diff options
| -rw-r--r-- | sys/kern/uipc_mbuf.c | 109 |
1 files changed, 65 insertions, 44 deletions
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c index 1ae467444a7..b0fd510f330 100644 --- a/sys/kern/uipc_mbuf.c +++ b/sys/kern/uipc_mbuf.c @@ -1,4 +1,4 @@ -/* $OpenBSD: uipc_mbuf.c,v 1.265 2019/01/09 16:37:27 visa Exp $ */ +/* $OpenBSD: uipc_mbuf.c,v 1.266 2019/02/01 10:43:43 dlg Exp $ */ /* $NetBSD: uipc_mbuf.c,v 1.15.4.1 1996/06/13 17:11:44 cgd Exp $ */ /* @@ -908,84 +908,105 @@ m_adj(struct mbuf *mp, int req_len) * mbuf chain on success, frees it and returns null on failure. */ struct mbuf * -m_pullup(struct mbuf *n, int len) +m_pullup(struct mbuf *m0, int len) { struct mbuf *m; unsigned int adj; caddr_t head, tail; unsigned int space; - /* if n is already contig then don't do any work */ - if (len <= n->m_len) - return (n); + /* if len is already contig in m0, then don't do any work */ + if (len <= m0->m_len) + return (m0); + + /* look for some data */ + m = m0->m_next; + if (m == NULL) + goto freem0; + + head = M_DATABUF(m0); + if (m0->m_len == 0) { + m0->m_data = head; - adj = (unsigned long)n->m_data & ALIGNBYTES; - head = (caddr_t)ALIGN(mtod(n, caddr_t) - m_leadingspace(n)) + adj; - tail = mtod(n, caddr_t) + n->m_len + m_trailingspace(n); + while (m->m_len == 0) { + m = m_free(m); + if (m == NULL) + goto freem0; + } + + adj = mtod(m, unsigned long) & ALIGNBYTES; + } else + adj = mtod(m0, unsigned long) & ALIGNBYTES; - if (head < tail && len <= tail - head) { + tail = head + M_SIZE(m0); + head += adj; + + if (len <= tail - head) { /* there's enough space in the first mbuf */ - if (len > tail - mtod(n, caddr_t)) { + if (len > tail - mtod(m0, caddr_t)) { /* need to memmove to make space at the end */ - memmove(head, mtod(n, caddr_t), n->m_len); - n->m_data = head; + memmove(head, mtod(m0, caddr_t), m0->m_len); + m0->m_data = head; } - len -= n->m_len; - m = n; - n = m->m_next; + len -= m0->m_len; } else { - /* the first mbuf is too small so prepend one with space */ + /* the first mbuf is too small so make a new one */ space = adj + len; if (space > MAXMCLBYTES) goto bad; - MGET(m, M_DONTWAIT, n->m_type); - if (m == NULL) + m0->m_next = m; + m = m0; + + MGET(m0, M_DONTWAIT, m->m_type); + if (m0 == NULL) goto bad; + if (space > MHLEN) { - MCLGETI(m, M_DONTWAIT, NULL, space); - if ((m->m_flags & M_EXT) == 0) { - m_free(m); + MCLGETI(m0, M_DONTWAIT, NULL, space); + if ((m0->m_flags & M_EXT) == 0) goto bad; - } } - if (n->m_flags & M_PKTHDR) - M_MOVE_PKTHDR(m, n); + if (m->m_flags & M_PKTHDR) + M_MOVE_PKTHDR(m0, m); - m->m_len = 0; - m->m_data += adj; + m0->m_len = 0; + m0->m_data += adj; } - KASSERT(m_trailingspace(m) >= len); + KDASSERT(m_trailingspace(m0) >= len); - do { - if (n == NULL) { - (void)m_free(m); - goto bad; - } - - space = min(len, n->m_len); - memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t), space); + for (;;) { + space = min(len, m->m_len); + memcpy(mtod(m0, caddr_t) + m0->m_len, mtod(m, caddr_t), space); len -= space; - m->m_len += space; - n->m_len -= space; + m0->m_len += space; + m->m_len -= space; - if (n->m_len > 0) - n->m_data += space; + if (m->m_len > 0) + m->m_data += space; else - n = m_free(n); - } while (len > 0); + m = m_free(m); - m->m_next = n; + if (len == 0) + break; - return (m); + if (m == NULL) + goto bad; + } + + m0->m_next = m; /* link the chain back up */ + + return (m0); bad: - m_freem(n); + m_freem(m); +freem0: + m_free(m0); return (NULL); } |