DaVinci: DM365: Add Support for new Revision of silicon
[linux-ginger.git] / fs / select.c
blob8084834e123efed4e100fe030e2e26ced3ede1c9
1 /*
2 * This file contains the procedures for the handling of select and poll
4 * Created for Linux based loosely upon Mathius Lattner's minix
5 * patches by Peter MacDonald. Heavily edited by Linus.
7 * 4 February 1994
8 * COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
9 * flag set in its personality we do *not* modify the given timeout
10 * parameter to reflect time remaining.
12 * 24 January 2000
13 * Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation
14 * of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
17 #include <linux/kernel.h>
18 #include <linux/syscalls.h>
19 #include <linux/module.h>
20 #include <linux/slab.h>
21 #include <linux/poll.h>
22 #include <linux/personality.h> /* for STICKY_TIMEOUTS */
23 #include <linux/file.h>
24 #include <linux/fdtable.h>
25 #include <linux/fs.h>
26 #include <linux/rcupdate.h>
27 #include <linux/hrtimer.h>
29 #include <asm/uaccess.h>
33 * Estimate expected accuracy in ns from a timeval.
35 * After quite a bit of churning around, we've settled on
36 * a simple thing of taking 0.1% of the timeout as the
37 * slack, with a cap of 100 msec.
38 * "nice" tasks get a 0.5% slack instead.
40 * Consider this comment an open invitation to come up with even
41 * better solutions..
44 static long __estimate_accuracy(struct timespec *tv)
46 long slack;
47 int divfactor = 1000;
49 if (task_nice(current) > 0)
50 divfactor = divfactor / 5;
52 slack = tv->tv_nsec / divfactor;
53 slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
55 if (slack > 100 * NSEC_PER_MSEC)
56 slack = 100 * NSEC_PER_MSEC;
58 if (slack < 0)
59 slack = 0;
60 return slack;
63 static long estimate_accuracy(struct timespec *tv)
65 unsigned long ret;
66 struct timespec now;
69 * Realtime tasks get a slack of 0 for obvious reasons.
72 if (rt_task(current))
73 return 0;
75 ktime_get_ts(&now);
76 now = timespec_sub(*tv, now);
77 ret = __estimate_accuracy(&now);
78 if (ret < current->timer_slack_ns)
79 return current->timer_slack_ns;
80 return ret;
85 struct poll_table_page {
86 struct poll_table_page * next;
87 struct poll_table_entry * entry;
88 struct poll_table_entry entries[0];
91 #define POLL_TABLE_FULL(table) \
92 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
95 * Ok, Peter made a complicated, but straightforward multiple_wait() function.
96 * I have rewritten this, taking some shortcuts: This code may not be easy to
97 * follow, but it should be free of race-conditions, and it's practical. If you
98 * understand what I'm doing here, then you understand how the linux
99 * sleep/wakeup mechanism works.
101 * Two very simple procedures, poll_wait() and poll_freewait() make all the
102 * work. poll_wait() is an inline-function defined in <linux/poll.h>,
103 * as all select/poll functions have to call it to add an entry to the
104 * poll table.
106 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
107 poll_table *p);
109 void poll_initwait(struct poll_wqueues *pwq)
111 init_poll_funcptr(&pwq->pt, __pollwait);
112 pwq->polling_task = current;
113 pwq->triggered = 0;
114 pwq->error = 0;
115 pwq->table = NULL;
116 pwq->inline_index = 0;
118 EXPORT_SYMBOL(poll_initwait);
120 static void free_poll_entry(struct poll_table_entry *entry)
122 remove_wait_queue(entry->wait_address, &entry->wait);
123 fput(entry->filp);
126 void poll_freewait(struct poll_wqueues *pwq)
128 struct poll_table_page * p = pwq->table;
129 int i;
130 for (i = 0; i < pwq->inline_index; i++)
131 free_poll_entry(pwq->inline_entries + i);
132 while (p) {
133 struct poll_table_entry * entry;
134 struct poll_table_page *old;
136 entry = p->entry;
137 do {
138 entry--;
139 free_poll_entry(entry);
140 } while (entry > p->entries);
141 old = p;
142 p = p->next;
143 free_page((unsigned long) old);
146 EXPORT_SYMBOL(poll_freewait);
148 static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
150 struct poll_table_page *table = p->table;
152 if (p->inline_index < N_INLINE_POLL_ENTRIES)
153 return p->inline_entries + p->inline_index++;
155 if (!table || POLL_TABLE_FULL(table)) {
156 struct poll_table_page *new_table;
158 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
159 if (!new_table) {
160 p->error = -ENOMEM;
161 return NULL;
163 new_table->entry = new_table->entries;
164 new_table->next = table;
165 p->table = new_table;
166 table = new_table;
169 return table->entry++;
172 static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
174 struct poll_wqueues *pwq = wait->private;
175 DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
178 * Although this function is called under waitqueue lock, LOCK
179 * doesn't imply write barrier and the users expect write
180 * barrier semantics on wakeup functions. The following
181 * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
182 * and is paired with set_mb() in poll_schedule_timeout.
