Break out functionality in sosend() responsible for building mbuf
chains and copying in mbufs from the body of the send logic, creating a new function sosend_copyin(). This changes makes sosend() almost readable, and will allow the same logic to be used by tailored socket send routines. MFC after: 1 month Reviewed by: andre, glebius
This commit is contained in:
Robert Watson
parent
91978388e2
commit
a725629cf8
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=152894
@ -575,7 +575,134 @@ sodisconnect(so)
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return (error);
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}
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/*
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* sosend_copyin() accepts a uio and prepares an mbuf chain holding part or
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* all of the data referenced by the uio. If desired, it uses zero-copy.
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* *space will be updated to reflect data copied in.
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*
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* NB: If atomic I/O is requested, the caller must already have checked that
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* space can hold resid bytes.
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*
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* NB: In the event of an error, the caller may need to free the partial
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* chain pointed to by *mpp. The contents of both *uio and *space may be
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* modified even in the case of an error.
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*/
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static int
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sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
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int flags)
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{
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struct mbuf *m, **mp, *top;
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long len, resid;
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int error;
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#ifdef ZERO_COPY_SOCKETS
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int cow_send;
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#endif
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*retmp = top = NULL;
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mp = ⊤
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len = 0;
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resid = uio->uio_resid;
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error = 0;
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do {
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#ifdef ZERO_COPY_SOCKETS
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cow_send = 0;
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#endif /* ZERO_COPY_SOCKETS */
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if (resid >= MINCLSIZE) {
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#ifdef ZERO_COPY_SOCKETS
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if (top == NULL) {
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MGETHDR(m, M_TRYWAIT, MT_DATA);
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if (m == NULL) {
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error = ENOBUFS;
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goto out;
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}
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m->m_pkthdr.len = 0;
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m->m_pkthdr.rcvif = NULL;
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} else {
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MGET(m, M_TRYWAIT, MT_DATA);
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if (m == NULL) {
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error = ENOBUFS;
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goto out;
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}
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}
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if (so_zero_copy_send &&
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resid>=PAGE_SIZE &&
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*space>=PAGE_SIZE &&
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uio->uio_iov->iov_len>=PAGE_SIZE) {
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so_zerocp_stats.size_ok++;
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so_zerocp_stats.align_ok++;
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cow_send = socow_setup(m, uio);
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len = cow_send;
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}
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if (!cow_send) {
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MCLGET(m, M_TRYWAIT);
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if ((m->m_flags & M_EXT) == 0) {
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m_free(m);
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m = NULL;
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} else {
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len = min(min(MCLBYTES, resid),
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*space);
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}
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}
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#else /* ZERO_COPY_SOCKETS */
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if (top == NULL) {
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m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR);
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m->m_pkthdr.len = 0;
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m->m_pkthdr.rcvif = NULL;
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} else
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m = m_getcl(M_TRYWAIT, MT_DATA, 0);
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len = min(min(MCLBYTES, resid), *space);
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#endif /* ZERO_COPY_SOCKETS */
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} else {
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if (top == NULL) {
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m = m_gethdr(M_TRYWAIT, MT_DATA);
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m->m_pkthdr.len = 0;
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m->m_pkthdr.rcvif = NULL;
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len = min(min(MHLEN, resid), *space);
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/*
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* For datagram protocols, leave room
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* for protocol headers in first mbuf.
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*/
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if (atomic && m && len < MHLEN)
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MH_ALIGN(m, len);
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} else {
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m = m_get(M_TRYWAIT, MT_DATA);
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len = min(min(MLEN, resid), *space);
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}
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}
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if (m == NULL) {
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error = ENOBUFS;
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goto out;
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}
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*space -= len;
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#ifdef ZERO_COPY_SOCKETS
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if (cow_send)
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error = 0;
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else
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#endif /* ZERO_COPY_SOCKETS */
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error = uiomove(mtod(m, void *), (int)len, uio);
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resid = uio->uio_resid;
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m->m_len = len;
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*mp = m;
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top->m_pkthdr.len += len;
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if (error)
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goto out;
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mp = &m->m_next;
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if (resid <= 0) {
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if (flags & MSG_EOR)
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top->m_flags |= M_EOR;
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break;
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}
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} while (*space > 0 && atomic);
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out:
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*retmp = top;
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return (error);
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}
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#define SBLOCKWAIT(f) (((f) & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK)
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#define snderr(errno) { error = (errno); goto out; }
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/*
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* Send on a socket.
