linux-4.4.1/do_poll()(gen) の変更点

• 追加された行はこの色です。
• 削除された行はこの色です。
• linux-4.4.1/do_poll()(gen) へ行く。
• linux-4.4.1/do_poll()(gen) の差分を削除

*参照元 [#z3e08e80]
#backlinks

*説明 [#sed76b7e]
-パス: [[linux-4.4.1/fs/select.c]]

-FIXME: これは何？
--説明


**引数 [#p0970b1d]
-unsigned int nfds
--
-struct poll_list *list
--
--[[linux-4.4.1/poll_list]]
-struct poll_wqueues *wait
--
--[[linux-4.4.1/poll_wqueues]]
-struct timespec *end_time
--
--[[linux-4.4.1/timespec]]


**返り値 [#r0630027]
-int
--


**参考 [#e0986963]


*実装 [#qe78df94]
 static int do_poll(unsigned int nfds,  struct poll_list *list,
 		   struct poll_wqueues *wait, struct timespec *end_time)
 {
 	poll_table* pt = &wait->pt;
 	ktime_t expire, *to = NULL;
 	int timed_out = 0, count = 0;
 	unsigned long slack = 0;
 	unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
 	unsigned long busy_end = 0;
 
-
--[[linux-4.4.1/poll_table]]
--[[linux-4.4.1/ktime_t]]
--[[linux-4.4.1/net_busy_loop_on()]]

 	/* Optimise the no-wait case */
 	if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
 		pt->_qproc = NULL;
 		timed_out = 1;
 	}
 
 	if (end_time && !timed_out)
 		slack = select_estimate_accuracy(end_time);
 
-
--[[linux-4.4.1/select_estimate_accuracy()]]

 	for (;;) {
 		struct poll_list *walk;
 		bool can_busy_loop = false;
 
 		for (walk = list; walk != NULL; walk = walk->next) {
 			struct pollfd * pfd, * pfd_end;
 
-
--[[linux-4.4.1/pollfd]]

 			pfd = walk->entries;
 			pfd_end = pfd + walk->len;
 			for (; pfd != pfd_end; pfd++) {
 				/*
 				 * Fish for events. If we found one, record it
 				 * and kill poll_table->_qproc, so we don't
 				 * needlessly register any other waiters after
 				 * this. They'll get immediately deregistered
 				 * when we break out and return.
 				 */
 				if (do_pollfd(pfd, pt, &can_busy_loop,
 					      busy_flag)) {
 					count++;
 					pt->_qproc = NULL;
 					/* found something, stop busy polling */
 					busy_flag = 0;
 					can_busy_loop = false;
 				}
-
--[[linux-4.4.1/do_pollfd()]]

 			}
 		}
 		/*
 		 * All waiters have already been registered, so don't provide
 		 * a poll_table->_qproc to them on the next loop iteration.
 		 */
 		pt->_qproc = NULL;
 		if (!count) {
 			count = wait->error;
 			if (signal_pending(current))
 				count = -EINTR;
 		}
 		if (count || timed_out)
 			break;
 
-
--[[linux-4.4.1/signal_pending()]]

 		/* only if found POLL_BUSY_LOOP sockets && not out of time */
 		if (can_busy_loop && !need_resched()) {
 			if (!busy_end) {
 				busy_end = busy_loop_end_time();
 				continue;
 			}
 			if (!busy_loop_timeout(busy_end))
 				continue;
 		}
 		busy_flag = 0;
 
-
--[[linux-4.4.1/need_resched()]]
--[[linux-4.4.1/busy_loop_end_time()]]
--[[linux-4.4.1/busy_loop_timeout()]]

 		/*
 		 * If this is the first loop and we have a timeout
 		 * given, then we convert to ktime_t and set the to
 		 * pointer to the expiry value.
 		 */
 		if (end_time && !to) {
 			expire = timespec_to_ktime(*end_time);
 			to = &expire;
 		}
 
-
--[[linux-4.4.1/timespec_to_ktime()]]

 		if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
 			timed_out = 1;
-
--[[linux-4.4.1/poll_schedule_timeout()]]

 	}
 	return count;
 }


*コメント [#i397c65b]