Merge additional socket buffer locking from rwatson_netperf:

- Lock down low hanging fruit use of sb_flags with socket buffer
  lock.

- Lock down low hanging fruit use of so_state with socket lock.

- Lock down low hanging fruit use of so_options.

- Lock down low-hanging fruit use of sb_lowwat and sb_hiwat with
  socket buffer lock.

- Annotate situations in which we unlock the socket lock and then
  grab the receive socket buffer lock, which are currently actually
  the same lock.  Depending on how we want to play our cards, we
  may want to coallesce these lock uses to reduce overhead.

- Convert a if()->panic() into a KASSERT relating to so_state in
  soaccept().

- Remove a number of splnet()/splx() references.

More complex merging of socket and socket buffer locking to
follow.

1 files changed, 20 insertions, 0 deletions

diff --git a/sys/kern/sys_socket.c b/sys/kern/sys_socket.c
index a580b43..986edf7 100644
--- a/sys/kern/sys_socket.c
+++ b/sys/kern/sys_socket.c
@@ -131,21 +131,41 @@ soo_ioctl(fp, cmd, data, active_cred, td)
 	switch (cmd) {
 
 	case FIONBIO:
+		SOCK_LOCK(so);
 		if (*(int *)data)
 			so->so_state |= SS_NBIO;
 		else
 			so->so_state &= ~SS_NBIO;
+		SOCK_UNLOCK(so);
 		return (0);
 
 	case FIOASYNC:
+		/*
+		 * XXXRW: This code separately acquires SOCK_LOCK(so)
+		 * and SOCKBUF_LOCK(&so->so_rcv) even though they are
+		 * the same mutex to avoid introducing the assumption
+		 * that they are the same.
+		 */
 		if (*(int *)data) {
+			SOCK_LOCK(so);
 			so->so_state |= SS_ASYNC;
+			SOCK_UNLOCK(so);
+			SOCKBUF_LOCK(&so->so_rcv);
 			so->so_rcv.sb_flags |= SB_ASYNC;
+			SOCKBUF_UNLOCK(&so->so_rcv);
+			SOCKBUF_LOCK(&so->so_snd);
 			so->so_snd.sb_flags |= SB_ASYNC;
+			SOCKBUF_UNLOCK(&so->so_snd);
 		} else {
+			SOCK_LOCK(so);
 			so->so_state &= ~SS_ASYNC;
+			SOCK_UNLOCK(so);
+			SOCKBUF_LOCK(&so->so_rcv);
 			so->so_rcv.sb_flags &= ~SB_ASYNC;
+			SOCKBUF_UNLOCK(&so->so_rcv);
+			SOCKBUF_LOCK(&so->so_snd);
 			so->so_snd.sb_flags &= ~SB_ASYNC;
+			SOCKBUF_UNLOCK(&so->so_snd);
 		}
 		return (0);