From 750f199ee8b578062341e6ddfe36c59ac8ff2dcb Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 30 Sep 2014 08:53:05 +1000 Subject: [PATCH] md: mark some attributes as pre-alloc Since __ATTR_PREALLOC was introduced in v3.19-rc1~78^2~18 it can now be used by md. This ensure that writing to these sysfs attributes will never block due to a memory allocation. Such blocking could become a deadlock if mdmon is trying to reconfigure an array after a failure prior to re-enabling writes. Signed-off-by: NeilBrown --- drivers/md/md.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index c8d2bac4e28b..cadf9cc02b25 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -2555,7 +2555,7 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len) return err ? err : len; } static struct rdev_sysfs_entry rdev_state = -__ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store); +__ATTR_PREALLOC(state, S_IRUGO|S_IWUSR, state_show, state_store); static ssize_t errors_show(struct md_rdev *rdev, char *page) @@ -3638,7 +3638,8 @@ resync_start_store(struct mddev *mddev, const char *buf, size_t len) return err ?: len; } static struct md_sysfs_entry md_resync_start = -__ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store); +__ATTR_PREALLOC(resync_start, S_IRUGO|S_IWUSR, + resync_start_show, resync_start_store); /* * The array state can be: @@ -3851,7 +3852,7 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len) return err ?: len; } static struct md_sysfs_entry md_array_state = -__ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store); +__ATTR_PREALLOC(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store); static ssize_t max_corrected_read_errors_show(struct mddev *mddev, char *page) { @@ -4101,7 +4102,7 @@ out_unlock: } static struct md_sysfs_entry md_metadata = -__ATTR(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store); +__ATTR_PREALLOC(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store); static ssize_t action_show(struct mddev *mddev, char *page) @@ -4189,7 +4190,7 @@ action_store(struct mddev *mddev, const char *page, size_t len) } static struct md_sysfs_entry md_scan_mode = -__ATTR(sync_action, S_IRUGO|S_IWUSR, action_show, action_store); +__ATTR_PREALLOC(sync_action, S_IRUGO|S_IWUSR, action_show, action_store); static ssize_t last_sync_action_show(struct mddev *mddev, char *page) @@ -4335,7 +4336,8 @@ sync_completed_show(struct mddev *mddev, char *page) return sprintf(page, "%llu / %llu\n", resync, max_sectors); } -static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed); +static struct md_sysfs_entry md_sync_completed = + __ATTR_PREALLOC(sync_completed, S_IRUGO, sync_completed_show, NULL); static ssize_t min_sync_show(struct mddev *mddev, char *page)