WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/synch/waitq.c



        goto out;
 
grab_locks:
    spinlock_lock(&t->lock);
    if ((wq = t->sleep_queue)) {        /* assignment */
        if (!(t->sleep_interruptible)) {
            /*
             * The sleep cannot be interrupted.
             */
            spinlock_unlock(&t->lock);
            goto out;
        }
           
        if (!spinlock_trylock(&wq->lock)) {
            spinlock_unlock(&t->lock);
            goto grab_locks;    /* avoid deadlock */
        }
 

    interrupts_restore(ipl);
}
 
/** Sleep until either wakeup, timeout or interruption occurs
 *
 * This is a sleep implementation which allows itself to time out or to be
 * interrupted from the sleep, restoring a failover context.
 *
 * Sleepers are organised in a FIFO fashion in a structure called wait queue.
 *
 * This function is really basic in that other functions as waitq_sleep()
 * and all the *_timeout() functions use it.
 *
 * @param wq Pointer to wait queue.
 * @param usec Timeout in microseconds.
 * @param flags Specify mode of the sleep.
 *
 * The sleep can be interrupted only if the
 * SYNCH_FLAGS_INTERRUPTIBLE bit is specified in flags.
 
 * If usec is greater than zero, regardless of the value of the
 * SYNCH_FLAGS_NON_BLOCKING bit in flags, the call will not return until either timeout,
 * interruption or wakeup comes.
 *
 * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is not set in flags, the call
 * will not return until wakeup or interruption comes.
 *
 * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is set in flags, the call will
 * immediately return, reporting either success or failure.
 *
 * @return  Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT, ESYNCH_INTERRUPTED,
 *          ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.
 *
 * @li ESYNCH_WOULD_BLOCK means that the sleep failed because at the time
 * of the call there was no pending wakeup.
 *

 * asleep at all.
 *
 * @li ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was
 * attempted.
 */
int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int flags)
{
    ipl_t ipl;
    int rc;
   
    ipl = waitq_sleep_prepare(wq);
    rc = waitq_sleep_timeout_unsafe(wq, usec, flags);
    waitq_sleep_finish(wq, rc, ipl);
    return rc;
}
 
/** Prepare to sleep in a waitq.

 * This call must be preceeded by a call to waitq_sleep_prepare()
 * and followed by a call to waitq_slee_finish().
 *
 * @param wq See waitq_sleep_timeout().
 * @param usec See waitq_sleep_timeout().
 * @param flags See waitq_sleep_timeout().
 *
 * @return See waitq_sleep_timeout().
 */
int waitq_sleep_timeout_unsafe(waitq_t *wq, __u32 usec, int flags)
{
    /* checks whether to go to sleep at all */
    if (wq->missed_wakeups) {
        wq->missed_wakeups--;
        return ESYNCH_OK_ATOMIC;
    }
    else {
        if ((flags & SYNCH_FLAGS_NON_BLOCKING) && (usec == 0)) {
            /* return immediatelly instead of going to sleep */
            return ESYNCH_WOULD_BLOCK;
        }
    }
   
    /*
     * Now we are firmly decided to go to sleep.
     */
    spinlock_lock(&THREAD->lock);
 
    if (flags & SYNCH_FLAGS_INTERRUPTIBLE) {
        /*
         * Set context that will be restored if the sleep
         * of this thread is ever interrupted.
         */
        THREAD->sleep_interruptible = true;
        if (!context_save(&THREAD->sleep_interruption_context)) {
            /* Short emulation of scheduler() return code. */
            spinlock_unlock(&THREAD->lock);
            return ESYNCH_INTERRUPTED;
        }
    } else {
        THREAD->sleep_interruptible = false;
    }
 
    if (usec) {
        /* We use the timeout variant. */
        if (!context_save(&THREAD->sleep_timeout_context)) {

