The branch stable/13 has been updated by jhb: URL: https://cgit.FreeBSD.org/src/commit/?id=8efc88d0d6a044e5928bec64447fcbc24b8f01b2
commit 8efc88d0d6a044e5928bec64447fcbc24b8f01b2 Author: John Baldwin <[email protected]> AuthorDate: 2021-05-25 23:59:18 +0000 Commit: John Baldwin <[email protected]> CommitDate: 2021-10-21 15:51:25 +0000 Extend m_copyback() to support unmapped mbufs. Reviewed by: gallatin, markj Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D30133 (cherry picked from commit 3f9dac85cc8f2963026fdc2d5477acb607176a89) --- sys/kern/uipc_mbuf.c | 30 ++++++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-) diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c index 8b5b83337d56..b141cb5f43a2 100644 --- a/sys/kern/uipc_mbuf.c +++ b/sys/kern/uipc_mbuf.c @@ -1139,6 +1139,29 @@ m_devget(char *buf, int totlen, int off, struct ifnet *ifp, return (top); } +static void +m_copytounmapped(const struct mbuf *m, int off, int len, c_caddr_t cp) +{ + struct iovec iov; + struct uio uio; + int error; + + KASSERT(off >= 0, ("m_copytounmapped: negative off %d", off)); + KASSERT(len >= 0, ("m_copytounmapped: negative len %d", len)); + KASSERT(off < m->m_len, ("m_copytounmapped: len exceeds mbuf length")); + iov.iov_base = __DECONST(caddr_t, cp); + iov.iov_len = len; + uio.uio_resid = len; + uio.uio_iov = &iov; + uio.uio_segflg = UIO_SYSSPACE; + uio.uio_iovcnt = 1; + uio.uio_offset = 0; + uio.uio_rw = UIO_WRITE; + error = m_unmappedtouio(m, off, &uio, len); + KASSERT(error == 0, ("m_unmappedtouio failed: off %d, len %d", off, + len)); +} + /* * Copy data from a buffer back into the indicated mbuf chain, * starting "off" bytes from the beginning, extending the mbuf @@ -1172,7 +1195,10 @@ m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp) M_TRAILINGSPACE(m)); } mlen = min (m->m_len - off, len); - bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen); + if ((m->m_flags & M_EXTPG) != 0) + m_copytounmapped(m, off, mlen, cp); + else + bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen); cp += mlen; len -= mlen; mlen += off; @@ -1870,7 +1896,7 @@ m_uiotombuf(struct uio *uio, int how, int len, int align, int flags) } /* - * Copy data from an unmapped mbuf into a uio limited by len if set. + * Copy data to/from an unmapped mbuf into a uio limited by len if set. */ int m_unmappedtouio(const struct mbuf *m, int m_off, struct uio *uio, int len)
