block: remove rcu_read_lock() from part_stat_lock() (8ab1d40a) · Commits · 戴 / test

block/genhd.c

+8 −3

Original line number	Diff line number	Diff line
		@@ -321,11 +321,12 @@ struct hd_struct disk_map_sector_rcu(struct gendisk disk, sector_t sector)
		struct hd_struct *part;
		int i;

		rcu_read_lock();
		ptbl = rcu_dereference(disk->part_tbl);

		part = rcu_dereference(ptbl->last_lookup);
		if (part && sector_in_part(part, sector) && hd_struct_try_get(part))
		return part;
		goto out_unlock;

		for (i = 1; i < ptbl->len; i++) {
		part = rcu_dereference(ptbl->part[i]);
		@@ -339,10 +340,14 @@ struct hd_struct disk_map_sector_rcu(struct gendisk disk, sector_t sector)
		if (!hd_struct_try_get(part))
		break;
		rcu_assign_pointer(ptbl->last_lookup, part);
		return part;
		goto out_unlock;
		}
		}
		return &disk->part0;

		part = &disk->part0;
		out_unlock:
		rcu_read_unlock();
		return part;
		}

		/**

+2 −2

Original line number	Diff line number	Diff line
		@@ -21,8 +21,8 @@ struct disk_stats {
		*
		* part_stat_read() can be called at any time.
		*/
		#define part_stat_lock() ({ rcu_read_lock(); get_cpu(); })
		#define part_stat_unlock() do { put_cpu(); rcu_read_unlock(); } while (0)
		#define part_stat_lock() preempt_disable()
		#define part_stat_unlock() preempt_enable()

		#define part_stat_get_cpu(part, field, cpu) \
		(per_cpu_ptr((part)->dkstats, (cpu))->field)