+static inline void _scif_poll_wait(struct file *f, wait_queue_head_t *wq,
+ poll_table *p, struct scif_endpt *ep)
+{
+ /*
+ * Because poll_wait makes a GFP_KERNEL allocation, give up the lock
+ * and regrab it afterwards. Because the endpoint state might have
+ * changed while the lock was given up, the state must be checked
+ * again after re-acquiring the lock. The code in __scif_pollfd(..)
+ * does this.
+ */
+ spin_unlock(&ep->lock);
+ poll_wait(f, wq, p);
+ spin_lock(&ep->lock);
+}
+
+unsigned int
+__scif_pollfd(struct file *f, poll_table *wait, struct scif_endpt *ep)
+{
+ unsigned int mask = 0;
+
+ dev_dbg(scif_info.mdev.this_device,
+ "SCIFAPI pollfd: ep %p %s\n", ep, scif_ep_states[ep->state]);
+
+ spin_lock(&ep->lock);
+
+ /* Endpoint is waiting for a non-blocking connect to complete */
+ if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) {
+ _scif_poll_wait(f, &ep->conn_pend_wq, wait, ep);
+ if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) {
+ if (ep->state == SCIFEP_CONNECTED ||
+ ep->state == SCIFEP_DISCONNECTED ||
+ ep->conn_err)
+ mask |= POLLOUT;
+ goto exit;
+ }
+ }
+
+ /* Endpoint is listening for incoming connection requests */
+ if (ep->state == SCIFEP_LISTENING) {
+ _scif_poll_wait(f, &ep->conwq, wait, ep);
+ if (ep->state == SCIFEP_LISTENING) {
+ if (ep->conreqcnt)
+ mask |= POLLIN;
+ goto exit;
+ }
+ }
+
+ /* Endpoint is connected or disconnected */
+ if (ep->state == SCIFEP_CONNECTED || ep->state == SCIFEP_DISCONNECTED) {
+ if (poll_requested_events(wait) & POLLIN)
+ _scif_poll_wait(f, &ep->recvwq, wait, ep);
+ if (poll_requested_events(wait) & POLLOUT)
+ _scif_poll_wait(f, &ep->sendwq, wait, ep);
+ if (ep->state == SCIFEP_CONNECTED ||
+ ep->state == SCIFEP_DISCONNECTED) {
+ /* Data can be read without blocking */
+ if (scif_rb_count(&ep->qp_info.qp->inbound_q, 1))
+ mask |= POLLIN;
+ /* Data can be written without blocking */
+ if (scif_rb_space(&ep->qp_info.qp->outbound_q))
+ mask |= POLLOUT;
+ /* Return POLLHUP if endpoint is disconnected */
+ if (ep->state == SCIFEP_DISCONNECTED)
+ mask |= POLLHUP;
+ goto exit;
+ }
+ }
+
+ /* Return POLLERR if the endpoint is in none of the above states */
+ mask |= POLLERR;
+exit:
+ spin_unlock(&ep->lock);
+ return mask;
+}
+
+/**
+ * scif_poll() - Kernel mode SCIF poll
+ * @ufds: Array of scif_pollepd structures containing the end points
+ * and events to poll on
+ * @nfds: Size of the ufds array
+ * @timeout_msecs: Timeout in msecs, -ve implies infinite timeout
+ *
+ * The code flow in this function is based on do_poll(..) in select.c
+ *
+ * Returns the number of endpoints which have pending events or 0 in
+ * the event of a timeout. If a signal is used for wake up, -EINTR is
+ * returned.
+ */
+int
+scif_poll(struct scif_pollepd *ufds, unsigned int nfds, long timeout_msecs)
+{
+ struct poll_wqueues table;
+ poll_table *pt;
+ int i, mask, count = 0, timed_out = timeout_msecs == 0;
+ u64 timeout = timeout_msecs < 0 ? MAX_SCHEDULE_TIMEOUT
+ : msecs_to_jiffies(timeout_msecs);
+
+ poll_initwait(&table);
+ pt = &table.pt;
+ while (1) {
+ for (i = 0; i < nfds; i++) {
+ pt->_key = ufds[i].events | POLLERR | POLLHUP;
+ mask = __scif_pollfd(ufds[i].epd->anon,
+ pt, ufds[i].epd);
+ mask &= ufds[i].events | POLLERR | POLLHUP;
+ if (mask) {
+ count++;
+ pt->_qproc = NULL;
+ }
+ ufds[i].revents = mask;
+ }
+ pt->_qproc = NULL;
+ if (!count) {
+ count = table.error;
+ if (signal_pending(current))
+ count = -EINTR;
+ }
+ if (count || timed_out)
+ break;
+
+ if (!schedule_timeout_interruptible(timeout))
+ timed_out = 1;
+ }
+ poll_freewait(&table);
+ return count;
+}
+EXPORT_SYMBOL_GPL(scif_poll);
+