From: dlg <dlg@openbsd.org>
Date: Sun, 13 Jul 2014 09:52:48 +0000 (+0000)
Subject: treat external storage allocated by the mbuf layer the same as
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=2486872ac446a3cc4596a6daba574f3b7bbbed9f;p=openbsd

treat external storage allocated by the mbuf layer the same as
external storage attached to an mbuf anywhere else. this means it
uses MEXTADD to wire it up to the mbuf, and it relies on the ext_free
and ext_arg bits in the header to call the right free function
against the right pool.

M_CLUSTER gets renamed to M_EXTWR. the type field in MEXTADD gets
reused as a flags field so anything attaching storage to an mbuf
can say if it is writable or not.

ok claudio@
---

diff --git a/share/man/man9/mbuf.9 b/share/man/man9/mbuf.9
index ae4cde5f5d8..52a1c98375c 100644
--- a/share/man/man9/mbuf.9
+++ b/share/man/man9/mbuf.9
@@ -1,4 +1,4 @@
-.\"     $OpenBSD: mbuf.9,v 1.73 2014/07/13 05:23:24 dlg Exp $
+.\"     $OpenBSD: mbuf.9,v 1.74 2014/07/13 09:52:48 dlg Exp $
 .\"
 .\" Copyright (c) 2001 Jean-Jacques Bernard-Gundol <jjbg@openbsd.org>
 .\" All rights reserved.
@@ -83,7 +83,7 @@
 .Fn MCLGET "struct mbuf *m" "int how"
 .Ft struct mbuf *
 .Fn MCLGETI "struct mbuf *m" "int how" "struct ifnet *ifp" "int len"
-.Fn MEXTADD "struct mbuf *m" "caddr_t buf" "u_int size" "int type" \
+.Fn MEXTADD "struct mbuf *m" "caddr_t buf" "u_int size" "int flags" \
 "void (*free)(caddr_t, u_int, void *)" "void *arg"
 .Fn M_ALIGN "struct mbuf *m" "int len"
 .Fn MH_ALIGN "struct mbuf *m" "int len"
@@ -636,11 +636,12 @@ See
 .Fn m_get
 for a description of
 .Fa how .
-.It Fn MEXTADD "struct mbuf *m" "caddr_t buf" "u_int size" "int type" \
+.It Fn MEXTADD "struct mbuf *m" "caddr_t buf" "u_int size" "int flags" \
 "void (*free)(caddr_t, u_int, void *)" "void *arg"
 Add pre-allocated storage to the mbuf pointed to by
 .Fa m .
-On success, the flag M_EXT is set in the mbuf.
+On success, the flag M_EXT is set in the mbuf, and M_EXTWR if specified in
+.Fa flags ..
 .It Fn M_ALIGN "struct mbuf *m" "int len"
 Set the
 .Fa m_data
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index a2dcf8af65a..c985968e29e 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_mbuf.c,v 1.190 2014/07/09 13:05:45 dlg Exp $	*/
+/*	$OpenBSD: uipc_mbuf.c,v 1.191 2014/07/13 09:52:48 dlg Exp $	*/
 /*	$NetBSD: uipc_mbuf.c,v 1.15.4.1 1996/06/13 17:11:44 cgd Exp $	*/
 
 /*
@@ -112,7 +112,7 @@ u_int	mclsizes[] = {
 static	char mclnames[MCLPOOLS][8];
 struct	pool mclpools[MCLPOOLS];
 
-int	m_clpool(u_int);
+struct pool *m_clpool(u_int);
 
 int max_linkhdr;		/* largest link-level header */
 int max_protohdr;		/* largest protocol header */
@@ -278,29 +278,32 @@ m_getclr(int nowait, int type)
 	return (m);
 }
 
-int
+struct pool *
 m_clpool(u_int pktlen)
 {
+	struct pool *pp;
 	int pi;
 
-	for (pi = 0; pi < MCLPOOLS; pi++) {
-		if (pktlen <= mclsizes[pi])
-			return (pi);
+	for (pi = 0; pi < nitems(mclpools); pi++) {
+		pp = &mclpools[pi];
+		if (pktlen <= pp->pr_size)
+			return (pp);
 	}
 
-	return (-1);
+	return (NULL);
 }
 
 struct mbuf *
 m_clget(struct mbuf *m, int how, struct ifnet *ifp, u_int pktlen)
 {
 	struct mbuf *m0 = NULL;
-	int pi;
+	struct pool *pp;
+	caddr_t buf;
 	int s;
 
