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alistair23-linux/net/atm/svc.c
Linus Torvalds a11e1d432b Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL 
The poll() changes were not well thought out, and completely
unexplained.  They also caused a huge performance regression, because
"->poll()" was no longer a trivial file operation that just called down
to the underlying file operations, but instead did at least two indirect
calls.

Indirect calls are sadly slow now with the Spectre mitigation, but the
performance problem could at least be largely mitigated by changing the
"->get_poll_head()" operation to just have a per-file-descriptor pointer
to the poll head instead.  That gets rid of one of the new indirections.

But that doesn't fix the new complexity that is completely unwarranted
for the regular case.  The (undocumented) reason for the poll() changes
was some alleged AIO poll race fixing, but we don't make the common case
slower and more complex for some uncommon special case, so this all
really needs way more explanations and most likely a fundamental
redesign.

[ This revert is a revert of about 30 different commits, not reverted
  individually because that would just be unnecessarily messy  - Linus ]

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-28 10:40:47 -07:00

692 lines
16 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0
/* net/atm/svc.c - ATM SVC sockets */
/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
#include <linux/string.h>
#include <linux/net.h> /* struct socket, struct proto_ops */
#include <linux/errno.h> /* error codes */
#include <linux/kernel.h> /* printk */
#include <linux/skbuff.h>
#include <linux/wait.h>
#include <linux/sched/signal.h>
#include <linux/fcntl.h> /* O_NONBLOCK */
#include <linux/init.h>
#include <linux/atm.h> /* ATM stuff */
#include <linux/atmsap.h>
#include <linux/atmsvc.h>
#include <linux/atmdev.h>
#include <linux/bitops.h>
#include <net/sock.h> /* for sock_no_* */
#include <linux/uaccess.h>
#include <linux/export.h>
#include "resources.h"
#include "common.h" /* common for PVCs and SVCs */
#include "signaling.h"
#include "addr.h"
static int svc_create(struct net *net, struct socket *sock, int protocol,
int kern);
/*
* Note: since all this is still nicely synchronized with the signaling demon,
* there's no need to protect sleep loops with clis. If signaling is
* moved into the kernel, that would change.
*/
static int svc_shutdown(struct socket *sock, int how)
{
return 0;
}
static void svc_disconnect(struct atm_vcc *vcc)
{
DEFINE_WAIT(wait);
struct sk_buff *skb;
struct sock *sk = sk_atm(vcc);
pr_debug("%p\n", vcc);
if (test_bit(ATM_VF_REGIS, &vcc->flags)) {
sigd_enq(vcc, as_close, NULL, NULL, NULL);
for (;;) {
prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
if (test_bit(ATM_VF_RELEASED, &vcc->flags) || !sigd)
break;
schedule();
}
finish_wait(sk_sleep(sk), &wait);
}
/* beware - socket is still in use by atmsigd until the last
as_indicate has been answered */
while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
atm_return(vcc, skb->truesize);
pr_debug("LISTEN REL\n");
sigd_enq2(NULL, as_reject, vcc, NULL, NULL, &vcc->qos, 0);
dev_kfree_skb(skb);
}
clear_bit(ATM_VF_REGIS, &vcc->flags);