184 smp_wmb();
185 pwq->triggered = 1;
188 * Perform the default wake up operation using a dummy
189 * waitqueue.
191 * TODO: This is hacky but there currently is no interface to
192 * pass in @sync. @sync is scheduled to be removed and once
193 * that happens, wake_up_process() can be used directly.
195 return default_wake_function(&dummy_wait, mode, sync, key);
198 static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
200 struct poll_table_entry *entry;
202 entry = container_of(wait, struct poll_table_entry, wait);
203 if (key && !((unsigned long)key & entry->key))
204 return 0;
205 return __pollwake(wait, mode, sync, key);
208 /* Add a new entry */
209 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
210 poll_table *p)
212 struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
213 struct poll_table_entry *entry = poll_get_entry(pwq);
214 if (!entry)
215 return;
216 get_file(filp);
217 entry->filp = filp;
218 entry->wait_address = wait_address;
219 entry->key = p->key;
220 init_waitqueue_func_entry(&entry->wait, pollwake);
221 entry->wait.private = pwq;
222 add_wait_queue(wait_address, &entry->wait);
225 int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
226 ktime_t *expires, unsigned long slack)
228 int rc = -EINTR;
230 set_current_state(state);
231 if (!pwq->triggered)
232 rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
233 __set_current_state(TASK_RUNNING);
236 * Prepare for the next iteration.
238 * The following set_mb() serves two purposes. First, it's
239 * the counterpart rmb of the wmb in pollwake() such that data
240 * written before wake up is always visible after wake up.
241 * Second, the full barrier guarantees that triggered clearing
242 * doesn't pass event check of the next iteration. Note that
243 * this problem doesn't exist for the first iteration as
244 * add_wait_queue() has full barrier semantics.
246 set_mb(pwq->triggered, 0);
248 return rc;
250 EXPORT_SYMBOL(poll_schedule_timeout);
253 * poll_select_set_timeout - helper function to setup the timeout value
254 * @to: pointer to timespec variable for the final timeout
255 * @sec: seconds (from user space)
256 * @nsec: nanoseconds (from user space)
258 * Note, we do not use a timespec for the user space value here, That
259 * way we can use the function for timeval and compat interfaces as well.
261 * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0.
263 int poll_select_set_timeout(struct timespec *to, long sec, long nsec)
265 struct timespec ts = {.tv_sec = sec, .tv_nsec = nsec};
267 if (!timespec_valid(&ts))
268 return -EINVAL;
270 /* Optimize for the zero timeout value here */
271 if (!sec && !nsec) {
272 to->tv_sec = to->tv_nsec = 0;
273 } else {
274 ktime_get_ts(to);
275 *to = timespec_add_safe(*to, ts);
277 return 0;
280 static int poll_select_copy_remaining(struct timespec *end_time, void __user *p,
281 int timeval, int ret)
283 struct timespec rts;
284 struct timeval rtv;
286 if (!p)
287 return ret;
289 if (current->personality & STICKY_TIMEOUTS)
290 goto sticky;
292 /* No update for zero timeout */
293 if (!end_time->tv_sec && !end_time->tv_nsec)
294 return ret;
296 ktime_get_ts(&rts);
297 rts = timespec_sub(*end_time, rts);
298 if (rts.tv_sec < 0)
299 rts.tv_sec = rts.tv_nsec = 0;
301 if (timeval) {
302 rtv.tv_sec = rts.tv_sec;
303 rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
305 if (!copy_to_user(p, &rtv, sizeof(rtv)))
306 return ret;
308 } else if (!copy_to_user(p, &rts, sizeof(rts)))
309 return ret;
312 * If an application puts its timeval in read-only memory, we
313 * don't want the Linux-specific update to the timeval to
314 * cause a fault after the select has completed
315 * successfully. However, because we're not updating the
316 * timeval, we can't restart the system call.