-	pi = m_clpool(pktlen);
+	pp = m_clpool(pktlen);
 #ifdef DIAGNOSTIC
-	if (pi == -1)
+	if (pp == NULL)
 		panic("m_clget: request for %u byte cluster", pktlen);
 #endif
 
@@ -313,9 +316,8 @@ m_clget(struct mbuf *m, int how, struct ifnet *ifp, u_int pktlen)
 		}
 		m = m0;
 	}
-	m->m_ext.ext_buf = pool_get(&mclpools[pi],
-	    how == M_WAIT ? PR_WAITOK : PR_NOWAIT);
-	if (!m->m_ext.ext_buf) {
+	buf = pool_get(pp, how == M_WAIT ? PR_WAITOK : PR_NOWAIT);
+	if (buf == NULL) {
 		if (m0)
 			m_freem(m0);
 		splx(s);
@@ -323,15 +325,17 @@ m_clget(struct mbuf *m, int how, struct ifnet *ifp, u_int pktlen)
 	}
 	splx(s);
 
-	m->m_data = m->m_ext.ext_buf;
-	m->m_flags |= M_EXT|M_CLUSTER;
-	m->m_ext.ext_size = mclpools[pi].pr_size;
-	m->m_ext.ext_free = NULL;
-	m->m_ext.ext_arg = &mclpools[pi];
-	MCLINITREFERENCE(m);
+	MEXTADD(m, buf, pp->pr_size, M_EXTWR, m_extfree_pool, pp);
 	return (m);
 }
 
+void
+m_extfree_pool(caddr_t buf, u_int size, void *pp)
+{
+	splassert(IPL_NET);
+	pool_put(pp, buf);
+}
+
 struct mbuf *
 m_free_unlocked(struct mbuf *m)
 {
@@ -375,15 +379,13 @@ m_extfree(struct mbuf *m)
 		    m->m_ext.ext_prevref;
 		m->m_ext.ext_prevref->m_ext.ext_nextref =
 		    m->m_ext.ext_nextref;
-	} else if (m->m_flags & M_CLUSTER) {
-		pool_put(m->m_ext.ext_arg, m->m_ext.ext_buf);
 	} else if (m->m_ext.ext_free)
 		(*(m->m_ext.ext_free))(m->m_ext.ext_buf,
 		    m->m_ext.ext_size, m->m_ext.ext_arg);
 	else
 		panic("unknown type of extension buffer");
 	m->m_ext.ext_size = 0;
-	m->m_flags &= ~(M_EXT|M_CLUSTER);
+	m->m_flags &= ~(M_EXT|M_EXTWR);
 }
 
 void
@@ -449,7 +451,7 @@ m_defrag(struct mbuf *m, int how)
 	if (m0->m_flags & M_EXT) {
 		memcpy(&m->m_ext, &m0->m_ext, sizeof(struct mbuf_ext));
 		MCLINITREFERENCE(m);
-		m->m_flags |= M_EXT|M_CLUSTER;
+		m->m_flags |= m0->m_flags & (M_EXT|M_EXTWR);
 		m->m_data = m->m_ext.ext_buf;
 	} else {
 		m->m_data = m->m_pktdat;
@@ -457,7 +459,7 @@ m_defrag(struct mbuf *m, int how)
 	}
 	m->m_pkthdr.len = m->m_len = m0->m_len;
 
-	m0->m_flags &= ~(M_EXT|M_CLUSTER);	/* cluster is gone */
+	m0->m_flags &= ~(M_EXT|M_EXTWR);	/* cluster is gone */
 	m_free(m0);
 
 	return (0);
@@ -1186,7 +1188,7 @@ m_dup_pkthdr(struct mbuf *to, struct mbuf *from, int wait)
 
 	KASSERT(from->m_flags & M_PKTHDR);
 
-	to->m_flags = (to->m_flags & (M_EXT | M_CLUSTER));
+	to->m_flags = (to->m_flags & (M_EXT | M_EXTWR));
 	to->m_flags |= (from->m_flags & M_COPYFLAGS);
 	to->m_pkthdr = from->m_pkthdr;
 
