binder: Eliminate a data copy in RPC transport operations
Switch RpcTransportRaw to use sendmsg() and recvmsg() over
iovecs to send data from multiple buffers to avoid having
to copy all data into a single large buffer.
Bug: 202878542
Test: atest binderRpcTest
Change-Id: I8ba7fa815040555503160ae41888a0b0efe9e5d2
diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index 93ed50e..ace5cd5 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -287,8 +287,8 @@
RpcConnectionHeader header;
if (status == OK) {
- status = client->interruptableReadFully(server->mShutdownTrigger.get(), &header,
- sizeof(header), {});
+ iovec iov{&header, sizeof(header)};
+ status = client->interruptableReadFully(server->mShutdownTrigger.get(), &iov, 1, {});
if (status != OK) {
ALOGE("Failed to read ID for client connecting to RPC server: %s",
statusToString(status).c_str());
@@ -301,8 +301,9 @@
if (header.sessionIdSize > 0) {
if (header.sessionIdSize == kSessionIdBytes) {
sessionId.resize(header.sessionIdSize);
- status = client->interruptableReadFully(server->mShutdownTrigger.get(),
- sessionId.data(), sessionId.size(), {});
+ iovec iov{sessionId.data(), sessionId.size()};
+ status =
+ client->interruptableReadFully(server->mShutdownTrigger.get(), &iov, 1, {});
if (status != OK) {
ALOGE("Failed to read session ID for client connecting to RPC server: %s",
statusToString(status).c_str());
@@ -331,8 +332,8 @@
.version = protocolVersion,
};
- status = client->interruptableWriteFully(server->mShutdownTrigger.get(), &response,
- sizeof(response), {});
+ iovec iov{&response, sizeof(response)};
+ status = client->interruptableWriteFully(server->mShutdownTrigger.get(), &iov, 1, {});
if (status != OK) {
ALOGE("Failed to send new session response: %s", statusToString(status).c_str());
// still need to cleanup before we can return