Kernel: Migrate IPv4 socket table locking to ProtectedValue

Author: https://github.com/boricj
Commit: https://github.com/SerenityOS/serenity/commit/583abc27d87
Pull-request: https://github.com/SerenityOS/serenity/pull/8851
Reviewed-by: https://github.com/awesomekling ✅
Reviewed-by: https://github.com/bgianfo

Kernel/Net/IPv4Socket.cpp

@@ -26,11 +26,11 @@
 
 namespace Kernel {
 
-static AK::Singleton<Lockable<HashTable<IPv4Socket*>>> s_table;
+static AK::Singleton<ProtectedValue<HashTable<IPv4Socket*>>> s_table;
 
 using BlockFlags = Thread::FileDescriptionBlocker::BlockFlags;
 
-Lockable<HashTable<IPv4Socket*>>& IPv4Socket::all_sockets()
+ProtectedValue<HashTable<IPv4Socket*>>& IPv4Socket::all_sockets()
 {
     return *s_table;
 }
@@ -77,14 +77,17 @@ IPv4Socket::IPv4Socket(int type, int protocol, NonnullOwnPtr<DoubleBuffer> recei
     if (m_buffer_mode == BufferMode::Bytes) {
         VERIFY(m_scratch_buffer);
     }
-    MutexLocker locker(all_sockets().lock());
-    all_sockets().resource().set(this);
+
+    all_sockets().with_exclusive([&](auto& table) {
+        table.set(this);
+    });
 }
 
 IPv4Socket::~IPv4Socket()
 {
-    MutexLocker locker(all_sockets().lock());
-    all_sockets().resource().remove(this);
+    all_sockets().with_exclusive([&](auto& table) {
+        table.remove(this);
+    });
 }
 
 void IPv4Socket::get_local_address(sockaddr* address, socklen_t* address_size)

Kernel/Net/IPv4Socket.h

@@ -10,7 +10,7 @@
 #include <AK/SinglyLinkedListWithCount.h>
 #include <Kernel/DoubleBuffer.h>
 #include <Kernel/KBuffer.h>
-#include <Kernel/Locking/Lockable.h>
+#include <Kernel/Locking/ProtectedValue.h>
 #include <Kernel/Net/IPv4.h>
 #include <Kernel/Net/IPv4SocketTuple.h>
 #include <Kernel/Net/Socket.h>
@@ -31,7 +31,7 @@ public:
     static KResultOr<NonnullRefPtr<Socket>> create(int type, int protocol);
     virtual ~IPv4Socket() override;
 
-    static Lockable<HashTable<IPv4Socket*>>& all_sockets();
+    static ProtectedValue<HashTable<IPv4Socket*>>& all_sockets();
 
     virtual KResult close() override;
     virtual KResult bind(Userspace<const sockaddr*>, socklen_t) override;

Kernel/Net/NetworkTask.cpp

@@ -223,14 +223,10 @@ void handle_icmp(EthernetFrameHeader const& eth, IPv4Packet const& ipv4_packet,
 
     {
         NonnullRefPtrVector<IPv4Socket> icmp_sockets;
-        {
-            MutexLocker locker(IPv4Socket::all_sockets().lock(), Mutex::Mode::Shared);
-            for (auto* socket : IPv4Socket::all_sockets().resource()) {
-                if (socket->protocol() != (unsigned)IPv4Protocol::ICMP)
-                    continue;
+        IPv4Socket::all_sockets().for_each_shared([&](const auto& socket) {
+            if (socket->protocol() == (unsigned)IPv4Protocol::ICMP)
                 icmp_sockets.append(*socket);
-            }
-        }
+        });
         for (auto& socket : icmp_sockets)
             socket.did_receive(ipv4_packet.source(), 0, { &ipv4_packet, sizeof(IPv4Packet) + ipv4_packet.payload_size() }, packet_timestamp);
     }

Kernel/Net/TCPSocket.h

@@ -11,6 +11,7 @@
 #include <AK/SinglyLinkedList.h>
 #include <AK/WeakPtr.h>
 #include <Kernel/KResult.h>
+#include <Kernel/Locking/Lockable.h>
 #include <Kernel/Net/IPv4Socket.h>
 
 namespace Kernel {