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index cff349331fa..bedfdfe38a4 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mbuf.h,v 1.179 2014/07/09 13:05:45 dlg Exp $	*/
+/*	$OpenBSD: mbuf.h,v 1.180 2014/07/13 09:52:48 dlg Exp $	*/
 /*	$NetBSD: mbuf.h,v 1.19 1996/02/09 18:25:14 christos Exp $	*/
 
 /*
@@ -167,7 +167,7 @@ struct mbuf {
 #define	M_EXT		0x0001	/* has associated external storage */
 #define	M_PKTHDR	0x0002	/* start of record */
 #define	M_EOR		0x0004	/* end of record */
-#define M_CLUSTER	0x0008	/* external storage is a cluster */
+#define M_EXTWR		0x0008	/* external storage is writable */
 #define	M_PROTO1	0x0010	/* protocol-specific */
 
 /* mbuf pkthdr flags, also in m_flags */
@@ -185,7 +185,7 @@ struct mbuf {
 
 #ifdef _KERNEL
 #define M_BITS \
-    ("\20\1M_EXT\2M_PKTHDR\3M_EOR\4M_CLUSTER\5M_PROTO1\6M_VLANTAG\7M_LOOP" \
+    ("\20\1M_EXT\2M_PKTHDR\3M_EOR\4M_EXTWR\5M_PROTO1\6M_VLANTAG\7M_LOOP" \
     "\10M_FILDROP\11M_BCAST\12M_MCAST\13M_CONF\14M_AUTH\15M_TUNNEL" \
     "\16M_ZEROIZE\17M_COMP\20M_LINK0")
 #endif
@@ -267,7 +267,7 @@ struct mbuf {
 
 #define	MCLADDREFERENCE(o, n)	do {					\
 		int ms = splnet();					\
-		(n)->m_flags |= ((o)->m_flags & (M_EXT|M_CLUSTER));	\
+		(n)->m_flags |= ((o)->m_flags & (M_EXT|M_EXTWR));	\
 		(n)->m_ext.ext_nextref = (o)->m_ext.ext_nextref;	\
 		(n)->m_ext.ext_prevref = (o);				\
 		(o)->m_ext.ext_nextref = (n);				\
@@ -292,10 +292,9 @@ struct mbuf {
  * MCLGET allocates and adds an mbuf cluster to a normal mbuf;
  * the flag M_EXT is set upon success.
  */
-#define	MEXTADD(m, buf, size, type, free, arg) do {			\
+#define	MEXTADD(m, buf, size, mflags, free, arg) do {			\
 	(m)->m_data = (m)->m_ext.ext_buf = (caddr_t)(buf);		\
-	(m)->m_flags |= M_EXT;						\
-	(m)->m_flags &= ~M_CLUSTER;					\
+	(m)->m_flags |= M_EXT | (mflags & M_EXTWR);			\
 	(m)->m_ext.ext_size = (size);					\
 	(m)->m_ext.ext_free = (free);					\
 	(m)->m_ext.ext_arg = (arg);					\
@@ -327,7 +326,7 @@ struct mbuf {
  * from must have M_PKTHDR set, and to must be empty.
  */
 #define	M_MOVE_PKTHDR(to, from) do {					\
-	(to)->m_flags = ((to)->m_flags & (M_EXT | M_CLUSTER));		\
+	(to)->m_flags = ((to)->m_flags & (M_EXT | M_EXTWR));		\
 	(to)->m_flags |= (from)->m_flags & M_COPYFLAGS;			\
 	M_MOVE_HDR((to), (from));					\
 	if (((to)->m_flags & M_EXT) == 0)				\
@@ -354,7 +353,7 @@ struct mbuf {
  */
 #define	M_READONLY(m)							\
 	(((m)->m_flags & M_EXT) != 0 &&					\
-	  (((m)->m_flags & M_CLUSTER) == 0 || MCLISREFERENCED(m)))
+	  (((m)->m_flags & M_EXTWR) == 0 || MCLISREFERENCED(m)))
 
 /*
  * Compute the amount of space available
@@ -428,6 +427,7 @@ struct  mbuf *m_getptr(struct mbuf *, int, int *);
 int	m_leadingspace(struct mbuf *);
 int	m_trailingspace(struct mbuf *);
 struct mbuf *m_clget(struct mbuf *, int, struct ifnet *, u_int);
+void	m_extfree_pool(caddr_t, u_int, void *);
 void	m_adj(struct mbuf *, int);
 int	m_copyback(struct mbuf *, int, int, const void *, int);
 void	m_freem(struct mbuf *);