From 4b481ba0edce396274abf5c91a62841888134dbb Mon Sep 17 00:00:00 2001
From: Hartmut Brandt <harti@FreeBSD.org>
Date: Wed, 1 Feb 2017 13:12:07 +0000
Subject: [PATCH] Merge filt_soread and filt_solisten and decide what to do
 when checking for EVFILT_READ at the point of the check not when the event is
 registers. This fixes a problem with asio when accepting a connection.

Reviewed by:	kib@, Scott Mitchell
---
 sys/kern/uipc_socket.c | 34 +++++++++-------------------------
 1 file changed, 9 insertions(+), 25 deletions(-)

diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index d7193d77f75a..c34e917b6bcb 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -159,16 +159,10 @@ static void	filt_sordetach(struct knote *kn);
 static int	filt_soread(struct knote *kn, long hint);
 static void	filt_sowdetach(struct knote *kn);
 static int	filt_sowrite(struct knote *kn, long hint);
-static int	filt_solisten(struct knote *kn, long hint);
 static int inline hhook_run_socket(struct socket *so, void *hctx, int32_t h_id);
 static int	filt_soempty(struct knote *kn, long hint);
 fo_kqfilter_t	soo_kqfilter;
 
-static struct filterops solisten_filtops = {
-	.f_isfd = 1,
-	.f_detach = filt_sordetach,
-	.f_event = filt_solisten,
-};
 static struct filterops soread_filtops = {
 	.f_isfd = 1,
 	.f_detach = filt_sordetach,
@@ -3107,10 +3101,7 @@ soo_kqfilter(struct file *fp, struct knote *kn)
 
 	switch (kn->kn_filter) {
 	case EVFILT_READ:
-		if (so->so_options & SO_ACCEPTCONN)
-			kn->kn_fop = &solisten_filtops;
-		else
-			kn->kn_fop = &soread_filtops;
+		kn->kn_fop = &soread_filtops;
 		sb = &so->so_rcv;
 		break;
 	case EVFILT_WRITE:
@@ -3321,6 +3312,11 @@ filt_soread(struct knote *kn, long hint)
 	struct socket *so;
 
 	so = kn->kn_fp->f_data;
+	if (so->so_options & SO_ACCEPTCONN) {
+		kn->kn_data = so->so_qlen;
+		return (!TAILQ_EMPTY(&so->so_comp));
+
+	}
 	SOCKBUF_LOCK_ASSERT(&so->so_rcv);
 
 	kn->kn_data = sbavail(&so->so_rcv) - so->so_rcv.sb_ctl;
@@ -3333,11 +3329,9 @@ filt_soread(struct knote *kn, long hint)
 
 	if (kn->kn_sfflags & NOTE_LOWAT) {
 		if (kn->kn_data >= kn->kn_sdata)
-			return 1;
-	} else {
-		if (sbavail(&so->so_rcv) >= so->so_rcv.sb_lowat)
-			return 1;
-	}
+			return (1);
+	} else if (sbavail(&so->so_rcv) >= so->so_rcv.sb_lowat)
+		return (1);
 
 	/* This hook returning non-zero indicates an event, not error */
 	return (hhook_run_socket(so, NULL, HHOOK_FILT_SOREAD));
@@ -3397,16 +3391,6 @@ filt_soempty(struct knote *kn, long hint)
 		return (0);
 }
 
-/*ARGSUSED*/
-static int
-filt_solisten(struct knote *kn, long hint)
-{
-	struct socket *so = kn->kn_fp->f_data;
-
-	kn->kn_data = so->so_qlen;
-	return (!TAILQ_EMPTY(&so->so_comp));
-}
-
 int
 socheckuid(struct socket *so, uid_t uid)
 {