/* ... may retry later */
}
static int svc_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct atm_vcc *vcc;
if (sk) {
vcc = ATM_SD(sock);
pr_debug("%p\n", vcc);
clear_bit(ATM_VF_READY, &vcc->flags);
/*
* VCC pointer is used as a reference,
* so we must not free it (thereby subjecting it to re-use)
* before all pending connections are closed
*/
svc_disconnect(vcc);
vcc_release(sock);
}
return 0;
}
static int svc_bind(struct socket *sock, struct sockaddr *sockaddr,
int sockaddr_len)
{
DEFINE_WAIT(wait);
struct sock *sk = sock->sk;
struct sockaddr_atmsvc *addr;
struct atm_vcc *vcc;
int error;
if (sockaddr_len != sizeof(struct sockaddr_atmsvc))
return -EINVAL;
lock_sock(sk);
if (sock->state == SS_CONNECTED) {
error = -EISCONN;
goto out;
}
if (sock->state != SS_UNCONNECTED) {
error = -EINVAL;
goto out;
}
vcc = ATM_SD(sock);
addr = (struct sockaddr_atmsvc *) sockaddr;
if (addr->sas_family != AF_ATMSVC) {
error = -EAFNOSUPPORT;
goto out;
}
clear_bit(ATM_VF_BOUND, &vcc->flags);
/* failing rebind will kill old binding */
/* @@@ check memory (de)allocation on rebind */
if (!test_bit(ATM_VF_HASQOS, &vcc->flags)) {
error = -EBADFD;
goto out;
}
vcc->local = *addr;
set_bit(ATM_VF_WAITING, &vcc->flags);
sigd_enq(vcc, as_bind, NULL, NULL, &vcc->local);
for (;;) {
prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
break;
schedule();
}
finish_wait(sk_sleep(sk), &wait);
clear_bit(ATM_VF_REGIS, &vcc->flags); /* doesn't count */
if (!sigd) {
error = -EUNATCH;
goto out;
}
if (!sk->sk_err)
set_bit(ATM_VF_BOUND, &vcc->flags);
error = -sk->sk_err;
out:
release_sock(sk);
return error;
}
static int svc_connect(struct socket *sock, struct sockaddr *sockaddr,
int sockaddr_len, int flags)
{
DEFINE_WAIT(wait);
struct sock *sk = sock->sk;
struct sockaddr_atmsvc *addr;
struct atm_vcc *vcc = ATM_SD(sock);
int error;
pr_debug("%p\n", vcc);
lock_sock(sk);
if (sockaddr_len != sizeof(struct sockaddr_atmsvc)) {
error = -EINVAL;
goto out;
}
switch (sock->state) {
default:
error = -EINVAL;
goto out;
case SS_CONNECTED:
error = -EISCONN;
goto out;
case SS_CONNECTING:
if (test_bit(ATM_VF_WAITING, &vcc->flags)) {
error = -EALREADY;
goto out;
}
sock->state = SS_UNCONNECTED;
if (sk->sk_err) {
error = -sk->sk_err;
goto out;
}
break;
case SS_UNCONNECTED:
addr = (struct sockaddr_atmsvc *) sockaddr;
if (addr->sas_family != AF_ATMSVC) {
error = -EAFNOSUPPORT;
goto out;
}
if (!test_bit(ATM_VF_HASQOS, &vcc->flags)) {
error = -EBADFD;
goto out;
}
if (vcc->qos.txtp.traffic_class == ATM_ANYCLASS ||
vcc->qos.rxtp.traffic_class == ATM_ANYCLASS) {
error = -EINVAL;
goto out;
}
if (!vcc->qos.txtp.traffic_class &&
!vcc->qos.rxtp.traffic_class) {
error = -EINVAL;
goto out;
}
vcc->remote = *addr;
set_bit(ATM_VF_WAITING, &vcc->flags);
sigd_enq(vcc, as_connect, NULL, NULL, &vcc->remote);
if (flags & O_NONBLOCK) {
sock->state = SS_CONNECTING;
error = -EINPROGRESS;
goto out;
}
error = 0;
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) {
schedule();
if (!signal_pending(current)) {
prepare_to_wait(sk_sleep(sk), &wait,
TASK_INTERRUPTIBLE);
continue;
}
pr_debug("*ABORT*\n");
/*
* This is tricky:
* Kernel ---close--> Demon
* Kernel <--close--- Demon
* or
* Kernel ---close--> Demon
* Kernel <--error--- Demon
* or
