tracefs/eventfs: Use list_for_each_srcu() in dcache_dir_open_wrapper()

The eventfs files list is protected by SRCU. In earlier iterations it was
protected with just RCU, but because it needed to also call sleepable
code, it had to be switch to SRCU. The dcache_dir_open_wrapper()
list_for_each_rcu() was missed and did not get converted over to
list_for_each_srcu(). That needs to be fixed.

Link: https://lore.kernel.org/linux-trace-kernel/[email protected]/
Link: https://lore.kernel.org/linux-trace-kernel/[email protected]

Cc: Mark Rutland <[email protected]>
Cc: Ajay Kaher <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Reported-by: Masami Hiramatsu (Google) <[email protected]>
Fixes: 6394044 ("eventfs: Implement eventfs lookup, read, open functions")
Signed-off-by: Steven Rostedt (Google) <[email protected]>

Author: rostedt

fs/tracefs/event_inode.c

@@ -452,7 +452,8 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
 
 	ei = ti->private;
 	idx = srcu_read_lock(&eventfs_srcu);
-	list_for_each_entry_rcu(ef, &ei->e_top_files, list) {
+	list_for_each_entry_srcu(ef, &ei->e_top_files, list,
+				 srcu_read_lock_held(&eventfs_srcu)) {
 		create_dentry(ef, dentry, false);
 	}
 	srcu_read_unlock(&eventfs_srcu, idx);