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authorJohn Stultz <john.stultz@linaro.org>2011-04-28 15:58:11 -0400
committerJohn Stultz <john.stultz@linaro.org>2011-04-28 16:39:17 -0400
commit180bf812ceaf01eb8ac69b86f3be0bd57f697668 (patch)
treee61166d1267a15115dc602875ec03835afc1afe7 /kernel/time
parent9a7adcf5c6dea63d2e47e6f6d2f7a6c9f48b9337 (diff)
timers: Improve alarmtimer comments and minor fixes
This patch addresses a number of minor comment improvements and other minor issues from Thomas' review of the alarmtimers code. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/alarmtimer.c67
1 files changed, 27 insertions, 40 deletions
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 4058ad79d55f..bed98004ae1a 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -26,7 +26,15 @@
26#include <linux/workqueue.h> 26#include <linux/workqueue.h>
27#include <linux/freezer.h> 27#include <linux/freezer.h>
28 28
29 29/**
30 * struct alarm_base - Alarm timer bases
31 * @lock: Lock for syncrhonized access to the base
32 * @timerqueue: Timerqueue head managing the list of events
33 * @timer: hrtimer used to schedule events while running
34 * @gettime: Function to read the time correlating to the base
35 * @base_clockid: clockid for the base
36 * @irqwork Delayed work structure for expiring timers
37 */
30static struct alarm_base { 38static struct alarm_base {
31 spinlock_t lock; 39 spinlock_t lock;
32 struct timerqueue_head timerqueue; 40 struct timerqueue_head timerqueue;
@@ -36,18 +44,16 @@ static struct alarm_base {
36 struct work_struct irqwork; 44 struct work_struct irqwork;
37} alarm_bases[ALARM_NUMTYPE]; 45} alarm_bases[ALARM_NUMTYPE];
38 46
47/* rtc timer and device for setting alarm wakeups at suspend */
39static struct rtc_timer rtctimer; 48static struct rtc_timer rtctimer;
40static struct rtc_device *rtcdev; 49static struct rtc_device *rtcdev;
41 50
51/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
42static ktime_t freezer_delta; 52static ktime_t freezer_delta;
43static DEFINE_SPINLOCK(freezer_delta_lock); 53static DEFINE_SPINLOCK(freezer_delta_lock);
44 54
45 55
46/************************************************************************** 56/**
47 * alarmtimer management code
48 */
49
50/*
51 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue 57 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
52 * @base: pointer to the base where the timer is being run 58 * @base: pointer to the base where the timer is being run
53 * @alarm: pointer to alarm being enqueued. 59 * @alarm: pointer to alarm being enqueued.
@@ -67,7 +73,7 @@ static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
67 } 73 }
68} 74}
69 75
70/* 76/**
71 * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue 77 * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
72 * @base: pointer to the base where the timer is running 78 * @base: pointer to the base where the timer is running
73 * @alarm: pointer to alarm being removed 79 * @alarm: pointer to alarm being removed
@@ -91,16 +97,16 @@ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
91 } 97 }
92} 98}
93 99
94/* 100/**
95 * alarmtimer_do_work - Handles alarm being fired. 101 * alarmtimer_do_work - Handles alarm being fired.
96 * @work: pointer to workqueue being run 102 * @work: pointer to workqueue being run
97 * 103 *
98 * When a timer fires, this runs through the timerqueue to see 104 * When a alarm timer fires, this runs through the timerqueue to
99 * which alarm timers, and run those that expired. If there are 105 * see which alarms expired, and runs those. If there are more alarm
100 * more alarm timers queued, we set the hrtimer to fire in the 106 * timers queued for the future, we set the hrtimer to fire when
101 * future. 107 * when the next future alarm timer expires.
102 */ 108 */
103void alarmtimer_do_work(struct work_struct *work) 109static void alarmtimer_do_work(struct work_struct *work)
104{ 110{
105 struct alarm_base *base = container_of(work, struct alarm_base, 111 struct alarm_base *base = container_of(work, struct alarm_base,
106 irqwork); 112 irqwork);
@@ -141,7 +147,7 @@ void alarmtimer_do_work(struct work_struct *work)
141} 147}
142 148
143 149
144/* 150/**
145 * alarmtimer_fired - Handles alarm hrtimer being fired. 151 * alarmtimer_fired - Handles alarm hrtimer being fired.