* Kernel ---close--> Demon
* Kernel <--okay---- Demon
* Kernel <--close--- Demon
*/
sigd_enq(vcc, as_close, NULL, NULL, NULL);
while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) {
prepare_to_wait(sk_sleep(sk), &wait,
TASK_INTERRUPTIBLE);
schedule();
}
if (!sk->sk_err)
while (!test_bit(ATM_VF_RELEASED, &vcc->flags) &&
sigd) {
prepare_to_wait(sk_sleep(sk), &wait,
TASK_INTERRUPTIBLE);
schedule();
}
clear_bit(ATM_VF_REGIS, &vcc->flags);
clear_bit(ATM_VF_RELEASED, &vcc->flags);
clear_bit(ATM_VF_CLOSE, &vcc->flags);
/* we're gone now but may connect later */
error = -EINTR;
break;
}
finish_wait(sk_sleep(sk), &wait);
if (error)
goto out;
if (!sigd) {
error = -EUNATCH;
goto out;
}
if (sk->sk_err) {
error = -sk->sk_err;
goto out;
}
}
vcc->qos.txtp.max_pcr = SELECT_TOP_PCR(vcc->qos.txtp);
vcc->qos.txtp.pcr = 0;
vcc->qos.txtp.min_pcr = 0;
error = vcc_connect(sock, vcc->itf, vcc->vpi, vcc->vci);
if (!error)
sock->state = SS_CONNECTED;
else
(void)svc_disconnect(vcc);
out:
release_sock(sk);
return error;
}
static int svc_listen(struct socket *sock, int backlog)
{
DEFINE_WAIT(wait);
struct sock *sk = sock->sk;
struct atm_vcc *vcc = ATM_SD(sock);
int error;
pr_debug("%p\n", vcc);
lock_sock(sk);
/* let server handle listen on unbound sockets */
if (test_bit(ATM_VF_SESSION, &vcc->flags)) {
error = -EINVAL;
goto out;
}
if (test_bit(ATM_VF_LISTEN, &vcc->flags)) {
error = -EADDRINUSE;
goto out;
}
set_bit(ATM_VF_WAITING, &vcc->flags);
sigd_enq(vcc, as_listen, NULL, NULL, &vcc->local);
for (;;) {
prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
break;
schedule();
}
finish_wait(sk_sleep(sk), &wait);
if (!sigd) {
error = -EUNATCH;
goto out;
}
set_bit(ATM_VF_LISTEN, &vcc->flags);
vcc_insert_socket(sk);
sk->sk_max_ack_backlog = backlog > 0 ? backlog : ATM_BACKLOG_DEFAULT;
error = -sk->sk_err;
out:
release_sock(sk);
return error;
}
static int svc_accept(struct socket *sock, struct socket *newsock, int flags,
bool kern)
{
struct sock *sk = sock->sk;
struct sk_buff *skb;
struct atmsvc_msg *msg;
struct atm_vcc *old_vcc = ATM_SD(sock);
struct atm_vcc *new_vcc;
int error;
lock_sock(sk);
error = svc_create(sock_net(sk), newsock, 0, kern);
if (error)
goto out;
new_vcc = ATM_SD(newsock);
pr_debug("%p -> %p\n", old_vcc, new_vcc);
while (1) {
DEFINE_WAIT(wait);
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
while (!(skb = skb_dequeue(&sk->sk_receive_queue)) &&
sigd) {
if (test_bit(ATM_VF_RELEASED, &old_vcc->flags))
break;
if (test_bit(ATM_VF_CLOSE, &old_vcc->flags)) {
error = -sk->sk_err;
break;
}
if (flags & O_NONBLOCK) {
error = -EAGAIN;
break;
}
release_sock(sk);
schedule();
lock_sock(sk);
if (signal_pending(current)) {
error = -ERESTARTSYS;
break;
}
prepare_to_wait(sk_sleep(sk), &wait,
TASK_INTERRUPTIBLE);
}
finish_wait(sk_sleep(sk), &wait);
if (error)
goto out;
if (!skb) {
error = -EUNATCH;
goto out;
}
msg = (struct atmsvc_msg *)skb->data;
new_vcc->qos = msg->qos;
set_bit(ATM_VF_HASQOS, &new_vcc->flags);
new_vcc->remote = msg->svc;
new_vcc->local = msg->local;
new_vcc->sap = msg->sap;
error = vcc_connect(newsock, msg->pvc.sap_addr.itf,
msg->pvc.sap_addr.vpi,
msg->pvc.sap_addr.vci);
dev_kfree_skb(skb);
sk->sk_ack_backlog--;
if (error) {
sigd_enq2(NULL, as_reject, old_vcc, NULL, NULL,
