Module Name: src
Committed By: maxv
Date: Mon Jan 22 15:05:28 UTC 2018
Modified Files:
src/sys/kern: uipc_mbuf.c
Log Message:
Style and clarify.
To generate a diff of this commit:
cvs rdiff -u -r1.180 -r1.181 src/sys/kern/uipc_mbuf.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/uipc_mbuf.c
diff -u src/sys/kern/uipc_mbuf.c:1.180 src/sys/kern/uipc_mbuf.c:1.181
--- src/sys/kern/uipc_mbuf.c:1.180 Mon Jan 22 10:26:38 2018
+++ src/sys/kern/uipc_mbuf.c Mon Jan 22 15:05:27 2018
@@ -1,4 +1,4 @@
-/* $NetBSD: uipc_mbuf.c,v 1.180 2018/01/22 10:26:38 maxv Exp $ */
+/* $NetBSD: uipc_mbuf.c,v 1.181 2018/01/22 15:05:27 maxv Exp $ */
/*
* Copyright (c) 1999, 2001 The NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uipc_mbuf.c,v 1.180 2018/01/22 10:26:38 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uipc_mbuf.c,v 1.181 2018/01/22 15:05:27 maxv Exp $");
#ifdef _KERNEL_OPT
#include "opt_mbuftrace.h"
@@ -103,7 +103,7 @@ static void sysctl_kern_mbuf_setup(void)
static struct sysctllog *mbuf_sysctllog;
static struct mbuf *m_copym0(struct mbuf *, int, int, int, bool);
-static struct mbuf *m_split0(struct mbuf *, int, int, int);
+static struct mbuf *m_split0(struct mbuf *, int, int, bool);
static int m_copyback0(struct mbuf **, int, int, const void *, int, int);
/* flags for m_copyback0 */
@@ -772,12 +772,8 @@ m_copym0(struct mbuf *m, int off0, int l
MCLADDREFERENCE(m, n);
} else {
/*
- * we are unsure about the way m was allocated.
- * copy into multiple MCLBYTES cluster mbufs.
- *
- * recompute m_len, it is no longer valid if MCLGET()
- * fails to allocate a cluster. Then we try to split
- * the source into normal sized mbufs.
+ * We don't care if MCLGET fails. n->m_len is
+ * recomputed and handles that.
*/
MCLGET(n, wait);
n->m_len = 0;
@@ -819,7 +815,7 @@ nospace:
/*
* Copy an entire packet, including header (which must be present).
- * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
+ * An optimization of the common case 'm_copym(m, 0, M_COPYALL, how)'.
*/
struct mbuf *
m_copypacket(struct mbuf *m, int how)
@@ -862,6 +858,7 @@ m_copypacket(struct mbuf *m, int how)
m = m->m_next;
}
return top;
+
nospace:
m_freem(top);
MCFail++;
@@ -959,9 +956,8 @@ m_adj(struct mbuf *mp, int req_len)
len = 0;
}
}
- m = mp;
if (mp->m_flags & M_PKTHDR)
- m->m_pkthdr.len -= (req_len - len);
+ mp->m_pkthdr.len -= (req_len - len);
} else {
/*
* Trim from tail. Scan the mbuf chain,
@@ -974,7 +970,7 @@ m_adj(struct mbuf *mp, int req_len)
count = 0;
for (;;) {
count += m->m_len;
- if (m->m_next == (struct mbuf *)0)
+ if (m->m_next == NULL)
break;
m = m->m_next;
}
@@ -984,9 +980,11 @@ m_adj(struct mbuf *mp, int req_len)
mp->m_pkthdr.len -= len;
return;
}
+
count -= len;
if (count < 0)
count = 0;
+
/*
* Correct length for chain is "count".
