md/linear: use call_rcu to free obsolete 'conf' structures. (495d3573) · Commits · 戴 / test

drivers/md/linear.c

+13 −8

Original line number	Diff line number	Diff line
		@@ -223,6 +223,12 @@ static int linear_run (mddev_t *mddev)
		return 0;
		}

		static void free_conf(struct rcu_head *head)
		{
		linear_conf_t *conf = container_of(head, linear_conf_t, rcu);
		kfree(conf);
		}

		static int linear_add(mddev_t mddev, mdk_rdev_t rdev)
		{
		/* Adding a drive to a linear array allows the array to grow.
		@@ -233,7 +239,7 @@ static int linear_add(mddev_t mddev, mdk_rdev_t rdev)
		* The current one is never freed until the array is stopped.
		* This avoids races.
		*/
		linear_conf_t *newconf;
		linear_conf_t newconf, oldconf;

		if (rdev->saved_raid_disk != mddev->raid_disks)
		return -EINVAL;
		@@ -245,11 +251,12 @@ static int linear_add(mddev_t mddev, mdk_rdev_t rdev)
		if (!newconf)
		return -ENOMEM;

		newconf->prev = mddev->private;
		oldconf = rcu_dereference(mddev->private);
		mddev->raid_disks++;
		rcu_assign_pointer(mddev->private, newconf);
		md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
		set_capacity(mddev->gendisk, mddev->array_sectors);
		call_rcu(&oldconf->rcu, free_conf);
		return 0;
		}

		@@ -261,14 +268,12 @@ static int linear_stop (mddev_t *mddev)
		* We do not require rcu protection here since
		* we hold reconfig_mutex for both linear_add and
		* linear_stop, so they cannot race.
		* We should make sure any old 'conf's are properly
		* freed though.
		*/

		rcu_barrier();
		blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
		do {
		linear_conf_t *t = conf->prev;
		kfree(conf);
		conf = t;
		} while (conf);

		return 0;
		}

+1 −1

Original line number	Diff line number	Diff line
		@@ -10,9 +10,9 @@ typedef struct dev_info dev_info_t;

		struct linear_private_data
		{
		struct linear_private_data prev; / earlier version */
		sector_t array_sectors;
		dev_info_t disks[0];
		struct rcu_head rcu;
		};