Commit 80f22571 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

time: ntp: refactor do_adjtimex() 



Impact: cleanup, no functionality changed

do_adjtimex() is currently a monster function with a maze of
branches. Refactor the txc->modes setting aspects of it into
two new helper functions:

	process_adj_status()
	process_adjtimex_modes()

kernel/time/ntp.o:

   text	   data	    bss	    dec	    hex	filename
   2512	    114	    136	   2762	    aca	ntp.o.before
   2512	    114	    136	   2762	    aca	ntp.o.after

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 10dd31a7

kernel/time/ntp.c

+99 −83
Original line number Diff line number Diff line
@@ -332,68 +332,21 @@ static void notify_cmos_timer(void) 
static inline void notify_cmos_timer(void) { }

#endif



/*

 * adjtimex mainly allows reading (and writing, if superuser) of

 * kernel time-keeping variables. used by xntpd.

 */

int do_adjtimex(struct timex *txc)

{

	struct timespec ts;

	int result;



	/* Validate the data before disabling interrupts */

	if (txc->modes & ADJ_ADJTIME) {

		/* singleshot must not be used with any other mode bits */

		if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))

			return -EINVAL;

		if (!(txc->modes & ADJ_OFFSET_READONLY) &&

		    !capable(CAP_SYS_TIME))

			return -EPERM;

	} else {

		/* In order to modify anything, you gotta be super-user! */

		 if (txc->modes && !capable(CAP_SYS_TIME))

			return -EPERM;



/*

		 * if the quartz is off by more than 10% then

		 * something is VERY wrong!

 * Propagate a new txc->status value into the NTP state:

 */

		if (txc->modes & ADJ_TICK &&

		    (txc->tick <  900000/USER_HZ ||

		     txc->tick > 1100000/USER_HZ))

				return -EINVAL;



		if (txc->modes & ADJ_STATUS && time_state != TIME_OK)

			hrtimer_cancel(&leap_timer);

	}



	getnstimeofday(&ts);



	write_seqlock_irq(&xtime_lock);



	/* If there are input parameters, then process them */

	if (txc->modes & ADJ_ADJTIME) {

		long save_adjust = time_adjust;



		if (!(txc->modes & ADJ_OFFSET_READONLY)) {

			/* adjtime() is independent from ntp_adjtime() */

			time_adjust = txc->offset;

			ntp_update_frequency();

		}

		txc->offset = save_adjust;

		goto adj_done;

	}

	if (txc->modes) {

		long sec;

static inline void process_adj_status(struct timex *txc, struct timespec *ts)

{

	long now;



		if (txc->modes & ADJ_STATUS) {

			if ((time_status & STA_PLL) &&

			    !(txc->status & STA_PLL)) {

	if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {

		time_state = TIME_OK;

		time_status = STA_UNSYNC;

	}

	/* only set allowed bits */

	time_status &= STA_RONLY;



	/*

	 * If we turn on PLL adjustments then reset the

	 * reference time to current time.
@@ -406,22 +359,21 @@ int do_adjtimex(struct timex *txc) 
	switch (time_state) {

	case TIME_OK:

	start_timer:

				sec = ts.tv_sec;

		now = ts->tv_sec;

		if (time_status & STA_INS) {

			time_state = TIME_INS;

					sec += 86400 - sec % 86400;

					hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);

			now += 86400 - now % 86400;

			hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);

		} else if (time_status & STA_DEL) {

			time_state = TIME_DEL;

					sec += 86400 - (sec + 1) % 86400;

					hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);

			now += 86400 - (now + 1) % 86400;

			hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);

		}

		break;

	case TIME_INS:

	case TIME_DEL:

		time_state = TIME_OK;

		goto start_timer;

				break;

	case TIME_WAIT:

		if (!(time_status & (STA_INS | STA_DEL)))

			time_state = TIME_OK;
@@ -431,6 +383,14 @@ int do_adjtimex(struct timex *txc) 
		break;

	}

}

/*

 * Called with the xtime lock held, so we can access and modify

 * all the global NTP state:

 */

static inline void process_adjtimex_modes(struct timex *txc, struct timespec *ts)

{

	if (txc->modes & ADJ_STATUS)

		process_adj_status(txc, ts);



	if (txc->modes & ADJ_NANO)

		time_status |= STA_NANO;
@@ -468,6 +428,62 @@ int do_adjtimex(struct timex *txc) 
		ntp_update_frequency();

}



/*

 * adjtimex mainly allows reading (and writing, if superuser) of

 * kernel time-keeping variables. used by xntpd.

 */

int do_adjtimex(struct timex *txc)

{

	struct timespec ts;

	int result;



	/* Validate the data before disabling interrupts */

	if (txc->modes & ADJ_ADJTIME) {

		/* singleshot must not be used with any other mode bits */

		if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))

			return -EINVAL;

		if (!(txc->modes & ADJ_OFFSET_READONLY) &&

		    !capable(CAP_SYS_TIME))

			return -EPERM;

	} else {

		/* In order to modify anything, you gotta be super-user! */

		 if (txc->modes && !capable(CAP_SYS_TIME))

			return -EPERM;



		/*

		 * if the quartz is off by more than 10% then

		 * something is VERY wrong!

		 */

		if (txc->modes & ADJ_TICK &&

		    (txc->tick <  900000/USER_HZ ||

		     txc->tick > 1100000/USER_HZ))

				return -EINVAL;



		if (txc->modes & ADJ_STATUS && time_state != TIME_OK)

			hrtimer_cancel(&leap_timer);

	}



	getnstimeofday(&ts);



	write_seqlock_irq(&xtime_lock);



	/* If there are input parameters, then process them */

	if (txc->modes & ADJ_ADJTIME) {

		long save_adjust = time_adjust;



		if (!(txc->modes & ADJ_OFFSET_READONLY)) {

			/* adjtime() is independent from ntp_adjtime() */

			time_adjust = txc->offset;

			ntp_update_frequency();

		}

		txc->offset = save_adjust;

		goto adj_done;

	}



	/* If there are input parameters, then process them: */

	if (txc->modes)

		process_adjtimex_modes(txc, &ts);



	txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,

				  NTP_SCALE_SHIFT);

	if (!(time_status & STA_NANO))

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