146 * @timer: pointer to hrtimer being run 152 * @timer: pointer to hrtimer being run
147 * 153 *
@@ -156,7 +162,7 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
156} 162}
157 163
158 164
159/* 165/**
160 * alarmtimer_suspend - Suspend time callback 166 * alarmtimer_suspend - Suspend time callback
161 * @dev: unused 167 * @dev: unused
162 * @state: unused 168 * @state: unused
@@ -230,17 +236,11 @@ static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
230} 236}
231 237
232 238
233/************************************************************************** 239/**
234 * alarm kernel interface code
235 */
236
237/*
238 * alarm_init - Initialize an alarm structure 240 * alarm_init - Initialize an alarm structure
239 * @alarm: ptr to alarm to be initialized 241 * @alarm: ptr to alarm to be initialized
240 * @type: the type of the alarm 242 * @type: the type of the alarm
241 * @function: callback that is run when the alarm fires 243 * @function: callback that is run when the alarm fires
242 *
243 * In-kernel interface to initializes the alarm structure.
244 */ 244 */
245void alarm_init(struct alarm *alarm, enum alarmtimer_type type, 245void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
246 void (*function)(struct alarm *)) 246 void (*function)(struct alarm *))
@@ -252,13 +252,11 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
252 alarm->enabled = 0; 252 alarm->enabled = 0;
253} 253}
254 254
255/* 255/**
256 * alarm_start - Sets an alarm to fire 256 * alarm_start - Sets an alarm to fire
257 * @alarm: ptr to alarm to set 257 * @alarm: ptr to alarm to set
258 * @start: time to run the alarm 258 * @start: time to run the alarm
259 * @period: period at which the alarm will recur 259 * @period: period at which the alarm will recur
260 *
261 * In-kernel interface set an alarm timer.
262 */ 260 */
263void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period) 261void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period)
264{ 262{
@@ -275,11 +273,9 @@ void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period)
275 spin_unlock_irqrestore(&base->lock, flags); 273 spin_unlock_irqrestore(&base->lock, flags);
276} 274}
277 275
278/* 276/**
279 * alarm_cancel - Tries to cancel an alarm timer 277 * alarm_cancel - Tries to cancel an alarm timer
280 * @alarm: ptr to alarm to be canceled 278 * @alarm: ptr to alarm to be canceled
281 *
282 * In-kernel interface to cancel an alarm timer.
283 */ 279 */
284void alarm_cancel(struct alarm *alarm) 280void alarm_cancel(struct alarm *alarm)
285{ 281{
@@ -294,15 +290,9 @@ void alarm_cancel(struct alarm *alarm)
294} 290}
295 291
296 292
297/************************************************************************** 293/**
298 * alarm posix interface code
299 */
300
301/*
302 * clock2alarm - helper that converts from clockid to alarmtypes 294 * clock2alarm - helper that converts from clockid to alarmtypes
303 * @clockid: clockid. 295 * @clockid: clockid.
304 *
305 * Helper function that converts from clockids to alarmtypes
306 */ 296 */
307static enum alarmtimer_type clock2alarm(clockid_t clockid) 297static enum alarmtimer_type clock2alarm(clockid_t clockid)
308{ 298{
@@ -313,7 +303,7 @@ static enum alarmtimer_type clock2alarm(clockid_t clockid)
313 return -1; 303 return -1;
314} 304}
315 305
316/* 306/**
317 * alarm_handle_timer - Callback for posix timers 307 * alarm_handle_timer - Callback for posix timers
318 * @alarm: alarm that fired 308 * @alarm: alarm that fired
319 * 309 *
@@ -327,7 +317,7 @@ static void alarm_handle_timer(struct alarm *alarm)
327 ptr->it_overrun++; 317 ptr->it_overrun++;
328} 318}
329 319
330/* 320/**
331 * alarm_clock_getres - posix getres interface 321 * alarm_clock_getres - posix getres interface
332 * @which_clock: clockid 322 * @which_clock: clockid
333 * @tp: timespec to fill 323 * @tp: timespec to fill
@@ -598,9 +588,6 @@ out:
598 return ret; 588 return ret;
599} 589}
600 590
601/**************************************************************************
602 * alarmtimer initialization code
603 */
604 591
605/* Suspend hook structures */ 592/* Suspend hook structures */
606static const struct dev_pm_ops alarmtimer_pm_ops = { 593static const struct dev_pm_ops alarmtimer_pm_ops = {