if (dm_table_is_nonrot(t))
+       /* Ensure that all underlying devices are non-rotational. */
+       if (dm_table_all_devices_attribute(t, device_is_nonrot))
                queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
        else
                queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
 
        dm_table_set_integrity(t);
 
+       /*
+        * 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
+        * have it set.
+        */
+       if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
+               queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
+
        /*
         * QUEUE_FLAG_STACKABLE must be set after all queue settings are
         * visible to other CPUs because, once the flag is set, incoming bios