[PATCH] schedule removal of FUTEX_FD

Apparently FUTEX_FD is unfixably racy and nothing uses it (or if it does, it
shouldn't).

Add a warning printk, give any remaining users six months to migrate off it.

Cc: Ulrich Drepper <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Acked-by: Thomas Gleixner <[e-mail]>
Cc: Rusty Russell <[e-mail]>
Cc: Alan Cox <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

kernel/futex.c

···
 	struct futex_q *q;
 	struct file *filp;
 	int ret, err;
+	static unsigned long printk_interval;
+
+	if (printk_timed_ratelimit(&printk_interval, 60 * 60 * 1000)) {
+		printk(KERN_WARNING "Process `%s' used FUTEX_FD, which "
+		    	"will be removed from the kernel in June 2007\n",
+			current->comm);
+	}
 
 	ret = -EINVAL;
 	if (!valid_signal(signal))