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Commit 3c0ee63a authored by NeilBrown's avatar NeilBrown
Browse files

md: use sysfs_notify_dirent to notify changes to md/dev-xxx/state 



The 'state' file for a device reports, for example, when the device
has failed.  Changes should be reported to userspace ASAP without
the possibility of blocking on low-memory.  sysfs_notify does
have that possibility (as it takes a mutex which can be held
across a kmalloc) so use sysfs_notify_dirent instead.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent b62b7590

drivers/md/md.c

+12 −9
Original line number Diff line number Diff line
@@ -1462,6 +1462,8 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev) 
		kobject_del(&rdev->kobj);

		goto fail;

	}

	rdev->sysfs_state = sysfs_get_dirent(rdev->kobj.sd, "state");



	list_add_rcu(&rdev->same_set, &mddev->disks);

	bd_claim_by_disk(rdev->bdev, rdev->bdev->bd_holder, mddev->gendisk);

	return 0;
@@ -1491,7 +1493,8 @@ static void unbind_rdev_from_array(mdk_rdev_t * rdev) 
	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));

	rdev->mddev = NULL;

	sysfs_remove_link(&rdev->kobj, "block");



	sysfs_put(rdev->sysfs_state);

	rdev->sysfs_state = NULL;

	/* We need to delay this, otherwise we can deadlock when

	 * writing to 'remove' to "dev/state".  We also need

	 * to delay it due to rcu usage.
@@ -1926,8 +1929,8 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len) 


		err = 0;

	}

	if (!err)

		sysfs_notify(&rdev->kobj, NULL, "state");

	if (!err && rdev->sysfs_state)

		sysfs_notify_dirent(rdev->sysfs_state);

	return err ? err : len;

}

static struct rdev_sysfs_entry rdev_state =
@@ -2022,7 +2025,7 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len) 
			rdev->raid_disk = -1;

			return err;

		} else

			sysfs_notify(&rdev->kobj, NULL, "state");

			sysfs_notify_dirent(rdev->sysfs_state);

		sprintf(nm, "rd%d", rdev->raid_disk);

		if (sysfs_create_link(&rdev->mddev->kobj, &rdev->kobj, nm))

			printk(KERN_WARNING
@@ -2039,7 +2042,7 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len) 
		clear_bit(Faulty, &rdev->flags);

		clear_bit(WriteMostly, &rdev->flags);

		set_bit(In_sync, &rdev->flags);

		sysfs_notify(&rdev->kobj, NULL, "state");

		sysfs_notify_dirent(rdev->sysfs_state);

	}

	return len;

}
@@ -3583,7 +3586,7 @@ static int do_md_run(mddev_t * mddev) 
				return -EINVAL;

			}

		}

		sysfs_notify(&rdev->kobj, NULL, "state");

		sysfs_notify_dirent(rdev->sysfs_state);

	}



	md_probe(mddev->unit, NULL, NULL);
@@ -4302,7 +4305,7 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info) 
		if (err)

			export_rdev(rdev);

		else

			sysfs_notify(&rdev->kobj, NULL, "state");

			sysfs_notify_dirent(rdev->sysfs_state);



		md_update_sb(mddev, 1);

		if (mddev->degraded)
@@ -6113,7 +6116,7 @@ void md_check_recovery(mddev_t *mddev) 


		rdev_for_each(rdev, rtmp, mddev)

			if (test_and_clear_bit(StateChanged, &rdev->flags))

				sysfs_notify(&rdev->kobj, NULL, "state");

				sysfs_notify_dirent(rdev->sysfs_state);





		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
@@ -6223,7 +6226,7 @@ void md_check_recovery(mddev_t *mddev) 


void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev)

{

	sysfs_notify(&rdev->kobj, NULL, "state");

	sysfs_notify_dirent(rdev->sysfs_state);

	wait_event_timeout(rdev->blocked_wait,

			   !test_bit(Blocked, &rdev->flags),

			   msecs_to_jiffies(5000));

include/linux/raid/md_k.h

+3 −0
Original line number Diff line number Diff line
@@ -115,6 +115,9 @@ struct mdk_rdev_s 
					   * in superblock.

					   */

	struct work_struct del_work;	/* used for delayed sysfs removal */



	struct sysfs_dirent *sysfs_state; /* handle for 'state'

					   * sysfs entry */

};



struct mddev_s