319 sticky:
320 if (ret == -ERESTARTNOHAND)
321 ret = -EINTR;
322 return ret;
325 #define FDS_IN(fds, n) (fds->in + n)
326 #define FDS_OUT(fds, n) (fds->out + n)
327 #define FDS_EX(fds, n) (fds->ex + n)
329 #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
331 static int max_select_fd(unsigned long n, fd_set_bits *fds)
333 unsigned long *open_fds;
334 unsigned long set;
335 int max;
336 struct fdtable *fdt;
338 /* handle last in-complete long-word first */
339 set = ~(~0UL << (n & (__NFDBITS-1)));
340 n /= __NFDBITS;
341 fdt = files_fdtable(current->files);
342 open_fds = fdt->open_fds->fds_bits+n;
343 max = 0;
344 if (set) {
345 set &= BITS(fds, n);
346 if (set) {
347 if (!(set & ~*open_fds))
348 goto get_max;
349 return -EBADF;
352 while (n) {
353 open_fds--;
354 n--;
355 set = BITS(fds, n);
356 if (!set)
357 continue;
358 if (set & ~*open_fds)
359 return -EBADF;
360 if (max)
361 continue;
362 get_max:
363 do {
364 max++;
365 set >>= 1;
366 } while (set);
367 max += n * __NFDBITS;
370 return max;
373 #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
374 #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
375 #define POLLEX_SET (POLLPRI)
377 static inline void wait_key_set(poll_table *wait, unsigned long in,
378 unsigned long out, unsigned long bit)
380 if (wait) {
381 wait->key = POLLEX_SET;
382 if (in & bit)
383 wait->key |= POLLIN_SET;
384 if (out & bit)
385 wait->key |= POLLOUT_SET;
389 int do_select(int n, fd_set_bits *fds, struct timespec *end_time)
391 ktime_t expire, *to = NULL;
392 struct poll_wqueues table;
393 poll_table *wait;
394 int retval, i, timed_out = 0;
395 unsigned long slack = 0;
397 rcu_read_lock();
398 retval = max_select_fd(n, fds);
399 rcu_read_unlock();
401 if (retval < 0)
402 return retval;
403 n = retval;
405 poll_initwait(&table);
406 wait = &table.pt;
407 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
408 wait = NULL;
409 timed_out = 1;
412 if (end_time && !timed_out)
413 slack = estimate_accuracy(end_time);
415 retval = 0;
416 for (;;) {
417 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
419 inp = fds->in; outp = fds->out; exp = fds->ex;
420 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
422 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
423 unsigned long in, out, ex, all_bits, bit = 1, mask, j;
424 unsigned long res_in = 0, res_out = 0, res_ex = 0;
425 const struct file_operations *f_op = NULL;
426 struct file *file = NULL;
428 in = *inp++; out = *outp++; ex = *exp++;
429 all_bits = in | out | ex;
430 if (all_bits == 0) {
431 i += __NFDBITS;
432 continue;
435 for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
436 int fput_needed;
437 if (i >= n)
438 break;
439 if (!(bit & all_bits))
440 continue;
441 file = fget_light(i, &fput_needed);
442 if (file) {
443 f_op = file->f_op;
444 mask = DEFAULT_POLLMASK;
445 if (f_op && f_op->poll) {
446 wait_key_set(wait, in, out, bit);
447 mask = (*f_op->poll)(file, wait);
449 fput_light(file, fput_needed);
450 if ((mask & POLLIN_SET) && (in & bit)) {
451 res_in |= bit;
452 retval++;
453 wait = NULL;
455 if ((mask & POLLOUT_SET) && (out & bit)) {
456 res_out |= bit;
457 retval++;
458 wait = NULL;
460 if ((mask & POLLEX_SET) && (ex & bit)) {
461 res_ex |= bit;
462 retval++;
463 wait = NULL;
467 if (res_in)
468 *rinp = res_in;
469 if (res_out)
470 *routp = res_out;
471 if (res_ex)
472 *rexp = res_ex;
473 cond_resched();
475 wait = NULL;
476 if (retval || timed_out || signal_pending(current))
477 break;
478 if (table.error) {
479 retval = table.error;
480 break;
484 * If this is the first loop and we have a timeout
485 * given, then we convert to ktime_t and set the to
486 * pointer to the expiry value.
