int do_select(int n, fd_set_bits *fds, long *timeout) { struct poll_wqueues table; poll_table *wait; int retval, i; long __timeout = *timeout; spin_lock(¤t->files->file_lock); retval = max_select_fd(n, fds); spin_unlock(¤t->files->file_lock); if (retval < 0) return retval; n = retval; poll_initwait(&table); wait = &table.pt; if (!__timeout) wait = NULL; retval = 0; for (;;) { unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; set_current_state(TASK_INTERRUPTIBLE); inp = fds->in; outp = fds->out; exp = fds->ex; rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; for (i = 0; i < n; ++rinp, ++routp, ++rexp) { unsigned long in, out, ex, all_bits, bit = 1, mask, j; unsigned long res_in = 0, res_out = 0, res_ex = 0; struct file_operations *f_op = NULL; struct file *file = NULL; in = *inp++; out = *outp++; ex = *exp++; all_bits = in | out | ex; if (all_bits == 0) { i += __NFDBITS; continue; } for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) { if (i >= n) break; if (!(bit & all_bits)) continue; file = fget(i); if (file) { f_op = file->f_op; mask = DEFAULT_POLLMASK; if (f_op && f_op->poll) mask = (*f_op->poll)(file, retval ? NULL : wait); fput(file); if ((mask & POLLIN_SET) && (in & bit)) { res_in |= bit; retval++; } if ((mask & POLLOUT_SET) && (out & bit)) { res_out |= bit; retval++; } if ((mask & POLLEX_SET) && (ex & bit)) { res_ex |= bit; retval++; } } cond_resched(); } if (res_in) *rinp = res_in; if (res_out) *routp = res_out; if (res_ex) *rexp = res_ex; } wait = NULL; if (retval || !__timeout || signal_pending(current)) break; if(table.error) { retval = table.error; break; } __timeout = schedule_timeout(__timeout); } __set_current_state(TASK_RUNNING); poll_freewait(&table); /* * Up-to-date the caller timeout. */ *timeout = __timeout; return retval; }
int do_select(int n, fd_set_bits *fds, long *timeout) { poll_table table, *wait; int retval, i, off; long __timeout = *timeout; read_lock(¤t->files->file_lock); retval = max_select_fd(n, fds); read_unlock(¤t->files->file_lock); if (retval < 0) return retval; n = retval; poll_initwait(&table); wait = &table; if (!__timeout) wait = NULL; retval = 0; for (;;) { set_current_state(TASK_INTERRUPTIBLE); for (i = 0 ; i < n; i++) { unsigned long bit = BIT(i); unsigned long mask; struct file *file; off = i / __NFDBITS; if (!(bit & BITS(fds, off))) continue; file = fget(i); mask = POLLNVAL; if (file) { mask = DEFAULT_POLLMASK; if (file->f_op && file->f_op->poll) mask = file->f_op->poll(file, wait); fput(file); } if ((mask & POLLIN_SET) && ISSET(bit, __IN(fds,off))) { SET(bit, __RES_IN(fds,off)); retval++; wait = NULL; } if ((mask & POLLOUT_SET) && ISSET(bit, __OUT(fds,off))) { SET(bit, __RES_OUT(fds,off)); retval++; wait = NULL; } if ((mask & POLLEX_SET) && ISSET(bit, __EX(fds,off))) { SET(bit, __RES_EX(fds,off)); retval++; wait = NULL; } } wait = NULL; if (retval || !__timeout || signal_pending(current)) break; if(table.error) { retval = table.error; break; } __timeout = schedule_timeout(__timeout); } current->state = TASK_RUNNING; poll_freewait(&table); /* * Up-to-date the caller timeout. */ *timeout = __timeout; return retval; }