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Break out functionality in sosend() responsible for building mbuf

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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 2005-11-28 18:09:03 +00:00
parent 91978388e2
commit a725629cf8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=152894
1 changed files with 171 additions and 142 deletions
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313
sys/kern/uipc_socket.c
View File

@ -575,7 +575,134 @@ sodisconnect(so)
return (error);
}
/*
* sosend_copyin() accepts a uio and prepares an mbuf chain holding part or
* all of the data referenced by the uio. If desired, it uses zero-copy.
* *space will be updated to reflect data copied in.
*
* NB: If atomic I/O is requested, the caller must already have checked that
* space can hold resid bytes.
*
* NB: In the event of an error, the caller may need to free the partial
* chain pointed to by *mpp. The contents of both *uio and *space may be
* modified even in the case of an error.
*/
static int
sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
int flags)
{
struct mbuf *m, **mp, *top;
long len, resid;
int error;
#ifdef ZERO_COPY_SOCKETS
int cow_send;
#endif
*retmp = top = NULL;
mp = ⊤
len = 0;
resid = uio->uio_resid;
error = 0;
do {
#ifdef ZERO_COPY_SOCKETS
cow_send = 0;
#endif /* ZERO_COPY_SOCKETS */
if (resid >= MINCLSIZE) {
#ifdef ZERO_COPY_SOCKETS
if (top == NULL) {
MGETHDR(m, M_TRYWAIT, MT_DATA);
if (m == NULL) {
error = ENOBUFS;
goto out;
}
m->m_pkthdr.len = 0;
m->m_pkthdr.rcvif = NULL;
} else {
MGET(m, M_TRYWAIT, MT_DATA);
if (m == NULL) {
error = ENOBUFS;
goto out;
}
}
if (so_zero_copy_send &&
resid>=PAGE_SIZE &&
*space>=PAGE_SIZE &&
uio->uio_iov->iov_len>=PAGE_SIZE) {
so_zerocp_stats.size_ok++;
so_zerocp_stats.align_ok++;
cow_send = socow_setup(m, uio);
len = cow_send;
}
if (!cow_send) {
MCLGET(m, M_TRYWAIT);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
m = NULL;
} else {
len = min(min(MCLBYTES, resid),
*space);
}
}
#else /* ZERO_COPY_SOCKETS */
if (top == NULL) {
m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR);
m->m_pkthdr.len = 0;
m->m_pkthdr.rcvif = NULL;
} else
m = m_getcl(M_TRYWAIT, MT_DATA, 0);
len = min(min(MCLBYTES, resid), *space);
#endif /* ZERO_COPY_SOCKETS */
} else {
if (top == NULL) {
m = m_gethdr(M_TRYWAIT, MT_DATA);
m->m_pkthdr.len = 0;
m->m_pkthdr.rcvif = NULL;
len = min(min(MHLEN, resid), *space);
/*
* For datagram protocols, leave room
* for protocol headers in first mbuf.
*/
if (atomic && m && len < MHLEN)
MH_ALIGN(m, len);
} else {
m = m_get(M_TRYWAIT, MT_DATA);
len = min(min(MLEN, resid), *space);
}
}
if (m == NULL) {
error = ENOBUFS;
goto out;
}
*space -= len;
#ifdef ZERO_COPY_SOCKETS
if (cow_send)
error = 0;
else
#endif /* ZERO_COPY_SOCKETS */
error = uiomove(mtod(m, void *), (int)len, uio);
resid = uio->uio_resid;
m->m_len = len;
*mp = m;
top->m_pkthdr.len += len;
if (error)
goto out;
mp = &m->m_next;
if (resid <= 0) {
if (flags & MSG_EOR)
top->m_flags |= M_EOR;
break;
}
} while (*space > 0 && atomic);
out:
*retmp = top;
return (error);
}
#define SBLOCKWAIT(f) (((f) & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK)
#define snderr(errno) { error = (errno); goto out; }
/*
* Send on a socket.
* If send must go all at once and message is larger than
@ -619,14 +746,9 @@ sosend(so, addr, uio, top, control, flags, td)
int flags;
struct thread *td;
{
struct mbuf **mp;
struct mbuf *m;
long space, len = 0, resid;
long space, resid;
int clen = 0, error, dontroute;
int atomic = sosendallatonce(so) || top;
#ifdef ZERO_COPY_SOCKETS
int cow_send;
#endif /* ZERO_COPY_SOCKETS */
if (uio != NULL)
resid = uio->uio_resid;
@ -654,7 +776,6 @@ sosend(so, addr, uio, top, control, flags, td)
td->td_proc->p_stats->p_ru.ru_msgsnd++;
if (control != NULL)
clen = control->m_len;
#define snderr(errno) { error = (errno); goto release; }
SOCKBUF_LOCK(&so->so_snd);
restart:
@ -704,153 +825,61 @@ sosend(so, addr, uio, top, control, flags, td)
goto restart;
}
SOCKBUF_UNLOCK(&so->so_snd);
mp = &top;
space -= clen;
do {
if (uio == NULL) {
/*
* Data is prepackaged in "top".