488 if (end_time && !to) {
489 expire = timespec_to_ktime(*end_time);
490 to = &expire;
493 if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
494 to, slack))
495 timed_out = 1;
498 poll_freewait(&table);
500 return retval;
504 * We can actually return ERESTARTSYS instead of EINTR, but I'd
505 * like to be certain this leads to no problems. So I return
506 * EINTR just for safety.
508 * Update: ERESTARTSYS breaks at least the xview clock binary, so
509 * I'm trying ERESTARTNOHAND which restart only when you want to.
511 #define MAX_SELECT_SECONDS \
512 ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)
514 int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
515 fd_set __user *exp, struct timespec *end_time)
517 fd_set_bits fds;
518 void *bits;
519 int ret, max_fds;
520 unsigned int size;
521 struct fdtable *fdt;
522 /* Allocate small arguments on the stack to save memory and be faster */
523 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
525 ret = -EINVAL;
526 if (n < 0)
527 goto out_nofds;
529 /* max_fds can increase, so grab it once to avoid race */
530 rcu_read_lock();
531 fdt = files_fdtable(current->files);
532 max_fds = fdt->max_fds;
533 rcu_read_unlock();
534 if (n > max_fds)
535 n = max_fds;
538 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
539 * since we used fdset we need to allocate memory in units of
540 * long-words.
542 size = FDS_BYTES(n);
543 bits = stack_fds;
544 if (size > sizeof(stack_fds) / 6) {
545 /* Not enough space in on-stack array; must use kmalloc */
546 ret = -ENOMEM;
547 bits = kmalloc(6 * size, GFP_KERNEL);
548 if (!bits)
549 goto out_nofds;
551 fds.in = bits;
552 fds.out = bits + size;
553 fds.ex = bits + 2*size;
554 fds.res_in = bits + 3*size;
555 fds.res_out = bits + 4*size;
556 fds.res_ex = bits + 5*size;
558 if ((ret = get_fd_set(n, inp, fds.in)) ||
559 (ret = get_fd_set(n, outp, fds.out)) ||
560 (ret = get_fd_set(n, exp, fds.ex)))
561 goto out;
562 zero_fd_set(n, fds.res_in);
563 zero_fd_set(n, fds.res_out);
564 zero_fd_set(n, fds.res_ex);
566 ret = do_select(n, &fds, end_time);
568 if (ret < 0)
569 goto out;
570 if (!ret) {
571 ret = -ERESTARTNOHAND;
572 if (signal_pending(current))
573 goto out;
574 ret = 0;
577 if (set_fd_set(n, inp, fds.res_in) ||
578 set_fd_set(n, outp, fds.res_out) ||
579 set_fd_set(n, exp, fds.res_ex))
580 ret = -EFAULT;
582 out:
583 if (bits != stack_fds)
584 kfree(bits);
585 out_nofds:
586 return ret;
589 SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
590 fd_set __user *, exp, struct timeval __user *, tvp)
592 struct timespec end_time, *to = NULL;
593 struct timeval tv;
594 int ret;
596 if (tvp) {
597 if (copy_from_user(&tv, tvp, sizeof(tv)))
598 return -EFAULT;
600 to = &end_time;
601 if (poll_select_set_timeout(to,
602 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
603 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
604 return -EINVAL;
607 ret = core_sys_select(n, inp, outp, exp, to);
608 ret = poll_select_copy_remaining(&end_time, tvp, 1, ret);
610 return ret;
613 #ifdef HAVE_SET_RESTORE_SIGMASK
614 static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
615 fd_set __user *exp, struct timespec __user *tsp,
616 const sigset_t __user *sigmask, size_t sigsetsize)
618 sigset_t ksigmask, sigsaved;
619 struct timespec ts, end_time, *to = NULL;
620 int ret;
622 if (tsp) {
623 if (copy_from_user(&ts, tsp, sizeof(ts)))
624 return -EFAULT;
626 to = &end_time;
627 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
628 return -EINVAL;
631 if (sigmask) {
632 /* XXX: Don't preclude handling different sized sigset_t's. */
633 if (sigsetsize != sizeof(sigset_t))
634 return -EINVAL;
635 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
636 return -EFAULT;
638 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
639 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
642 ret = core_sys_select(n, inp, outp, exp, to);
643 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
645 if (ret == -ERESTARTNOHAND) {
647 * Don't restore the signal mask yet. Let do_signal() deliver
648 * the signal on the way back to userspace, before the signal
649 * mask is restored.