&old_vcc->qos, error);
error = error == -EAGAIN ? -EBUSY : error;
goto out;
}
/* wait should be short, so we ignore the non-blocking flag */
set_bit(ATM_VF_WAITING, &new_vcc->flags);
sigd_enq(new_vcc, as_accept, old_vcc, NULL, NULL);
for (;;) {
prepare_to_wait(sk_sleep(sk_atm(new_vcc)), &wait,
TASK_UNINTERRUPTIBLE);
if (!test_bit(ATM_VF_WAITING, &new_vcc->flags) || !sigd)
break;
release_sock(sk);
schedule();
lock_sock(sk);
}
finish_wait(sk_sleep(sk_atm(new_vcc)), &wait);
if (!sigd) {
error = -EUNATCH;
goto out;
}
if (!sk_atm(new_vcc)->sk_err)
break;
if (sk_atm(new_vcc)->sk_err != ERESTARTSYS) {
error = -sk_atm(new_vcc)->sk_err;
goto out;
}
}
newsock->state = SS_CONNECTED;
out:
release_sock(sk);
return error;
}
static int svc_getname(struct socket *sock, struct sockaddr *sockaddr,
int peer)
{
struct sockaddr_atmsvc *addr;
addr = (struct sockaddr_atmsvc *) sockaddr;
memcpy(addr, peer ? &ATM_SD(sock)->remote : &ATM_SD(sock)->local,
sizeof(struct sockaddr_atmsvc));
return sizeof(struct sockaddr_atmsvc);
}
int svc_change_qos(struct atm_vcc *vcc, struct atm_qos *qos)
{
struct sock *sk = sk_atm(vcc);
DEFINE_WAIT(wait);
set_bit(ATM_VF_WAITING, &vcc->flags);
sigd_enq2(vcc, as_modify, NULL, NULL, &vcc->local, qos, 0);
for (;;) {
prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
if (!test_bit(ATM_VF_WAITING, &vcc->flags) ||
test_bit(ATM_VF_RELEASED, &vcc->flags) || !sigd) {
break;
}
schedule();
}
finish_wait(sk_sleep(sk), &wait);
if (!sigd)
return -EUNATCH;
return -sk->sk_err;
}
static int svc_setsockopt(struct socket *sock, int level, int optname,
char __user *optval, unsigned int optlen)
{
struct sock *sk = sock->sk;
struct atm_vcc *vcc = ATM_SD(sock);
int value, error = 0;
lock_sock(sk);
switch (optname) {
case SO_ATMSAP:
if (level != SOL_ATM || optlen != sizeof(struct atm_sap)) {
error = -EINVAL;
goto out;
}
if (copy_from_user(&vcc->sap, optval, optlen)) {
error = -EFAULT;
goto out;
}
set_bit(ATM_VF_HASSAP, &vcc->flags);
break;
case SO_MULTIPOINT:
if (level != SOL_ATM || optlen != sizeof(int)) {
error = -EINVAL;
goto out;
}
if (get_user(value, (int __user *)optval)) {
error = -EFAULT;
goto out;
}
if (value == 1)
set_bit(ATM_VF_SESSION, &vcc->flags);
else if (value == 0)
clear_bit(ATM_VF_SESSION, &vcc->flags);
else
error = -EINVAL;
break;
default:
error = vcc_setsockopt(sock, level, optname, optval, optlen);
}
out:
release_sock(sk);
return error;
}
static int svc_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen)
{
struct sock *sk = sock->sk;
int error = 0, len;
lock_sock(sk);
if (!__SO_LEVEL_MATCH(optname, level) || optname != SO_ATMSAP) {
error = vcc_getsockopt(sock, level, optname, optval, optlen);
goto out;
}
if (get_user(len, optlen)) {
error = -EFAULT;
goto out;
}
if (len != sizeof(struct atm_sap)) {
error = -EINVAL;
goto out;
}
if (copy_to_user(optval, &ATM_SD(sock)->sap, sizeof(struct atm_sap))) {
error = -EFAULT;
goto out;
}
out:
release_sock(sk);
return error;
}
static int svc_addparty(struct socket *sock, struct sockaddr *sockaddr,
int sockaddr_len, int flags)
{
DEFINE_WAIT(wait);
struct sock *sk = sock->sk;
struct atm_vcc *vcc = ATM_SD(sock);
int error;
lock_sock(sk);
set_bit(ATM_VF_WAITING, &vcc->flags);
sigd_enq(vcc, as_addparty, NULL, NULL,
