!1349 [sync] PR-1294: dm stats: check for and propagate alloc_percpu failure

Merge Pull Request from: @openeuler-sync-bot 
 

Origin pull request: 
https://gitee.com/openeuler/kernel/pulls/1294 
 
PR sync from: Li Lingfeng <lilingfeng3@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/JMXBT7PXZENQ6R7L2JBRQLXB3NS26AY2/ 
 
 
Link:https://gitee.com/openeuler/kernel/pulls/1349 

Reviewed-by: Yu Kuai <yukuai3@huawei.com> 
Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com> 
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> 

drivers/md/dm-stats.c

@@ -188,7 +188,7 @@ static int dm_stat_in_flight(struct dm_stat_shared *shared)
 	       atomic_read(&shared->in_flight[WRITE]);
 }
 
-void dm_stats_init(struct dm_stats *stats)
+int dm_stats_init(struct dm_stats *stats)
 {
 	int cpu;
 	struct dm_stats_last_position *last;
@@ -196,11 +196,16 @@ void dm_stats_init(struct dm_stats *stats)
 	mutex_init(&stats->mutex);
 	INIT_LIST_HEAD(&stats->list);
 	stats->last = alloc_percpu(struct dm_stats_last_position);
+	if (!stats->last)
+		return -ENOMEM;
+
 	for_each_possible_cpu(cpu) {
 		last = per_cpu_ptr(stats->last, cpu);
 		last->last_sector = (sector_t)ULLONG_MAX;
 		last->last_rw = UINT_MAX;
 	}
+
+	return 0;
 }
 
 void dm_stats_cleanup(struct dm_stats *stats)

drivers/md/dm-stats.h

@@ -22,7 +22,7 @@ struct dm_stats_aux {
 	unsigned long long duration_ns;
 };
 
-void dm_stats_init(struct dm_stats *st);
+int dm_stats_init(struct dm_stats *st);
 void dm_stats_cleanup(struct dm_stats *st);
 
 struct mapped_device;

drivers/md/dm.c

@@ -1899,7 +1899,9 @@ static struct mapped_device *alloc_dev(int minor)
 	if (!md->bdev)
 		goto bad;
 
-	dm_stats_init(&md->stats);
+	r = dm_stats_init(&md->stats);
+	if (r < 0)
+		goto bad;
 
 	/* Populate the mapping, nobody knows we exist yet */
 	spin_lock(&_minor_lock);