651 if (sigmask) {
652 memcpy(&current->saved_sigmask, &sigsaved,
653 sizeof(sigsaved));
654 set_restore_sigmask();
656 } else if (sigmask)
657 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
659 return ret;
663 * Most architectures can't handle 7-argument syscalls. So we provide a
664 * 6-argument version where the sixth argument is a pointer to a structure
665 * which has a pointer to the sigset_t itself followed by a size_t containing
666 * the sigset size.
668 SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
669 fd_set __user *, exp, struct timespec __user *, tsp,
670 void __user *, sig)
672 size_t sigsetsize = 0;
673 sigset_t __user *up = NULL;
675 if (sig) {
676 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
677 || __get_user(up, (sigset_t __user * __user *)sig)
678 || __get_user(sigsetsize,
679 (size_t __user *)(sig+sizeof(void *))))
680 return -EFAULT;
683 return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize);
685 #endif /* HAVE_SET_RESTORE_SIGMASK */
687 struct poll_list {
688 struct poll_list *next;
689 int len;
690 struct pollfd entries[0];
693 #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
696 * Fish for pollable events on the pollfd->fd file descriptor. We're only
697 * interested in events matching the pollfd->events mask, and the result
698 * matching that mask is both recorded in pollfd->revents and returned. The
699 * pwait poll_table will be used by the fd-provided poll handler for waiting,
700 * if non-NULL.
702 static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
704 unsigned int mask;
705 int fd;
707 mask = 0;
708 fd = pollfd->fd;
709 if (fd >= 0) {
710 int fput_needed;
711 struct file * file;
713 file = fget_light(fd, &fput_needed);
714 mask = POLLNVAL;
715 if (file != NULL) {
716 mask = DEFAULT_POLLMASK;
717 if (file->f_op && file->f_op->poll) {
718 if (pwait)
719 pwait->key = pollfd->events |
720 POLLERR | POLLHUP;
721 mask = file->f_op->poll(file, pwait);
723 /* Mask out unneeded events. */
724 mask &= pollfd->events | POLLERR | POLLHUP;
725 fput_light(file, fput_needed);
728 pollfd->revents = mask;
730 return mask;
733 static int do_poll(unsigned int nfds, struct poll_list *list,
734 struct poll_wqueues *wait, struct timespec *end_time)
736 poll_table* pt = &wait->pt;
737 ktime_t expire, *to = NULL;
738 int timed_out = 0, count = 0;
739 unsigned long slack = 0;
741 /* Optimise the no-wait case */
742 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
743 pt = NULL;
744 timed_out = 1;
747 if (end_time && !timed_out)
748 slack = estimate_accuracy(end_time);
750 for (;;) {
751 struct poll_list *walk;
753 for (walk = list; walk != NULL; walk = walk->next) {
754 struct pollfd * pfd, * pfd_end;
756 pfd = walk->entries;
757 pfd_end = pfd + walk->len;
758 for (; pfd != pfd_end; pfd++) {
760 * Fish for events. If we found one, record it
761 * and kill the poll_table, so we don't
762 * needlessly register any other waiters after
763 * this. They'll get immediately deregistered
764 * when we break out and return.
766 if (do_pollfd(pfd, pt)) {
767 count++;
768 pt = NULL;
773 * All waiters have already been registered, so don't provide
774 * a poll_table to them on the next loop iteration.
776 pt = NULL;
777 if (!count) {
778 count = wait->error;
779 if (signal_pending(current))
780 count = -EINTR;
782 if (count || timed_out)
783 break;
786 * If this is the first loop and we have a timeout
787 * given, then we convert to ktime_t and set the to
788 * pointer to the expiry value.
