md/md-llbitmap: fix percpu_ref not resurrected on suspend timeout

When llbitmap_suspend_timeout() times out waiting for percpu_ref to
become zero, it returns -ETIMEDOUT without resurrecting the percpu_ref.
The caller (md_llbitmap_daemon_fn) then continues to the next page
without calling llbitmap_resume(), leaving the percpu_ref in a killed
state permanently.

Fix this by resurrecting the percpu_ref before returning the error,
ensuring the page control structure remains usable for subsequent
operations.

Link: https://lore.kernel.org/linux-raid/[email protected]
Fixes: 5ab829f ("md/md-llbitmap: introduce new lockless bitmap")
Signed-off-by: Yu Kuai <[email protected]>
Reviewed-by: Li Nan <[email protected]>

Author: hailan94

drivers/md/md-llbitmap.c

@@ -712,8 +712,10 @@ static int llbitmap_suspend_timeout(struct llbitmap *llbitmap, int page_idx)
 	percpu_ref_kill(&pctl->active);
 
 	if (!wait_event_timeout(pctl->wait, percpu_ref_is_zero(&pctl->active),
-			llbitmap->mddev->bitmap_info.daemon_sleep * HZ))
+			llbitmap->mddev->bitmap_info.daemon_sleep * HZ)) {
+		percpu_ref_resurrect(&pctl->active);
 		return -ETIMEDOUT;
+	}
 
 	return 0;
 }