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* If send must go all at once and message is larger than
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@ -619,14 +746,9 @@ sosend(so, addr, uio, top, control, flags, td)
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int flags;
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struct thread *td;
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{
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struct mbuf **mp;
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struct mbuf *m;
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long space, len = 0, resid;
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long space, resid;
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int clen = 0, error, dontroute;
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int atomic = sosendallatonce(so) || top;
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#ifdef ZERO_COPY_SOCKETS
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int cow_send;
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#endif /* ZERO_COPY_SOCKETS */
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if (uio != NULL)
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resid = uio->uio_resid;
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@ -654,7 +776,6 @@ sosend(so, addr, uio, top, control, flags, td)
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td->td_proc->p_stats->p_ru.ru_msgsnd++;
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if (control != NULL)
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clen = control->m_len;
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#define snderr(errno) { error = (errno); goto release; }
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SOCKBUF_LOCK(&so->so_snd);
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restart:
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@ -704,112 +825,21 @@ sosend(so, addr, uio, top, control, flags, td)
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goto restart;
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}
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SOCKBUF_UNLOCK(&so->so_snd);
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mp = ⊤
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space -= clen;
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do {
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if (uio == NULL) {
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/*
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* Data is prepackaged in "top".
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*/
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resid = 0;
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if (flags & MSG_EOR)
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top->m_flags |= M_EOR;
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} else do {
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#ifdef ZERO_COPY_SOCKETS
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cow_send = 0;
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#endif /* ZERO_COPY_SOCKETS */
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if (resid >= MINCLSIZE) {
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#ifdef ZERO_COPY_SOCKETS
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if (top == NULL) {
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MGETHDR(m, M_TRYWAIT, MT_DATA);
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if (m == NULL) {
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error = ENOBUFS;
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} else {
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error = sosend_copyin(uio, &top, atomic,
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&space, flags);
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if (error != 0) {
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SOCKBUF_LOCK(&so->so_snd);
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goto release;
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}
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m->m_pkthdr.len = 0;
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m->m_pkthdr.rcvif = NULL;
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} else {
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MGET(m, M_TRYWAIT, MT_DATA);
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if (m == NULL) {
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error = ENOBUFS;
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SOCKBUF_LOCK(&so->so_snd);
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goto release;
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}
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}
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if (so_zero_copy_send &&
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resid>=PAGE_SIZE &&
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space>=PAGE_SIZE &&
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uio->uio_iov->iov_len>=PAGE_SIZE) {
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so_zerocp_stats.size_ok++;
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so_zerocp_stats.align_ok++;
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cow_send = socow_setup(m, uio);
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len = cow_send;
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}
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if (!cow_send) {
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MCLGET(m, M_TRYWAIT);
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if ((m->m_flags & M_EXT) == 0) {
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m_free(m);
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m = NULL;
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} else {
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len = min(min(MCLBYTES, resid), space);
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}
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}
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#else /* ZERO_COPY_SOCKETS */
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if (top == NULL) {
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m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR);
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m->m_pkthdr.len = 0;
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m->m_pkthdr.rcvif = NULL;
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} else
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m = m_getcl(M_TRYWAIT, MT_DATA, 0);
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len = min(min(MCLBYTES, resid), space);
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#endif /* ZERO_COPY_SOCKETS */
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} else {
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if (top == NULL) {
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m = m_gethdr(M_TRYWAIT, MT_DATA);
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m->m_pkthdr.len = 0;
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m->m_pkthdr.rcvif = NULL;
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len = min(min(MHLEN, resid), space);
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/*
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* For datagram protocols, leave room
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* for protocol headers in first mbuf.
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*/
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if (atomic && m && len < MHLEN)
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MH_ALIGN(m, len);
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} else {
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m = m_get(M_TRYWAIT, MT_DATA);
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len = min(min(MLEN, resid), space);
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}
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}
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if (m == NULL) {
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error = ENOBUFS;
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SOCKBUF_LOCK(&so->so_snd);
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goto release;
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}
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space -= len;
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#ifdef ZERO_COPY_SOCKETS
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if (cow_send)
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error = 0;
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else
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#endif /* ZERO_COPY_SOCKETS */
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error = uiomove(mtod(m, void *), (int)len, uio);
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resid = uio->uio_resid;
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m->m_len = len;
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*mp = m;
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top->m_pkthdr.len += len;
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if (error) {
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SOCKBUF_LOCK(&so->so_snd);
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goto release;
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}
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mp = &m->m_next;
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if (resid <= 0) {
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if (flags & MSG_EOR)
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top->m_flags |= M_EOR;
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break;
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}
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} while (space > 0 && atomic);
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if (dontroute) {
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SOCK_LOCK(so);
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so->so_options |= SO_DONTROUTE;
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@ -846,7 +876,6 @@ sosend(so, addr, uio, top, control, flags, td)
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clen = 0;
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control = NULL;
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top = NULL;
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mp = ⊤
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if (error) {
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SOCKBUF_LOCK(&so->so_snd);
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goto release;
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