790 if (end_time && !to) {
791 expire = timespec_to_ktime(*end_time);
792 to = &expire;
795 if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
796 timed_out = 1;
798 return count;
801 #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
802 sizeof(struct pollfd))
804 int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
805 struct timespec *end_time)
807 struct poll_wqueues table;
808 int err = -EFAULT, fdcount, len, size;
809 /* Allocate small arguments on the stack to save memory and be
810 faster - use long to make sure the buffer is aligned properly
811 on 64 bit archs to avoid unaligned access */
812 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
813 struct poll_list *const head = (struct poll_list *)stack_pps;
814 struct poll_list *walk = head;
815 unsigned long todo = nfds;
817 if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
818 return -EINVAL;
820 len = min_t(unsigned int, nfds, N_STACK_PPS);
821 for (;;) {
822 walk->next = NULL;
823 walk->len = len;
824 if (!len)
825 break;
827 if (copy_from_user(walk->entries, ufds + nfds-todo,
828 sizeof(struct pollfd) * walk->len))
829 goto out_fds;
831 todo -= walk->len;
832 if (!todo)
833 break;
835 len = min(todo, POLLFD_PER_PAGE);
836 size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
837 walk = walk->next = kmalloc(size, GFP_KERNEL);
838 if (!walk) {
839 err = -ENOMEM;
840 goto out_fds;
844 poll_initwait(&table);
845 fdcount = do_poll(nfds, head, &table, end_time);
846 poll_freewait(&table);
848 for (walk = head; walk; walk = walk->next) {
849 struct pollfd *fds = walk->entries;
850 int j;
852 for (j = 0; j < walk->len; j++, ufds++)
853 if (__put_user(fds[j].revents, &ufds->revents))
854 goto out_fds;
857 err = fdcount;
858 out_fds:
859 walk = head->next;
860 while (walk) {
861 struct poll_list *pos = walk;
862 walk = walk->next;
863 kfree(pos);
866 return err;
869 static long do_restart_poll(struct restart_block *restart_block)
871 struct pollfd __user *ufds = restart_block->poll.ufds;
872 int nfds = restart_block->poll.nfds;
873 struct timespec *to = NULL, end_time;
874 int ret;
876 if (restart_block->poll.has_timeout) {
877 end_time.tv_sec = restart_block->poll.tv_sec;
878 end_time.tv_nsec = restart_block->poll.tv_nsec;
879 to = &end_time;
882 ret = do_sys_poll(ufds, nfds, to);
884 if (ret == -EINTR) {
885 restart_block->fn = do_restart_poll;
886 ret = -ERESTART_RESTARTBLOCK;
888 return ret;
891 SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
892 long, timeout_msecs)
894 struct timespec end_time, *to = NULL;
895 int ret;
897 if (timeout_msecs >= 0) {
898 to = &end_time;
899 poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
900 NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
903 ret = do_sys_poll(ufds, nfds, to);
905 if (ret == -EINTR) {
906 struct restart_block *restart_block;
908 restart_block = &current_thread_info()->restart_block;
909 restart_block->fn = do_restart_poll;
910 restart_block->poll.ufds = ufds;
911 restart_block->poll.nfds = nfds;
913 if (timeout_msecs >= 0) {
914 restart_block->poll.tv_sec = end_time.tv_sec;
915 restart_block->poll.tv_nsec = end_time.tv_nsec;
916 restart_block->poll.has_timeout = 1;
917 } else
918 restart_block->poll.has_timeout = 0;
920 ret = -ERESTART_RESTARTBLOCK;
922 return ret;
925 #ifdef HAVE_SET_RESTORE_SIGMASK
926 SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
927 struct timespec __user *, tsp, const sigset_t __user *, sigmask,
928 size_t, sigsetsize)
930 sigset_t ksigmask, sigsaved;
931 struct timespec ts, end_time, *to = NULL;
932 int ret;
934 if (tsp) {
935 if (copy_from_user(&ts, tsp, sizeof(ts)))
936 return -EFAULT;
938 to = &end_time;
939 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
940 return -EINVAL;
943 if (sigmask) {
944 /* XXX: Don't preclude handling different sized sigset_t's. */
945 if (sigsetsize != sizeof(sigset_t))
946 return -EINVAL;
947 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
948 return -EFAULT;
950 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
951 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
954 ret = do_sys_poll(ufds, nfds, to);
956 /* We can restart this syscall, usually */
957 if (ret == -EINTR) {
959 * Don't restore the signal mask yet. Let do_signal() deliver
960 * the signal on the way back to userspace, before the signal
961 * mask is restored.
963 if (sigmask) {
964 memcpy(&current->saved_sigmask, &sigsaved,
965 sizeof(sigsaved));
966 set_restore_sigmask();
968 ret = -ERESTARTNOHAND;
969 } else if (sigmask)
970 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
972 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
974 return ret;
976 #endif /* HAVE_SET_RESTORE_SIGMASK */