sched/deadline: Use proc_douintvec_minmax() limit minimum value

sysctl_sched_dl_period_max and sysctl_sched_dl_period_min are unsigned
integer, but proc_dointvec() wouldn't return error even if we set a
negative number.

Use proc_douintvec_minmax() instead of proc_dointvec(). Add extra1 for
sysctl_sched_dl_period_max and extra2 for sysctl_sched_dl_period_min.

It's just an optimization for match data and proc_handler in struct
ctl_table. The 'if (period < min || period > max)' in __checkparam_dl()
will work fine even if there hasn't this patch.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Link: https://lore.kernel.org/r/20220607101807.249965-1-yajun.deng@linux.dev

kernel/sched/deadline.c

@@ -30,14 +30,16 @@ static struct ctl_table sched_dl_sysctls[] = {
 		.data           = &sysctl_sched_dl_period_max,
 		.maxlen         = sizeof(unsigned int),
 		.mode           = 0644,
-		.proc_handler   = proc_dointvec,
+		.proc_handler   = proc_douintvec_minmax,
+		.extra1         = (void *)&sysctl_sched_dl_period_min,
 	},
 	{
 		.procname       = "sched_deadline_period_min_us",
 		.data           = &sysctl_sched_dl_period_min,
 		.maxlen         = sizeof(unsigned int),
 		.mode           = 0644,
-		.proc_handler   = proc_dointvec,
+		.proc_handler   = proc_douintvec_minmax,
+		.extra2         = (void *)&sysctl_sched_dl_period_max,
 	},
 	{}
 };