git: 97cf43ebc5c9 - main - socket: Reorder socket and sockbuf fields to eliminate some padding

[Mark Johnston]

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=97cf43ebc5c9cd4b43190ba2b1ff3d0e0f9372cc

commit 97cf43ebc5c9cd4b43190ba2b1ff3d0e0f9372cc
Author:     Mark Johnston <markj at FreeBSD.org>
AuthorDate: 2021-09-07 18:45:22 +0000
Commit:     Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-09-07 18:59:24 +0000

    socket: Reorder socket and sockbuf fields to eliminate some padding
    
    This is in preparation for moving sockbuf locks into the owning socket,
    in order to provide proper interlocking for listen(2).  In particular,
    listening sockets do not use the socket buffers and repurpose that space
    in struct socket for their own purposes.  Moving the locks out of the
    socket buffers and into the socket proper makes it possible to safely
    lock socket buffers and test for a listening socket before deciding how
    to proceed.
    
    Reordering these fields saves some space and helps ensure that UMA will
    provide the same space efficiency for sockets as before.  No functional
    change intended.
    
    Reviewed by:    tuexen, gallatin
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D31656
---
 sys/sys/sockbuf.h   | 4 ++--
 sys/sys/socketvar.h | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/sys/sys/sockbuf.h b/sys/sys/sockbuf.h
index 4c56f4eaf234..e7a4c8883054 100644
--- a/sys/sys/sockbuf.h
+++ b/sys/sys/sockbuf.h
@@ -85,7 +85,8 @@ struct	sockbuf {
 	struct	sx sb_sx;		/* prevent I/O interlacing */
 	struct	selinfo *sb_sel;	/* process selecting read/write */
 	short	sb_state;	/* (a) socket state on sockbuf */
-#define	sb_startzero	sb_mb
+#define	sb_startzero	sb_flags
+	short	sb_flags;	/* (a) flags, see above */
 	struct	mbuf *sb_mb;	/* (a) the mbuf chain */
 	struct	mbuf *sb_mbtail; /* (a) the last mbuf in the chain */
 	struct	mbuf *sb_lastrecord;	/* (a) first mbuf of last
@@ -109,7 +110,6 @@ struct	sockbuf {
 	struct	ktls_session *sb_tls_info; /* (a + b) TLS state */
 	struct	mbuf *sb_mtls;	/* (a) TLS mbuf chain */
 	struct	mbuf *sb_mtlstail; /* (a) last mbuf in TLS chain */
-	short	sb_flags;	/* (a) flags, see above */
 	int	(*sb_upcall)(struct socket *, void *, int); /* (a) */
 	void	*sb_upcallarg;	/* (a) */
 	TAILQ_HEAD(, kaiocb) sb_aiojobq; /* (a) pending AIO ops */
diff --git a/sys/sys/socketvar.h b/sys/sys/socketvar.h
index 47033fdabbfa..506a328b1e0a 100644
--- a/sys/sys/socketvar.h
+++ b/sys/sys/socketvar.h
@@ -91,13 +91,13 @@ struct socket {
 	volatile u_int	so_count;	/* (b / refcount) */
 	struct selinfo	so_rdsel;	/* (b/cr) for so_rcv/so_comp */
 	struct selinfo	so_wrsel;	/* (b/cs) for so_snd */
-	short	so_type;		/* (a) generic type, see socket.h */
 	int	so_options;		/* (b) from socket call, see socket.h */
-	short	so_linger;		/* time to linger close(2) */
+	short	so_type;		/* (a) generic type, see socket.h */
 	short	so_state;		/* (b) internal state flags SS_* */
 	void	*so_pcb;		/* protocol control block */
 	struct	vnet *so_vnet;		/* (a) network stack instance */
 	struct	protosw *so_proto;	/* (a) protocol handle */
+	short	so_linger;		/* time to linger close(2) */
 	short	so_timeo;		/* (g) connection timeout */
 	u_short	so_error;		/* (f) error affecting connection */
 	u_short so_rerror;		/* (f) error affecting connection */