linux-master/fs/select.c

10  *     flag set in its personality we do *not* modify the given timeout
40  * Estimate expected accuracy in ns from a timeval.
115  * work.  poll_wait() is an inline-function defined in <linux/poll.h>,
194 	 * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
195 	 * and is paired with smp_store_mb() in poll_schedule_timeout.
205 	 * pass in @sync.  @sync is scheduled to be removed and once
251 	 * the counterpart rmb of the wmb in pollwake() such that data
357 	 * If an application puts its timeval in read-only memory, we
375 	unsigned long *in, *out, *ex;
414 #define FDS_IN(fds, n)		(fds->in + n)
427 	/* handle last in-complete long-word first */
468 static inline void wait_key_set(poll_table *wait, unsigned long in,
473 	if (in & bit)
512 		inp = fds->in; outp = fds->out; exp = fds->ex;
516 			unsigned long in, out, ex, all_bits, bit = 1, j;
520 			in = *inp++; out = *outp++; ex = *exp++;
521 			all_bits = in | out | ex;
536 					wait_key_set(wait, in, out, bit,
542 				if ((mask & POLLIN_SET) && (in & bit)) {
649 	 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
650 	 * since we used fdset we need to allocate memory in units of
656 		/* Not enough space in on-stack array; must use kmalloc */
666 	fds.in      = bits;
673 	if ((ret = get_fd_set(n, inp, fds.in)) ||
850  * interested in events matching the pollfd->events mask, and the result
851  * matching that mask is both recorded in pollfd->revents and returned. The
1217 	 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
1218 	 * since we used fdset we need to allocate memory in units of
1229 	fds.in      = (unsigned long *)  bits;
1236 	if ((ret = compat_get_fd_set(n, inp, fds.in)) ||