rsockets: Handle race between rshutdown and rpoll

Signed-off-by: Sean Hefty <sean.hefty@intel.com>

diff --git a/src/rsocket.c b/src/rsocket.c
index d544dd097cda228de114173c8fe569dc1881f057..f94ddf35a81fb20f608f753b1d7c003545294bde 100644 (file)
--- a/src/rsocket.c
+++ b/src/rsocket.c
@@ -1822,7 +1822,12 @@ static int rs_poll_cq(struct rsocket *rs)
                                        rs->state = rs_disconnected;
                                        return 0;
                                } else if (rs_msg_data(msg) == RS_CTRL_SHUTDOWN) {
-                                       rs->state &= ~rs_readable;
+                                       if (rs->state & rs_writable) {
+                                               rs->state &= ~rs_readable;
+                                       } else {
+                                               rs->state = rs_disconnected;
+                                               return 0;
+                                       }
                                }
                                break;
                        case RS_OP_WRITE:
@@ -2948,10 +2953,12 @@ static int rs_poll_events(struct pollfd *rfds, struct pollfd *fds, nfds_t nfds)
 
                rs = idm_lookup(&idm, fds[i].fd);
                if (rs) {
+                       fastlock_acquire(&rs->cq_wait_lock);
                        if (rs->type == SOCK_STREAM)
                                rs_get_cq_event(rs);
                        else
                                ds_get_cq_event(rs);
+                       fastlock_release(&rs->cq_wait_lock);
                        fds[i].revents = rs_poll_rs(rs, fds[i].events, 1, rs_poll_all);
                } else {
                        fds[i].revents = rfds[i].revents;
@@ -3098,7 +3105,8 @@ int rselect(int nfds, fd_set *readfds, fd_set *writefds,
 
 /*
  * For graceful disconnect, notify the remote side that we're
- * disconnecting and wait until all outstanding sends complete.
+ * disconnecting and wait until all outstanding sends complete, provided
+ * that the remote side has not sent a disconnect message.
  */
 int rshutdown(int socket, int how)
 {
@@ -3106,11 +3114,6 @@ int rshutdown(int socket, int how)
        int ctrl, ret = 0;
 
        rs = idm_at(&idm, socket);
-       if (how == SHUT_RD) {
-               rs->state &= ~rs_readable;
-               return 0;
-       }
-
        if (rs->fd_flags & O_NONBLOCK)
                rs_set_nonblocking(rs, 0);
 
@@ -3118,15 +3121,20 @@ int rshutdown(int socket, int how)
                if (how == SHUT_RDWR) {
                        ctrl = RS_CTRL_DISCONNECT;
                        rs->state &= ~(rs_readable | rs_writable);
-               } else {
+               } else if (how == SHUT_WR) {
                        rs->state &= ~rs_writable;
                        ctrl = (rs->state & rs_readable) ?
                                RS_CTRL_SHUTDOWN : RS_CTRL_DISCONNECT;
+               } else {
+                       rs->state &= ~rs_readable;
+                       if (rs->state & rs_writable)
+                               goto out;
+                       ctrl = RS_CTRL_DISCONNECT;
                }
                if (!rs->ctrl_avail) {
                        ret = rs_process_cq(rs, 0, rs_conn_can_send_ctrl);
                        if (ret)
-                               return ret;
+                               goto out;
                }
 
                if ((rs->state & rs_connected) && rs->ctrl_avail) {
@@ -3138,10 +3146,17 @@ int rshutdown(int socket, int how)
        if (rs->state & rs_connected)
                rs_process_cq(rs, 0, rs_conn_all_sends_done);
 
+out:
        if ((rs->fd_flags & O_NONBLOCK) && (rs->state & rs_connected))
                rs_set_nonblocking(rs, rs->fd_flags);
 
-       return 0;
+       if (rs->state & rs_disconnected) {
+               /* Generate event by flushing receives to unblock rpoll */
+               ibv_req_notify_cq(rs->cm_id->recv_cq, 0);
+               rdma_disconnect(rs->cm_id);
+       }
+
+       return ret;
 }
 
 static void ds_shutdown(struct rsocket *rs)