Merge tag 'block-5.15-2021-10-22' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "Fix for the cgroup code not ussing irq safe stats updates, and one fix
  for an error handling condition in add_partition()"

* tag 'block-5.15-2021-10-22' of git://git.kernel.dk/linux-block:
  block: fix incorrect references to disk objects
  blk-cgroup: blk_cgroup_bio_start() should use irq-safe operations on blkg->iostat_cpu

Author: torvalds

block/blk-cgroup.c

@@ -1897,10 +1897,11 @@ void blk_cgroup_bio_start(struct bio *bio)
 {
 	int rwd = blk_cgroup_io_type(bio), cpu;
 	struct blkg_iostat_set *bis;
+	unsigned long flags;
 
 	cpu = get_cpu();
 	bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu);
-	u64_stats_update_begin(&bis->sync);
+	flags = u64_stats_update_begin_irqsave(&bis->sync);
 
 	/*
 	 * If the bio is flagged with BIO_CGROUP_ACCT it means this is a split
@@ -1912,7 +1913,7 @@ void blk_cgroup_bio_start(struct bio *bio)
 	}
 	bis->cur.ios[rwd]++;
 
-	u64_stats_update_end(&bis->sync);
+	u64_stats_update_end_irqrestore(&bis->sync, flags);
 	if (cgroup_subsys_on_dfl(io_cgrp_subsys))
 		cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu);
 	put_cpu();

block/partitions/core.c

@@ -423,6 +423,7 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
 	device_del(pdev);
 out_put:
 	put_device(pdev);
+	return ERR_PTR(err);
 out_put_disk:
 	put_disk(disk);
 	return ERR_PTR(err);