Rev 1467	Rev 1502
Line 133...	Line 133...
133	goto out;	133	goto out;
134		134
135	grab_locks:	135	grab_locks:
136	spinlock_lock(&t->lock);	136	spinlock_lock(&t->lock);
137	if ((wq = t->sleep_queue)) { /* assignment */	137	if ((wq = t->sleep_queue)) { /* assignment */
-		138	if (!(t->sleep_interruptible)) {
-		139	/*
-		140	* The sleep cannot be interrupted.
-		141	*/
-		142	spinlock_unlock(&t->lock);
-		143	goto out;
-		144	}
-		145
138	if (!spinlock_trylock(&wq->lock)) {	146	if (!spinlock_trylock(&wq->lock)) {
139	spinlock_unlock(&t->lock);	147	spinlock_unlock(&t->lock);
140	goto grab_locks; /* avoid deadlock */	148	goto grab_locks; /* avoid deadlock */
141	}	149	}
142		150
Line 157...	Line 165...
157	interrupts_restore(ipl);	165	interrupts_restore(ipl);
158	}	166	}
159		167
160	/** Sleep until either wakeup, timeout or interruption occurs	168	/** Sleep until either wakeup, timeout or interruption occurs
161	*	169	*
162	* This is a sleep implementation which allows itself to be	170	* This is a sleep implementation which allows itself to time out or to be
163	* interrupted from the sleep, restoring a failover context.	171	* interrupted from the sleep, restoring a failover context.
164	*	172	*
165	* Sleepers are organised in a FIFO fashion in a structure called wait queue.	173	* Sleepers are organised in a FIFO fashion in a structure called wait queue.
166	*	174	*
167	* This function is really basic in that other functions as waitq_sleep()	175	* This function is really basic in that other functions as waitq_sleep()
168	* and all the *_timeout() functions use it.	176	* and all the *_timeout() functions use it.
169	*	177	*
170	* @param wq Pointer to wait queue.	178	* @param wq Pointer to wait queue.
171	* @param usec Timeout in microseconds.	179	* @param usec Timeout in microseconds.
172	* @param nonblocking Blocking vs. non-blocking operation mode switch.	180	* @param flags Specify mode of the sleep.
173	*	181	*
-		182	* The sleep can be interrupted only if the
-		183	* SYNCH_FLAGS_INTERRUPTIBLE bit is specified in flags.
-		184
174	* If usec is greater than zero, regardless of the value of nonblocking,	185	* If usec is greater than zero, regardless of the value of the
175	* the call will not return until either timeout or wakeup comes.	186	* SYNCH_FLAGS_NON_BLOCKING bit in flags, the call will not return until either timeout,
-		187	* interruption or wakeup comes.
176	*	188	*
177	* If usec is zero and @nonblocking is zero (false), the call	189	* If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is not set in flags, the call
178	* will not return until wakeup comes.	190	* will not return until wakeup or interruption comes.
179	*	191	*
180	* If usec is zero and nonblocking is non-zero (true), the call will	192	* If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is set in flags, the call will
181	* immediately return, reporting either success or failure.	193	* immediately return, reporting either success or failure.
182	*	194	*
183	* @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,	195	* @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT, ESYNCH_INTERRUPTED,
184	* ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.	196	* ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.
185	*	197	*
186	* @li ESYNCH_WOULD_BLOCK means that the sleep failed because at the time	198	* @li ESYNCH_WOULD_BLOCK means that the sleep failed because at the time
187	* of the call there was no pending wakeup.	199	* of the call there was no pending wakeup.
188	*	200	*
Line 195...	Line 207...
