fd_set __user *exp, s64 *timeout)
{
fd_set_bits fds;
- char *bits;
- int ret, size, max_fdset;
+ void *bits;
+ int ret, max_fdset;
+ unsigned int size;
struct fdtable *fdt;
/* Allocate small arguments on the stack to save memory and be faster */
- char stack_fds[SELECT_STACK_ALLOC];
+ long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
ret = -EINVAL;
if (n < 0)
* since we used fdset we need to allocate memory in units of
* long-words.
*/
- ret = -ENOMEM;
size = FDS_BYTES(n);
- if (6*size < SELECT_STACK_ALLOC)
- bits = stack_fds;
- else
+ bits = stack_fds;
+ if (size > sizeof(stack_fds) / 6) {
+ /* Not enough space in on-stack array; must use kmalloc */
+ ret = -ENOMEM;
bits = kmalloc(6 * size, GFP_KERNEL);
- if (!bits)
- goto out_nofds;
- fds.in = (unsigned long *) bits;
- fds.out = (unsigned long *) (bits + size);
- fds.ex = (unsigned long *) (bits + 2*size);
- fds.res_in = (unsigned long *) (bits + 3*size);
- fds.res_out = (unsigned long *) (bits + 4*size);
- fds.res_ex = (unsigned long *) (bits + 5*size);
+ if (!bits)
+ goto out_nofds;
+ }
+ fds.in = bits;
+ fds.out = bits + size;
+ fds.ex = bits + 2*size;
+ fds.res_in = bits + 3*size;
+ fds.res_out = bits + 4*size;
+ fds.res_ex = bits + 5*size;
if ((ret = get_fd_set(n, inp, fds.in)) ||
(ret = get_fd_set(n, outp, fds.out)) ||
#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
-static void do_pollfd(unsigned int num, struct pollfd * fdpage,
- poll_table ** pwait, int *count)
+/*
+ * Fish for pollable events on the pollfd->fd file descriptor. We're only
+ * interested in events matching the pollfd->events mask, and the result
+ * matching that mask is both recorded in pollfd->revents and returned. The
+ * pwait poll_table will be used by the fd-provided poll handler for waiting,
+ * if non-NULL.
+ */
+static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
{
- int i;
-
- for (i = 0; i < num; i++) {
- int fd;
- unsigned int mask;
- struct pollfd *fdp;
-
- mask = 0;
- fdp = fdpage+i;
- fd = fdp->fd;
- if (fd >= 0) {
- int fput_needed;
- struct file * file = fget_light(fd, &fput_needed);
- mask = POLLNVAL;
- if (file != NULL) {
- mask = DEFAULT_POLLMASK;
- if (file->f_op && file->f_op->poll)
- mask = file->f_op->poll(file, *pwait);
- mask &= fdp->events | POLLERR | POLLHUP;
- fput_light(file, fput_needed);
- }
- if (mask) {
- *pwait = NULL;
- (*count)++;
- }
+ unsigned int mask;
+ int fd;
+
+ mask = 0;
+ fd = pollfd->fd;
+ if (fd >= 0) {
+ int fput_needed;
+ struct file * file;
+
+ file = fget_light(fd, &fput_needed);
+ mask = POLLNVAL;
+ if (file != NULL) {
+ mask = DEFAULT_POLLMASK;
+ if (file->f_op && file->f_op->poll)
+ mask = file->f_op->poll(file, pwait);
+ /* Mask out unneeded events. */
+ mask &= pollfd->events | POLLERR | POLLHUP;
+ fput_light(file, fput_needed);
}
- fdp->revents = mask;
}
+ pollfd->revents = mask;
+
+ return mask;
}
static int do_poll(unsigned int nfds, struct poll_list *list,
long __timeout;
set_current_state(TASK_INTERRUPTIBLE);
- walk = list;
- while(walk != NULL) {
- do_pollfd( walk->len, walk->entries, &pt, &count);
- walk = walk->next;
+ for (walk = list; walk != NULL; walk = walk->next) {
+ struct pollfd * pfd, * pfd_end;
+
+ pfd = walk->entries;
+ pfd_end = pfd + walk->len;
+ for (; pfd != pfd_end; pfd++) {
+ /*
+ * Fish for events. If we found one, record it
+ * and kill the poll_table, 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)) {
+ count++;
+ pt = NULL;
+ }
+ }
}
+ /*
+ * All waiters have already been registered, so don't provide
+ * a poll_table to them on the next loop iteration.
+ */
pt = NULL;
if (count || !*timeout || signal_pending(current))
break;
struct poll_list *walk;
struct fdtable *fdt;
int max_fdset;
- /* Allocate small arguments on the stack to save memory and be faster */
- char stack_pps[POLL_STACK_ALLOC];
+ /* Allocate small arguments on the stack to save memory and be
+ faster - use long to make sure the buffer is aligned properly
+ on 64 bit archs to avoid unaligned access */
+ long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
struct poll_list *stack_pp = NULL;
/* Do a sanity check on nfds ... */
asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
long timeout_msecs)
{
- s64 timeout_jiffies = 0;
+ s64 timeout_jiffies;
- if (timeout_msecs) {
+ if (timeout_msecs > 0) {
#if HZ > 1000
/* We can only overflow if HZ > 1000 */
if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ)
else
#endif
timeout_jiffies = msecs_to_jiffies(timeout_msecs);
+ } else {
+ /* Infinite (< 0) or no (0) timeout */
+ timeout_jiffies = timeout_msecs;
}
return do_sys_poll(ufds, nfds, &timeout_jiffies);
git.openpandora.org / pandora-kernel.git / blobdiff