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-rw-r--r--net/atm/pppoatm.c68
1 files changed, 63 insertions, 5 deletions
diff --git a/net/atm/pppoatm.c b/net/atm/pppoatm.c
index 226dca989448..8c93267ce969 100644
--- a/net/atm/pppoatm.c
+++ b/net/atm/pppoatm.c
@@ -60,6 +60,8 @@ struct pppoatm_vcc {
struct atm_vcc *atmvcc; /* VCC descriptor */
void (*old_push)(struct atm_vcc *, struct sk_buff *);
void (*old_pop)(struct atm_vcc *, struct sk_buff *);
+ void (*old_release_cb)(struct atm_vcc *);
+ struct module *old_owner;
/* keep old push/pop for detaching */
enum pppoatm_encaps encaps;
atomic_t inflight;
@@ -107,6 +109,24 @@ static void pppoatm_wakeup_sender(unsigned long arg)
ppp_output_wakeup((struct ppp_channel *) arg);
}
+static void pppoatm_release_cb(struct atm_vcc *atmvcc)
+{
+ struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
+
+ /*
+ * As in pppoatm_pop(), it's safe to clear the BLOCKED bit here because
+ * the wakeup *can't* race with pppoatm_send(). They both hold the PPP
+ * channel's ->downl lock. And the potential race with *setting* it,
+ * which leads to the double-check dance in pppoatm_may_send(), doesn't
+ * exist here. In the sock_owned_by_user() case in pppoatm_send(), we
+ * set the BLOCKED bit while the socket is still locked. We know that
+ * ->release_cb() can't be called until that's done.
+ */
+ if (test_and_clear_bit(BLOCKED, &pvcc->blocked))
+ tasklet_schedule(&pvcc->wakeup_tasklet);
+ if (pvcc->old_release_cb)
+ pvcc->old_release_cb(atmvcc);
+}
/*
* This gets called every time the ATM card has finished sending our
* skb. The ->old_pop will take care up normal atm flow control,
@@ -151,12 +171,11 @@ static void pppoatm_unassign_vcc(struct atm_vcc *atmvcc)
pvcc = atmvcc_to_pvcc(atmvcc);
atmvcc->push = pvcc->old_push;
atmvcc->pop = pvcc->old_pop;
+ atmvcc->release_cb = pvcc->old_release_cb;
tasklet_kill(&pvcc->wakeup_tasklet);
ppp_unregister_channel(&pvcc->chan);
atmvcc->user_back = NULL;
kfree(pvcc);
- /* Gee, I hope we have the big kernel lock here... */
- module_put(THIS_MODULE);
}
/* Called when an AAL5 PDU comes in */
@@ -165,9 +184,13 @@ static void pppoatm_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
pr_debug("\n");
if (skb == NULL) { /* VCC was closed */
+ struct module *module;
+
pr_debug("removing ATMPPP VCC %p\n", pvcc);
+ module = pvcc->old_owner;
pppoatm_unassign_vcc(atmvcc);
atmvcc->push(atmvcc, NULL); /* Pass along bad news */
+ module_put(module);
return;
}
atm_return(atmvcc, skb->truesize);
@@ -211,7 +234,7 @@ error:
ppp_input_error(&pvcc->chan, 0);
}
-static inline int pppoatm_may_send(struct pppoatm_vcc *pvcc, int size)
+static int pppoatm_may_send(struct pppoatm_vcc *pvcc, int size)
{
/*
* It's not clear that we need to bother with using atm_may_send()
@@ -269,10 +292,33 @@ static inline int pppoatm_may_send(struct pppoatm_vcc *pvcc, int size)
static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
{
struct pppoatm_vcc *pvcc = chan_to_pvcc(chan);
+ struct atm_vcc *vcc;
+ int ret;
+
ATM_SKB(skb)->vcc = pvcc->atmvcc;
pr_debug("(skb=0x%p, vcc=0x%p)\n", skb, pvcc->atmvcc);
if (skb->data[0] == '\0' && (pvcc->flags & SC_COMP_PROT))
(void) skb_pull(skb, 1);
+
+ vcc = ATM_SKB(skb)->vcc;
+ bh_lock_sock(sk_atm(vcc));
+ if (sock_owned_by_user(sk_atm(vcc))) {
+ /*
+ * Needs to happen (and be flushed, hence test_and_) before we unlock
+ * the socket. It needs to be seen by the time our ->release_cb gets
+ * called.