(struct sockaddr_atmsvc *) sockaddr);
if (flags & O_NONBLOCK) {
error = -EINPROGRESS;
goto out;
}
pr_debug("added wait queue\n");
for (;;) {
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
break;
schedule();
}
finish_wait(sk_sleep(sk), &wait);
error = -xchg(&sk->sk_err_soft, 0);
out:
release_sock(sk);
return error;
}
static int svc_dropparty(struct socket *sock, int ep_ref)
{
DEFINE_WAIT(wait);
struct sock *sk = sock->sk;
struct atm_vcc *vcc = ATM_SD(sock);
int error;
lock_sock(sk);
set_bit(ATM_VF_WAITING, &vcc->flags);
sigd_enq2(vcc, as_dropparty, NULL, NULL, NULL, NULL, ep_ref);
for (;;) {
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
break;
schedule();
}
finish_wait(sk_sleep(sk), &wait);
if (!sigd) {
error = -EUNATCH;
goto out;
}
error = -xchg(&sk->sk_err_soft, 0);
out:
release_sock(sk);
return error;
}
static int svc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
int error, ep_ref;
struct sockaddr_atmsvc sa;
struct atm_vcc *vcc = ATM_SD(sock);
switch (cmd) {
case ATM_ADDPARTY:
if (!test_bit(ATM_VF_SESSION, &vcc->flags))
return -EINVAL;
if (copy_from_user(&sa, (void __user *) arg, sizeof(sa)))
return -EFAULT;
error = svc_addparty(sock, (struct sockaddr *)&sa, sizeof(sa),
0);
break;
case ATM_DROPPARTY:
if (!test_bit(ATM_VF_SESSION, &vcc->flags))
return -EINVAL;
if (copy_from_user(&ep_ref, (void __user *) arg, sizeof(int)))
return -EFAULT;
error = svc_dropparty(sock, ep_ref);
break;
default:
error = vcc_ioctl(sock, cmd, arg);
}
return error;
}
#ifdef CONFIG_COMPAT
static int svc_compat_ioctl(struct socket *sock, unsigned int cmd,
unsigned long arg)
{
/* The definition of ATM_ADDPARTY uses the size of struct atm_iobuf.
But actually it takes a struct sockaddr_atmsvc, which doesn't need
compat handling. So all we have to do is fix up cmd... */
if (cmd == COMPAT_ATM_ADDPARTY)
cmd = ATM_ADDPARTY;
if (cmd == ATM_ADDPARTY || cmd == ATM_DROPPARTY)
return svc_ioctl(sock, cmd, arg);
else
return vcc_compat_ioctl(sock, cmd, arg);
}
#endif /* CONFIG_COMPAT */
static const struct proto_ops svc_proto_ops = {
.family = PF_ATMSVC,
.owner = THIS_MODULE,
.release = svc_release,
.bind = svc_bind,
.connect = svc_connect,
.socketpair = sock_no_socketpair,
.accept = svc_accept,
.getname = svc_getname,
.poll = vcc_poll,
.ioctl = svc_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = svc_compat_ioctl,
#endif
.listen = svc_listen,
.shutdown = svc_shutdown,
.setsockopt = svc_setsockopt,
.getsockopt = svc_getsockopt,
.sendmsg = vcc_sendmsg,
.recvmsg = vcc_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
};
static int svc_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
int error;
if (!net_eq(net, &init_net))
return -EAFNOSUPPORT;
sock->ops = &svc_proto_ops;
error = vcc_create(net, sock, protocol, AF_ATMSVC, kern);
if (error)
return error;
ATM_SD(sock)->local.sas_family = AF_ATMSVC;
ATM_SD(sock)->remote.sas_family = AF_ATMSVC;
return 0;
}
static const struct net_proto_family svc_family_ops = {
.family = PF_ATMSVC,
.create = svc_create,
.owner = THIS_MODULE,
};
/*
* Initialize the ATM SVC protocol family
*/
int __init atmsvc_init(void)
{
return sock_register(&svc_family_ops);
}
void atmsvc_exit(void)
{
sock_unregister(PF_ATMSVC);
}
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