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[kernel] Fix mailbox bugs

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This commit contains a number of related mailbox issues:

- Add extra parameters to mailbox_respond_receive to allow both the
  number of bytes/handles passed in, and the size of the byte/handle
  buffers to be passed in.
- Don't delete mailbox messages on receipt if the caller is waiting on
  reply
- Correctly pass status messages along with a mailbox::replyer object
- Actually wake the calling thread in the mailbox::replyer dtor
- Make sure to release locks _before_ calling thread::wake() on blocked
  threads, as that may cause them to be scheduled ahead of the current
  thread.
This commit is contained in:
Justin C. Miller
2022-02-28 20:16:42 -08:00
parent b8684777e0
commit ef307e8ec6
5 changed files with 44 additions and 21 deletions
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26
src/kernel/objects/mailbox.cpp
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@@ -11,7 +11,8 @@ namespace obj {
static_assert(mailbox::message::slab_size % sizeof(mailbox::message) == 0,
"mailbox message size does not fit cleanly into N pages.");
constexpr uint64_t no_message = 1;
constexpr uint64_t no_message = 0;
constexpr uint64_t has_message = 1;
mailbox::mailbox() :
kobject(kobject::type::mailbox),
@@ -52,26 +53,31 @@ mailbox::send(message *msg)
m_messages.push_back(msg);
thread *t = m_queue.pop_next();
if (t) t->wake();
lock.release();
if (t) t->wake(has_message);
}
bool
mailbox::call(message *msg)
{
uint16_t reply_tag = next_reply_tag();
util::scoped_lock lock {m_message_lock};
if (!++m_next_reply_tag) ++m_next_reply_tag;
msg->reply_tag = m_next_reply_tag;
msg->reply_tag = reply_tag;
thread &current = thread::current();
m_pending.insert(m_next_reply_tag, {&current, msg});
m_pending.insert(reply_tag, {&current, msg});
m_messages.push_back(msg);
thread *t = m_queue.pop_next();
if (t) t->wake();
return (current.block() != no_message);
lock.release();
if (t) t->wake(has_message);
uint64_t result = current.block();
return result == has_message;
}
bool
@@ -113,11 +119,13 @@ mailbox::reply(uint16_t reply_tag)
message *msg = p->msg;
m_pending.erase(reply_tag);
return {msg, caller};
return {msg, caller, has_message};
}
mailbox::replyer::~replyer()
{
if (caller)
caller->wake(status);
}
} // namespace obj