Move the channel destroy code into rust_chan.
This lets native code more easily destroy channels since directly deleting a channel is not always the right way to destroy it.
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@ -116,6 +116,41 @@ rust_chan *rust_chan::clone(maybe_proxy<rust_task> *target) {
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return new (target_task) rust_chan(target_task, port, unit_sz);
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}
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/**
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* Cannot Yield: If the task were to unwind, the dropped ref would still
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* appear to be live, causing modify-after-free errors.
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*/
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void rust_chan::destroy() {
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A(task->sched, ref_count == 0,
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"Channel's ref count should be zero.");
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if (is_associated()) {
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if (port->is_proxy()) {
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// Here is a good place to delete the port proxy we allocated
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// in upcall_clone_chan.
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rust_proxy<rust_port> *proxy = port->as_proxy();
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disassociate();
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delete proxy;
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} else {
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// We're trying to delete a channel that another task may be
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// reading from. We have two options:
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//
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// 1. We can flush the channel by blocking in upcall_flush_chan()
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// and resuming only when the channel is flushed. The problem
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// here is that we can get ourselves in a deadlock if the
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// parent task tries to join us.
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//
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// 2. We can leave the channel in a "dormnat" state by not freeing
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// it and letting the receiver task delete it for us instead.
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if (buffer.is_empty() == false) {
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return;
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}
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disassociate();
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}
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}
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delete this;
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}
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//
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// Local Variables:
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// mode: C++
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@ -21,6 +21,9 @@ public:
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void send(void *sptr);
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rust_chan *clone(maybe_proxy<rust_task> *target);
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// Called whenever the channel's ref count drops to zero.
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void destroy();
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};
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//
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@ -126,35 +126,7 @@ void upcall_del_chan(rust_task *task, rust_chan *chan) {
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scoped_lock with(task->kernel->scheduler_lock);
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LOG(task, comm, "upcall del_chan(0x%" PRIxPTR ")", (uintptr_t) chan);
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A(task->sched, chan->ref_count == 0,
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"Channel's ref count should be zero.");
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if (chan->is_associated()) {
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if (chan->port->is_proxy()) {
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// Here is a good place to delete the port proxy we allocated
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// in upcall_clone_chan.
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rust_proxy<rust_port> *proxy = chan->port->as_proxy();
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chan->disassociate();
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delete proxy;
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} else {
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// We're trying to delete a channel that another task may be
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// reading from. We have two options:
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//
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// 1. We can flush the channel by blocking in upcall_flush_chan()
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// and resuming only when the channel is flushed. The problem
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// here is that we can get ourselves in a deadlock if the
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// parent task tries to join us.
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//
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// 2. We can leave the channel in a "dormant" state by not freeing
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// it and letting the receiver task delete it for us instead.
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if (chan->buffer.is_empty() == false) {
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return;
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}
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chan->disassociate();
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}
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}
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delete chan;
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chan->destroy();
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}
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/**
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