+ */
+ test_and_set_bit(BLOCKED, &pvcc->blocked);
+ goto nospace;
+ }
+ if (test_bit(ATM_VF_RELEASED, &vcc->flags) ||
+ test_bit(ATM_VF_CLOSE, &vcc->flags) ||
+ !test_bit(ATM_VF_READY, &vcc->flags)) {
+ bh_unlock_sock(sk_atm(vcc));
+ kfree_skb(skb);
+ return DROP_PACKET;
+ }
+
switch (pvcc->encaps) { /* LLC encapsulation needed */
case e_llc:
if (skb_headroom(skb) < LLC_LEN) {
@@ -285,8 +331,10 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
}
consume_skb(skb);
skb = n;
- if (skb == NULL)
+ if (skb == NULL) {
+ bh_unlock_sock(sk_atm(vcc));
return DROP_PACKET;
+ }
} else if (!pppoatm_may_send(pvcc, skb->truesize))
goto nospace;
memcpy(skb_push(skb, LLC_LEN), pppllc, LLC_LEN);
@@ -296,6 +344,7 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
goto nospace;
break;
case e_autodetect:
+ bh_unlock_sock(sk_atm(vcc));
pr_debug("Trying to send without setting encaps!\n");
kfree_skb(skb);
return 1;
@@ -305,9 +354,12 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
ATM_SKB(skb)->atm_options = ATM_SKB(skb)->vcc->atm_options;
pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n",
skb, ATM_SKB(skb)->vcc, ATM_SKB(skb)->vcc->dev);
- return ATM_SKB(skb)->vcc->send(ATM_SKB(skb)->vcc, skb)
+ ret = ATM_SKB(skb)->vcc->send(ATM_SKB(skb)->vcc, skb)
? DROP_PACKET : 1;
+ bh_unlock_sock(sk_atm(vcc));
+ return ret;
nospace:
+ bh_unlock_sock(sk_atm(vcc));
/*
* We don't have space to send this SKB now, but we might have
* already applied SC_COMP_PROT compression, so may need to undo
@@ -362,6 +414,8 @@ static int pppoatm_assign_vcc(struct atm_vcc *atmvcc, void __user *arg)
atomic_set(&pvcc->inflight, NONE_INFLIGHT);
pvcc->old_push = atmvcc->push;
pvcc->old_pop = atmvcc->pop;
+ pvcc->old_owner = atmvcc->owner;
+ pvcc->old_release_cb = atmvcc->release_cb;
pvcc->encaps = (enum pppoatm_encaps) be.encaps;
pvcc->chan.private = pvcc;
pvcc->chan.ops = &pppoatm_ops;
@@ -377,7 +431,9 @@ static int pppoatm_assign_vcc(struct atm_vcc *atmvcc, void __user *arg)
atmvcc->user_back = pvcc;
atmvcc->push = pppoatm_push;
atmvcc->pop = pppoatm_pop;
+ atmvcc->release_cb = pppoatm_release_cb;
__module_get(THIS_MODULE);
+ atmvcc->owner = THIS_MODULE;
/* re-process everything received between connection setup and
backend setup */
@@ -406,6 +462,8 @@ static int pppoatm_ioctl(struct socket *sock, unsigned int cmd,
return -ENOIOCTLCMD;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
+ if (sock->state != SS_CONNECTED)
+ return -EINVAL;
return pppoatm_assign_vcc(atmvcc, argp);
}
case PPPIOCGCHAN:
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