procfs: Kill the bkl in ioctl

There are no more users of procfs that implement the ioctl
callback. Drop the bkl from this path and warn on any use
of this callback.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: John Kacur <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Al Viro <[email protected]>

Author: fweisbec

fs/proc/inode.c

@@ -231,9 +231,9 @@ static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigne
 		if (rv == -ENOIOCTLCMD)
 			rv = -EINVAL;
 	} else if (ioctl) {
-		lock_kernel();
+		WARN_ONCE(1, "Procfs ioctl handlers must use unlocked_ioctl, "
+			  "%pf will be called without the Bkl held\n", ioctl);
 		rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
-		unlock_kernel();
 	}
 
 	pde_users_dec(pde);