* Find the mbuf with last data, adjust its length,
@@ -1002,9 +1000,10 @@ m_adj(struct mbuf *mp, int req_len)
}
count -= m->m_len;
}
- if (m)
+ if (m) {
while (m->m_next)
(m = m->m_next)->m_len = 0;
+ }
}
}
@@ -1149,11 +1148,11 @@ struct mbuf *
m_split(struct mbuf *m0, int len0, int wait)
{
- return m_split0(m0, len0, wait, 1);
+ return m_split0(m0, len0, wait, true);
}
static struct mbuf *
-m_split0(struct mbuf *m0, int len0, int wait, int copyhdr)
+m_split0(struct mbuf *m0, int len0, int wait, bool copyhdr)
{
struct mbuf *m, *n;
unsigned len = len0, remain, len_save;
@@ -1161,44 +1160,50 @@ m_split0(struct mbuf *m0, int len0, int
KASSERT(len0 != M_COPYALL);
for (m = m0; m && len > m->m_len; m = m->m_next)
len -= m->m_len;
- if (m == 0)
- return (NULL);
+ if (m == NULL)
+ return NULL;
+
remain = m->m_len - len;
if (copyhdr && (m0->m_flags & M_PKTHDR)) {
n = m_gethdr(wait, m0->m_type);
if (n == NULL)
return NULL;
+
MCLAIM(n, m0->m_owner);
m_copy_rcvif(n, m0);
n->m_pkthdr.len = m0->m_pkthdr.len - len0;
len_save = m0->m_pkthdr.len;
m0->m_pkthdr.len = len0;
+
if (m->m_flags & M_EXT)
goto extpacket;
+
if (remain > MHLEN) {
/* m can't be the lead packet */
MH_ALIGN(n, 0);
n->m_len = 0;
n->m_next = m_split(m, len, wait);
- if (n->m_next == 0) {
- (void) m_free(n);
+ if (n->m_next == NULL) {
+ (void)m_free(n);
m0->m_pkthdr.len = len_save;
- return (NULL);
- } else
- return (n);
- } else
+ return NULL;
+ }
+ return n;
+ } else {
MH_ALIGN(n, remain);
+ }
} else if (remain == 0) {
n = m->m_next;
- m->m_next = 0;
- return (n);
+ m->m_next = NULL;
+ return n;
} else {
n = m_get(wait, m->m_type);
- if (n == 0)
- return (NULL);
+ if (n == NULL)
+ return NULL;
MCLAIM(n, m->m_owner);
M_ALIGN(n, remain);
}
+
extpacket:
if (m->m_flags & M_EXT) {
n->m_data = m->m_data + len;
@@ -1206,12 +1211,14 @@ extpacket:
} else {
memcpy(mtod(n, void *), mtod(m, char *) + len, remain);
}
+
n->m_len = remain;
m->m_len = len;
n->m_next = m->m_next;
- m->m_next = 0;
- return (n);
+ m->m_next = NULL;
+ return n;
}
+
/*
* Routine to copy from device local memory into mbufs.
*/
@@ -1220,10 +1227,9 @@ m_devget(char *buf, int totlen, int off0
void (*copy)(const void *from, void *to, size_t len))
{
struct mbuf *m;
- struct mbuf *top = 0, **mp = ⊤
+ struct mbuf *top = NULL, **mp = ⊤
int off = off0, len;
- char *cp;
- char *epkt;
+ char *cp, *epkt;
cp = buf;
epkt = cp + totlen;
@@ -1235,6 +1241,7 @@ m_devget(char *buf, int totlen, int off0
cp += off + 2 * sizeof(uint16_t);
totlen -= 2 * sizeof(uint16_t);
}
+
m = m_gethdr(M_DONTWAIT, MT_DATA);
if (m == NULL)
return NULL;
@@ -1245,19 +1252,21 @@ m_devget(char *buf, int totlen, int off0
while (totlen > 0) {
if (top) {
m = m_get(M_DONTWAIT, MT_DATA);
- if (m == 0) {
+ if (m == NULL) {
m_freem(top);
- return (NULL);
+ return NULL;
}
m->m_len = MLEN;
}
+
len = min(totlen, epkt - cp);
+
if (len >= MINCLSIZE) {
MCLGET(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
m_freem(top);
- return (NULL);
+ return NULL;
}
m->m_len = len = min(len, MCLBYTES);
} else {
@@ -1271,10 +1280,12 @@ m_devget(char *buf, int totlen, int off0
} else
