From 19e394ae7bc9ccfa89f23f5b8c844f724bae3d9b Mon Sep 17 00:00:00 2001
From: Drew Galbraith <dgalbraith33@gmail.com>
Date: Wed, 22 Nov 2023 13:30:59 -0800
Subject: [PATCH] [Yellowstone] Use semaphores for handling yellowstone
 registration.

---
 sys/yellowstone/yellowstone.cpp        |  4 ++--
 sys/yellowstone/yellowstone_server.cpp | 31 ++++++++------------------
 sys/yellowstone/yellowstone_server.h   | 13 +++++------
 3 files changed, 17 insertions(+), 31 deletions(-)

diff --git a/sys/yellowstone/yellowstone.cpp b/sys/yellowstone/yellowstone.cpp
index a7b9571..7100572 100644
--- a/sys/yellowstone/yellowstone.cpp
+++ b/sys/yellowstone/yellowstone.cpp
@@ -27,12 +27,12 @@ uint64_t main(uint64_t port_cap) {
   ASSIGN_OR_RETURN(YellowstoneClient client1, server->CreateClient());
   check(SpawnProcess(gBootDenaliVmmoCap, client1.Capability()));
 
-  check(server->WaitDenaliRegistered());
+  server->WaitDenaliRegistered();
 
   ASSIGN_OR_RETURN(YellowstoneClient client2, server->CreateClient());
   check(SpawnProcess(gBootVictoriaFallsVmmoCap, client2.Capability()));
 
-  check(server->WaitVictoriaFallsRegistered());
+  server->WaitVictoriaFallsRegistered();
 
   dbgln("VFS Available.");
 
diff --git a/sys/yellowstone/yellowstone_server.cpp b/sys/yellowstone/yellowstone_server.cpp
index d6a26c7..e1ca72f 100644
--- a/sys/yellowstone/yellowstone_server.cpp
+++ b/sys/yellowstone/yellowstone_server.cpp
@@ -34,21 +34,12 @@ glcr::ErrorOr<glcr::UniquePtr<YellowstoneServer>> YellowstoneServer::Create() {
   z_cap_t endpoint_cap;
   RET_ERR(ZEndpointCreate(&endpoint_cap));
 
-  ASSIGN_OR_RETURN(Mutex denali_mut, Mutex::Create());
-  RET_ERR(denali_mut.Lock());
-
-  ASSIGN_OR_RETURN(Mutex victoriafalls_mut, Mutex::Create());
-  RET_ERR(victoriafalls_mut.Lock());
-
-  return glcr::UniquePtr<YellowstoneServer>(new YellowstoneServer(
-      endpoint_cap, glcr::Move(denali_mut), glcr::Move(victoriafalls_mut)));
+  return glcr::UniquePtr<YellowstoneServer>(
+      new YellowstoneServer(endpoint_cap));
 }
 
-YellowstoneServer::YellowstoneServer(z_cap_t endpoint_cap, Mutex&& denali_mutex,
-                                     Mutex&& victoriafalls_mutex)
-    : YellowstoneServerBase(endpoint_cap),
-      has_denali_mutex_(glcr::Move(denali_mutex)),
-      has_victoriafalls_mutex_(glcr::Move(victoriafalls_mutex)) {}
+YellowstoneServer::YellowstoneServer(z_cap_t endpoint_cap)
+    : YellowstoneServerBase(endpoint_cap) {}
 
 glcr::ErrorCode YellowstoneServer::HandleGetAhciInfo(const Empty&,
                                                      AhciInfo& info) {
@@ -105,12 +96,12 @@ glcr::ErrorCode YellowstoneServer::HandleRegisterEndpoint(
     device_id_ = part_info_or.value().device_id;
     lba_offset_ = part_info_or.value().partition_lba;
 
-    check(has_denali_mutex_.Release());
+    has_denali_semaphore_.Signal();
   } else if (req.endpoint_name() == "victoriafalls") {
     // FIXME: Probably make a separate copy for use within yellowstone vs
     // transmit to other processes.
     vfs_client_ = glcr::MakeShared<VFSClient>(req.endpoint_capability());
-    check(has_victoriafalls_mutex_.Release());
+    has_victoriafalls_semaphore_.Signal();
   } else {
     dbgln("[WARN] Got endpoint cap type: {}", req.endpoint_name().cstr());
   }
@@ -129,14 +120,10 @@ glcr::ErrorCode YellowstoneServer::HandleGetEndpoint(
   return glcr::OK;
 }
 
-glcr::ErrorCode YellowstoneServer::WaitDenaliRegistered() {
-  RET_ERR(has_denali_mutex_.Lock());
-  return has_denali_mutex_.Release();
-}
+void YellowstoneServer::WaitDenaliRegistered() { has_denali_semaphore_.Wait(); }
 
-glcr::ErrorCode YellowstoneServer::WaitVictoriaFallsRegistered() {
-  RET_ERR(has_victoriafalls_mutex_.Lock());
-  return has_victoriafalls_mutex_.Release();
+void YellowstoneServer::WaitVictoriaFallsRegistered() {
+  has_victoriafalls_semaphore_.Wait();
 }
 
 glcr::SharedPtr<VFSClient> YellowstoneServer::GetVFSClient() {
diff --git a/sys/yellowstone/yellowstone_server.h b/sys/yellowstone/yellowstone_server.h
index c7c279b..b301984 100644
--- a/sys/yellowstone/yellowstone_server.h
+++ b/sys/yellowstone/yellowstone_server.h
@@ -5,8 +5,8 @@
 #include <glacier/memory/unique_ptr.h>
 #include <glacier/status/error_or.h>
 #include <mammoth/endpoint_server.h>
-#include <mammoth/mutex.h>
 #include <mammoth/port_server.h>
+#include <mammoth/semaphore.h>
 #include <mammoth/thread.h>
 #include <victoriafalls/victoriafalls.yunq.client.h>
 
@@ -26,8 +26,8 @@ class YellowstoneServer : public YellowstoneServerBase {
   glcr::ErrorCode HandleGetEndpoint(const GetEndpointRequest&,
                                     Endpoint&) override;
 
-  glcr::ErrorCode WaitDenaliRegistered();
-  glcr::ErrorCode WaitVictoriaFallsRegistered();
+  void WaitDenaliRegistered();
+  void WaitVictoriaFallsRegistered();
 
   glcr::SharedPtr<VFSClient> GetVFSClient();
 
@@ -40,9 +40,8 @@ class YellowstoneServer : public YellowstoneServerBase {
 
   PciReader pci_reader_;
 
-  Mutex has_denali_mutex_;
-  Mutex has_victoriafalls_mutex_;
+  Semaphore has_denali_semaphore_;
+  Semaphore has_victoriafalls_semaphore_;
 
-  YellowstoneServer(z_cap_t endpoint_cap, Mutex&& denali_mutex,
-                    Mutex&& victoriafalls_mutex);
+  YellowstoneServer(z_cap_t endpoint_cap);
 };