[PATCH] md: fix some locking and module refcounting issues with md's use of sysfs
1/ I really should be using the __ATTR macros for defining attributes, so
that the .owner field get set properly, otherwise modules can be removed
while sysfs files are open. This also involves some name changes of _show
routines.
2/ Always lock the mddev (against reconfiguration) for all sysfs attribute
access. This easily avoid certain races and is completely consistant with
other interfaces (ioctl and /proc/mdstat both always lock against
reconfiguration).
3/ raid5 attributes must check that the 'conf' structure actually exists
(the array could have been stopped while an attribute file was open).
4/ A missing 'kfree' from when the raid5_conf_t was converted to have a
kobject embedded, and then converted back again.
Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 51003b0..e2a4028 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1746,7 +1746,10 @@
raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
{
raid5_conf_t *conf = mddev_to_conf(mddev);
- return sprintf(page, "%d\n", conf->max_nr_stripes);
+ if (conf)
+ return sprintf(page, "%d\n", conf->max_nr_stripes);
+ else
+ return 0;
}
static ssize_t
@@ -1757,6 +1760,8 @@
int new;
if (len >= PAGE_SIZE)
return -EINVAL;
+ if (!conf)
+ return -ENODEV;
new = simple_strtoul(page, &end, 10);
if (!*page || (*end && *end != '\n') )
@@ -1777,23 +1782,23 @@
return len;
}
-static struct md_sysfs_entry raid5_stripecache_size = {
- .attr = {.name = "stripe_cache_size", .mode = S_IRUGO | S_IWUSR },
- .show = raid5_show_stripe_cache_size,
- .store = raid5_store_stripe_cache_size,
-};
+static struct md_sysfs_entry
+raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
+ raid5_show_stripe_cache_size,
+ raid5_store_stripe_cache_size);
static ssize_t
-raid5_show_stripe_cache_active(mddev_t *mddev, char *page)
+stripe_cache_active_show(mddev_t *mddev, char *page)
{
raid5_conf_t *conf = mddev_to_conf(mddev);
- return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
+ if (conf)
+ return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
+ else
+ return 0;
}
-static struct md_sysfs_entry raid5_stripecache_active = {
- .attr = {.name = "stripe_cache_active", .mode = S_IRUGO},
- .show = raid5_show_stripe_cache_active,
-};
+static struct md_sysfs_entry
+raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
static struct attribute *raid5_attrs[] = {
&raid5_stripecache_size.attr,
@@ -1981,6 +1986,7 @@
free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER);
blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
+ kfree(conf);
mddev->private = NULL;
return 0;
}