*/
resid = 0;
if (flags & MSG_EOR)
top->m_flags |= M_EOR;
} else do {
#ifdef ZERO_COPY_SOCKETS
cow_send = 0;
#endif /* ZERO_COPY_SOCKETS */
if (resid >= MINCLSIZE) {
#ifdef ZERO_COPY_SOCKETS
if (top == NULL) {
MGETHDR(m, M_TRYWAIT, MT_DATA);
if (m == NULL) {
error = ENOBUFS;
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
m->m_pkthdr.len = 0;
m->m_pkthdr.rcvif = NULL;
} else {
MGET(m, M_TRYWAIT, MT_DATA);
if (m == NULL) {
error = ENOBUFS;
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
}
if (so_zero_copy_send &&
resid>=PAGE_SIZE &&
space>=PAGE_SIZE &&
uio->uio_iov->iov_len>=PAGE_SIZE) {
so_zerocp_stats.size_ok++;
so_zerocp_stats.align_ok++;
cow_send = socow_setup(m, uio);
len = cow_send;
}
if (!cow_send) {
MCLGET(m, M_TRYWAIT);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
m = NULL;
} else {
len = min(min(MCLBYTES, resid), space);
}
}
#else /* ZERO_COPY_SOCKETS */
if (top == NULL) {
m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR);
m->m_pkthdr.len = 0;
m->m_pkthdr.rcvif = NULL;
} else
m = m_getcl(M_TRYWAIT, MT_DATA, 0);
len = min(min(MCLBYTES, resid), space);
#endif /* ZERO_COPY_SOCKETS */
} else {
if (top == NULL) {
m = m_gethdr(M_TRYWAIT, MT_DATA);
m->m_pkthdr.len = 0;
m->m_pkthdr.rcvif = NULL;
len = min(min(MHLEN, resid), space);
/*
* For datagram protocols, leave room
* for protocol headers in first mbuf.
*/
if (atomic && m && len < MHLEN)
MH_ALIGN(m, len);
} else {
m = m_get(M_TRYWAIT, MT_DATA);
len = min(min(MLEN, resid), space);
}
}
if (m == NULL) {
error = ENOBUFS;
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
space -= len;
#ifdef ZERO_COPY_SOCKETS
if (cow_send)
error = 0;
else
#endif /* ZERO_COPY_SOCKETS */
error = uiomove(mtod(m, void *), (int)len, uio);
resid = uio->uio_resid;
m->m_len = len;
*mp = m;
top->m_pkthdr.len += len;
if (error) {
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
mp = &m->m_next;
if (resid <= 0) {
if (uio == NULL) {
resid = 0;
if (flags & MSG_EOR)
top->m_flags |= M_EOR;
break;
} else {
error = sosend_copyin(uio, &top, atomic,
&space, flags);
if (error != 0) {
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
resid = uio->uio_resid;
}
} while (space > 0 && atomic);
if (dontroute) {
SOCK_LOCK(so);
so->so_options |= SO_DONTROUTE;
SOCK_UNLOCK(so);
}
/*
* XXX all the SBS_CANTSENDMORE checks previously
* done could be out of date. We could have recieved
* a reset packet in an interrupt or maybe we slept
* while doing page faults in uiomove() etc. We could
* probably recheck again inside the locking protection
* here, but there are probably other places that this
* also happens. We must rethink this.
*/
error = (*so->so_proto->pr_usrreqs->pru_send)(so,
(flags & MSG_OOB) ? PRUS_OOB :
if (dontroute) {
SOCK_LOCK(so);
so->so_options |= SO_DONTROUTE;
SOCK_UNLOCK(so);
}
/*
* XXX all the SBS_CANTSENDMORE checks previously
* done could be out of date. We could have recieved
* a reset packet in an interrupt or maybe we slept
* while doing page faults in uiomove() etc. We could
* probably recheck again inside the locking protection
* here, but there are probably other places that this
* also happens. We must rethink this.
*/
error = (*so->so_proto->pr_usrreqs->pru_send)(so,
(flags & MSG_OOB) ? PRUS_OOB :
/*
* If the user set MSG_EOF, the protocol
* understands this flag and nothing left to
* send then use PRU_SEND_EOF instead of PRU_SEND.
*/
((flags & MSG_EOF) &&
(so->so_proto->pr_flags & PR_IMPLOPCL) &&
(resid <= 0)) ?
((flags & MSG_EOF) &&
(so->so_proto->pr_flags & PR_IMPLOPCL) &&
(resid <= 0)) ?
PRUS_EOF :
/* If there is more to send set PRUS_MORETOCOME */
(resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
top, addr, control, td);
if (dontroute) {
SOCK_LOCK(so);
so->so_options &= ~SO_DONTROUTE;
SOCK_UNLOCK(so);
}
clen = 0;
control = NULL;
top = NULL;
mp = &top;
if (error) {
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
(resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
top, addr, control, td);
if (dontroute) {
SOCK_LOCK(so);
so->so_options &= ~SO_DONTROUTE;
SOCK_UNLOCK(so);
}
clen = 0;
control = NULL;
top = NULL;
if (error) {
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
} while (resid && space > 0);
SOCKBUF_LOCK(&so->so_snd);
} while (resid);