len = m->m_len;
}
+
if (copy)
copy(cp, mtod(m, void *), (size_t)len);
else
memcpy(mtod(m, void *), cp, (size_t)len);
+
cp += len;
*mp = m;
mp = &m->m_next;
@@ -1282,7 +1293,8 @@ m_devget(char *buf, int totlen, int off0
if (cp == epkt)
cp = buf;
}
- return (top);
+
+ return top;
}
/*
@@ -1296,21 +1308,21 @@ m_copyback(struct mbuf *m0, int off, int
#if defined(DEBUG)
struct mbuf *origm = m0;
int error;
-#endif /* defined(DEBUG) */
+#endif
if (m0 == NULL)
return;
#if defined(DEBUG)
error =
-#endif /* defined(DEBUG) */
+#endif
m_copyback0(&m0, off, len, cp,
M_COPYBACK0_COPYBACK|M_COPYBACK0_EXTEND, M_DONTWAIT);
#if defined(DEBUG)
if (error != 0 || (m0 != NULL && origm != m0))
panic("m_copyback");
-#endif /* defined(DEBUG) */
+#endif
}
struct mbuf *
@@ -1344,7 +1356,7 @@ m_makewritable(struct mbuf **mp, int off
int error;
#if defined(DEBUG)
int origlen = m_length(*mp);
-#endif /* defined(DEBUG) */
+#endif
error = m_copyback0(mp, off, len, NULL,
M_COPYBACK0_PRESERVE|M_COPYBACK0_COW, how);
@@ -1360,7 +1372,7 @@ m_makewritable(struct mbuf **mp, int off
panic("m_makewritable: length changed");
if (((*mp)->m_flags & M_PKTHDR) != 0 && reslen != (*mp)->m_pkthdr.len)
panic("m_makewritable: inconsist");
-#endif /* defined(DEBUG) */
+#endif
return 0;
}
@@ -1376,10 +1388,7 @@ m_defrag(struct mbuf *mold, int flags)
struct mbuf *m0, *mn, *n;
size_t sz = mold->m_pkthdr.len;
-#ifdef DIAGNOSTIC
- if ((mold->m_flags & M_PKTHDR) == 0)
- panic("m_defrag: not a mbuf chain header");
-#endif
+ KASSERT((mold->m_flags & M_PKTHDR) != 0);
m0 = m_gethdr(flags, MT_DATA);
if (m0 == NULL)
@@ -1518,7 +1527,7 @@ extend:
* a mbuf, split it first.
*/
if (off > 0) {
- n = m_split0(m, off, how, 0);
+ n = m_split0(m, off, how, false);
if (n == NULL)
goto enobufs;
m->m_next = n;
@@ -1651,14 +1660,14 @@ m_apply(struct mbuf *m, int off, int len
rval = (*f)(arg, mtod(m, char *) + off, count);
if (rval)
- return (rval);
+ return rval;
len -= count;
off = 0;
m = m->m_next;
}
- return (0);
+ return 0;
}
/*
@@ -1672,23 +1681,24 @@ m_getptr(struct mbuf *m, int loc, int *o
/* Normal end of search */
if (m->m_len > loc) {
*off = loc;
- return (m);
- } else {
- loc -= m->m_len;
+ return m;
+ }
- if (m->m_next == NULL) {
- if (loc == 0) {
- /* Point at the end of valid data */
- *off = m->m_len;
- return (m);
- } else
- return (NULL);
- } else
- m = m->m_next;
+ loc -= m->m_len;
+
+ if (m->m_next == NULL) {
+ if (loc == 0) {
+ /* Point at the end of valid data */
+ *off = m->m_len;
+ return m;
+ }
+ return NULL;
+ } else {
+ m = m->m_next;
}
}
- return (NULL);
+ return NULL;
}
/*
@@ -1700,7 +1710,7 @@ m_getptr(struct mbuf *m, int loc, int *o
void
m_ext_free(struct mbuf *m)
{
- bool embedded = MEXT_ISEMBEDDED(m);
+ const bool embedded = MEXT_ISEMBEDDED(m);
bool dofree = true;
u_int refcnt;
@@ -1719,6 +1729,7 @@ m_ext_free(struct mbuf *m)
} else {
refcnt = atomic_dec_uint_nv(&m->m_ext.ext_refcnt);
}
+
if (refcnt > 0) {
if (embedded) {
/*
@@ -1752,6 +1763,7 @@ m_ext_free(struct mbuf *m)
free(m->m_ext.ext_buf, m->m_ext.ext_type);
}
}
+
if (dofree) {
m->m_type = MT_FREE;
m->m_data = NULL;
