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Improve m_cat() by being able to also merge contents from M_EXT

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mbuf's by doing proper testing with M_WRITABLE().

In m_collapse() replace an incomplete manual check for M_RDONLY
with the M_WRITABLE() macro that also tests for shared buffers
and other cases that make a particular mbuf immutable.

MFC after:	2 weeks
This commit is contained in:
Andre Oppermann 2012-10-28 18:38:51 +00:00
parent 4faaea5505
commit 14d7c5b11c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=242256
1 changed files with 3 additions and 3 deletions
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6
sys/kern/uipc_mbuf.c
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@ -911,8 +911,8 @@ m_cat(struct mbuf *m, struct mbuf *n)
while (m->m_next)
m = m->m_next;
while (n) {
if (m->m_flags & M_EXT ||
m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
if (!M_WRITABLE(m) ||
M_TRAILINGSPACE(m) < n->m_len) {
/* just join the two chains */
m->m_next = n;
return;
@ -1584,7 +1584,7 @@ m_collapse(struct mbuf *m0, int how, int maxfrags)
n = m->m_next;
if (n == NULL)
break;
if ((m->m_flags & M_RDONLY) == 0 &&
if (M_WRITABLE(m) &&
n->m_len < M_TRAILINGSPACE(m)) {
bcopy(mtod(n, void *), mtod(m, char *) + m->m_len,
n->m_len);