First rev at making pipe(2) pipe's MPsafe.

Both ends of the pipe share a pool_mutex, this makes allocation
and deadlock avoidance easy.

Remove some un-needed FILE_LOCK ops while I'm here.

There are some issues wrt to select and the f{s,g}etown code that
we'll have to deal with, I think we may also need to move the calls
to vfs_timestamp outside of the sections covered by PIPE_LOCK.

1 files changed, 8 insertions, 1 deletions

diff --git a/sys/sys/pipe.h b/sys/sys/pipe.h
index 2a1f3d4..f226396 100644
--- a/sys/sys/pipe.h
+++ b/sys/sys/pipe.h
@@ -86,7 +86,7 @@ struct pipemapping {
 #define PIPE_WANT	0x020	/* Pipe is wanted to be run-down. */
 #define PIPE_SEL	0x040	/* Pipe has a select active. */
 #define PIPE_EOF	0x080	/* Pipe is in EOF condition. */
-#define PIPE_LOCK	0x100	/* Process has exclusive access to pointers/data. */
+#define PIPE_LOCKFL	0x100	/* Process has exclusive access to pointers/data. */
 #define PIPE_LWANT	0x200	/* Process wants exclusive access to pointers/data. */
 #define PIPE_DIRECTW	0x400	/* Pipe direct write active. */
 #define PIPE_DIRECTOK	0x800	/* Direct mode ok. */
@@ -106,6 +106,13 @@ struct pipe {
 	struct	pipe *pipe_peer;	/* link with other direction */
 	u_int	pipe_state;		/* pipe status info */
 	int	pipe_busy;		/* busy flag, mostly to handle rundown sanely */
+	struct	mtx *pipe_mtxp;		/* shared mutex between both pipes */
 };
 
+#define PIPE_MTX(pipe)		(pipe)->pipe_mtxp
+#define PIPE_LOCK(pipe)		mtx_lock(PIPE_MTX(pipe))
+#define PIPE_UNLOCK(pipe)	mtx_unlock(PIPE_MTX(pipe))
+#define PIPE_LOCK_ASSERT(pipe, type)  mtx_assert(PIPE_MTX(pipe), (type))
+
+
 #endif /* !_SYS_PIPE_H_ */