- Fix ncp_poll() to not panic if the socket doesn't have any pending data.

  We have to adjust curthread's state enough so that it appears to be
  in a poll(2) or select(2) call so that selrecord() will work and then
  teardown that state after calling sopoll().
- Fix some minor nits in nearby ncp_sock_rselect() and in the identical
  nbssn_rselect() function in the netsmb code:
  - Don't call nb_poll()/ncp_poll() now that ncp_poll() already fakes up
    poll(2) state since the rselect() functions already do that.  Just
    invoke sopoll() directly.
  - To make things slightly more intuitive, store the results of sopoll()
    in a new 'revents' variable rather than 'error' since that's what
    sopoll() actually returns.
  - If the requested timeout time has been exceeded by the time we get
    ready to block, then return EWOULDBLOCK rather than 0 to signal a
    timeout as this is what the calling code expects.

Tested by:	Eric Christeson <eric.j.christeson AT gmail> (1)
MFC after:	1 week

1 files changed, 6 insertions, 10 deletions

diff --git a/sys/netsmb/smb_trantcp.c b/sys/netsmb/smb_trantcp.c
index 4c273cd..5db6b7e 100644
--- a/sys/netsmb/smb_trantcp.c
+++ b/sys/netsmb/smb_trantcp.c
@@ -94,18 +94,12 @@ nb_setsockopt_int(struct socket *so, int level, int name, int val)
 	return sosetopt(so, &sopt);
 }
 
-static __inline int
-nb_poll(struct nbpcb *nbp, int events, struct thread *td)
-{
-	return sopoll(nbp->nbp_tso, events, NULL, td);
-}
-
 static int
 nbssn_rselect(struct nbpcb *nbp, struct timeval *tv, int events,
 	struct thread *td)
 {
 	struct timeval atv, rtv, ttv;
-	int ncoll, timo, error;
+	int ncoll, timo, error, revents;
 
 	if (tv) {
 		atv = *tv;
@@ -128,16 +122,18 @@ retry:
 
 	/* XXX: Should be done when the thread is initialized. */
 	TAILQ_INIT(&td->td_selq);
-	error = nb_poll(nbp, events, td);
+	revents = sopoll(nbp->nbp_tso, events, NULL, td);
 	mtx_lock(&sellock);
-	if (error) {
+	if (revents) {
 		error = 0;
 		goto done;
 	}
 	if (tv) {
 		getmicrouptime(&rtv);
-		if (timevalcmp(&rtv, &atv, >=))
+		if (timevalcmp(&rtv, &atv, >=)) {
+			error = EWOULDBLOCK;
 			goto done;
+		}
 		ttv = atv;
 		timevalsub(&ttv, &rtv);
 		timo = tvtohz(&ttv);