195	* asleep at all.	207	* asleep at all.
196	*	208	*
197	* @li ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was	209	* @li ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was
198	* attempted.	210	* attempted.
199	*/	211	*/
200	int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int nonblocking)	212	int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int flags)
201	{	213	{
202	ipl_t ipl;	214	ipl_t ipl;
203	int rc;	215	int rc;
204		216
205	ipl = waitq_sleep_prepare(wq);	217	ipl = waitq_sleep_prepare(wq);
206	rc = waitq_sleep_timeout_unsafe(wq, usec, nonblocking);	218	rc = waitq_sleep_timeout_unsafe(wq, usec, flags);
207	waitq_sleep_finish(wq, rc, ipl);	219	waitq_sleep_finish(wq, rc, ipl);
208	return rc;	220	return rc;
209	}	221	}
210		222
211	/** Prepare to sleep in a waitq.	223	/** Prepare to sleep in a waitq.
Line 274...	Line 286...
274	* This call must be preceeded by a call to waitq_sleep_prepare()	286	* This call must be preceeded by a call to waitq_sleep_prepare()
275	* and followed by a call to waitq_slee_finish().	287	* and followed by a call to waitq_slee_finish().
276	*	288	*
277	* @param wq See waitq_sleep_timeout().	289	* @param wq See waitq_sleep_timeout().
278	* @param usec See waitq_sleep_timeout().	290	* @param usec See waitq_sleep_timeout().
279	* @param nonblocking See waitq_sleep_timeout().	291	* @param flags See waitq_sleep_timeout().
280	*	292	*
281	* @return See waitq_sleep_timeout().	293	* @return See waitq_sleep_timeout().
282	*/	294	*/
283	int waitq_sleep_timeout_unsafe(waitq_t *wq, __u32 usec, int nonblocking)	295	int waitq_sleep_timeout_unsafe(waitq_t *wq, __u32 usec, int flags)
284	{	296	{
285	/* checks whether to go to sleep at all */	297	/* checks whether to go to sleep at all */
286	if (wq->missed_wakeups) {	298	if (wq->missed_wakeups) {
287	wq->missed_wakeups--;	299	wq->missed_wakeups--;
288	return ESYNCH_OK_ATOMIC;	300	return ESYNCH_OK_ATOMIC;
289	}	301	}
290	else {	302	else {
291	if (nonblocking && (usec == 0)) {	303	if ((flags & SYNCH_FLAGS_NON_BLOCKING) && (usec == 0)) {
292	/* return immediatelly instead of going to sleep */	304	/* return immediatelly instead of going to sleep */
293	return ESYNCH_WOULD_BLOCK;	305	return ESYNCH_WOULD_BLOCK;
294	}	306	}
295	}	307	}
296		308
297	/*	309	/*
298	* Now we are firmly decided to go to sleep.	310	* Now we are firmly decided to go to sleep.
299	*/	311	*/
300	spinlock_lock(&THREAD->lock);	312	spinlock_lock(&THREAD->lock);
301		313
-		314	if (flags & SYNCH_FLAGS_INTERRUPTIBLE) {
302	/*	315	/*
303	* Set context that will be restored if the sleep	316	* Set context that will be restored if the sleep
304	* of this thread is ever interrupted.	317	* of this thread is ever interrupted.
305	*/	318	*/
-		319	THREAD->sleep_interruptible = true;
306	if (!context_save(&THREAD->sleep_interruption_context)) {	320	if (!context_save(&THREAD->sleep_interruption_context)) {
307	/* Short emulation of scheduler() return code. */	321	/* Short emulation of scheduler() return code. */
308	spinlock_unlock(&THREAD->lock);	322	spinlock_unlock(&THREAD->lock);
309	return ESYNCH_INTERRUPTED;	323	return ESYNCH_INTERRUPTED;
-		324	}
-		325	} else {
-		326	THREAD->sleep_interruptible = false;
310	}	327	}
311		328
312	if (usec) {	329	if (usec) {
313	/* We use the timeout variant. */	330	/* We use the timeout variant. */
314	if (!context_save(&THREAD->sleep_timeout_context)) {	331	if (!context_save(&THREAD->sleep_timeout_context)) {

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/synch/waitq.c – Rev 1467 → 1502