Lock down a socket, milestone 1.

o Add a mutex (sb_mtx) to struct sockbuf. This protects the data in a
  socket buffer. The mutex in the receive buffer also protects the data
  in struct socket.

o Determine the lock strategy for each members in struct socket.

o Lock down the following members:

  - so_count
  - so_options
  - so_linger
  - so_state

o Remove *_locked() socket APIs.  Make the following socket APIs
  touching the members above now require a locked socket:

 - sodisconnect()
 - soisconnected()
 - soisconnecting()
 - soisdisconnected()
 - soisdisconnecting()
 - sofree()
 - soref()
 - sorele()
 - sorwakeup()
 - sotryfree()
 - sowakeup()
 - sowwakeup()

Reviewed by:	alfred

1 files changed, 5 insertions, 2 deletions

diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index 15837d3..8a6176d 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -1777,19 +1777,22 @@ fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp)
 		*spp = (struct socket *)fp->f_data;
 		if (fflagp)
 			*fflagp = fp->f_flag;
+		SOCK_LOCK(*spp);
 		soref(*spp);
+		SOCK_UNLOCK(*spp);
 	}
 	FILEDESC_UNLOCK(td->td_proc->p_fd);
 	return(error);
 }
 
 /*
- * Drop the reference count on the the socket and XXX release the SX lock in
- * the future.  The last reference closes the socket.
+ * Drop the reference count on the the socket and release the lock.
+ * The last reference closes the socket.  The socket must be unlocked.
  */
 void
 fputsock(struct socket *so)
 {
+	SOCK_LOCK(so);
 	sorele(so);
 }