libbinder: RPC remove isTriggeredPolled
We can get this information in-process, so we can avoid the syscall (and
due to the way it is implemented, we also don't need locking).
Bug: 182940634
Test: binderRpcTest
Change-Id: I3a4f683f71f54972509e071f5dd349e15de54b08
diff --git a/libs/binder/FdTrigger.cpp b/libs/binder/FdTrigger.cpp
index b197a6a..ecf13dc 100644
--- a/libs/binder/FdTrigger.cpp
+++ b/libs/binder/FdTrigger.cpp
@@ -59,19 +59,4 @@
}
}
-android::base::Result<bool> FdTrigger::isTriggeredPolled() {
- pollfd pfd{.fd = mRead.get(), .events = 0, .revents = 0};
- int ret = TEMP_FAILURE_RETRY(poll(&pfd, 1, 0));
- if (ret < 0) {
- return android::base::ErrnoError() << "FdTrigger::isTriggeredPolled: Error in poll()";
- }
- if (ret == 0) {
- return false;
- }
- if (pfd.revents & POLLHUP) {
- return true;
- }
- return android::base::Error() << "FdTrigger::isTriggeredPolled: poll() returns " << pfd.revents;
-}
-
} // namespace android
diff --git a/libs/binder/FdTrigger.h b/libs/binder/FdTrigger.h
index 5f67ba3..a545d6c 100644
--- a/libs/binder/FdTrigger.h
+++ b/libs/binder/FdTrigger.h
@@ -35,7 +35,11 @@
void trigger();
/**
- * Check whether this has been triggered by checking the write end.
+ * Check whether this has been triggered by checking the write end. Note:
+ * this has no internal locking, and it is inherently racey, but this is
+ * okay, because if we accidentally return false when a trigger has already
+ * happened, we can imagine that instead, the scheduler actually executed
+ * the code which is polling isTriggered earlier.
*/
[[nodiscard]] bool isTriggered();
@@ -50,16 +54,6 @@
*/
[[nodiscard]] status_t triggerablePoll(base::borrowed_fd fd, int16_t event);
- /**
- * Check whether this has been triggered by poll()ing the read end.
- *
- * Return:
- * true - triggered
- * false - not triggered
- * error - error when polling
- */
- [[nodiscard]] android::base::Result<bool> isTriggeredPolled();
-
private:
base::unique_fd mWrite;
base::unique_fd mRead;
diff --git a/libs/binder/RpcTransportTls.cpp b/libs/binder/RpcTransportTls.cpp
index 63f9339..23088ad 100644
--- a/libs/binder/RpcTransportTls.cpp
+++ b/libs/binder/RpcTransportTls.cpp
@@ -319,8 +319,6 @@
private:
android::base::unique_fd mSocket;
Ssl mSsl;
-
- static status_t isTriggered(FdTrigger* fdTrigger);
};
// Error code is errno.
@@ -341,15 +339,6 @@
return ret;
}
-status_t RpcTransportTls::isTriggered(FdTrigger* fdTrigger) {
- auto ret = fdTrigger->isTriggeredPolled();
- if (!ret.ok()) {
- ALOGE("%s: %s", __PRETTY_FUNCTION__, ret.error().message().c_str());
- return ret.error().code() == 0 ? UNKNOWN_ERROR : -ret.error().code();
- }
- return *ret ? -ECANCELED : OK;
-}
-
status_t RpcTransportTls::interruptableWriteFully(FdTrigger* fdTrigger, const void* data,
size_t size) {
auto buffer = reinterpret_cast<const uint8_t*>(data);
@@ -359,7 +348,7 @@
// Before doing any I/O, check trigger once. This ensures the trigger is checked at least
// once. The trigger is also checked via triggerablePoll() after every SSL_write().
- if (status_t status = isTriggered(fdTrigger); status != OK) return status;
+ if (fdTrigger->isTriggered()) return -ECANCELED;
while (buffer < end) {
size_t todo = std::min<size_t>(end - buffer, std::numeric_limits<int>::max());
@@ -390,7 +379,7 @@
// Before doing any I/O, check trigger once. This ensures the trigger is checked at least
// once. The trigger is also checked via triggerablePoll() after every SSL_write().
- if (status_t status = isTriggered(fdTrigger); status != OK) return status;
+ if (fdTrigger->isTriggered()) return -ECANCELED;
while (buffer < end) {
size_t todo = std::min<size_t>(end - buffer, std::numeric_limits<int>::max());