Kernel: Move device lookup to Device class itself

Previously, VFS stored a list of all devices, and devices had to
register and unregister themselves with it. This cleans up things
a bit.

2 files changed, 33 insertions, 4 deletions

diff --git a/Kernel/Devices/Device.cpp b/Kernel/Devices/Device.cpp
index 39f7c16f4b..86458f77ae 100644
--- a/Kernel/Devices/Device.cpp
+++ b/Kernel/Devices/Device.cpp
@@ -1,17 +1,40 @@
 #include <Kernel/Devices/Device.h>
-#include <Kernel/FileSystem/VirtualFileSystem.h>
+#include <Kernel/FileSystem/InodeMetadata.h>
 #include <LibC/errno_numbers.h>
 
+static HashMap<u32, Device*>* s_all_devices;
+
+HashMap<u32, Device*>& Device::all_devices()
+{
+    if (s_all_devices == nullptr)
+        s_all_devices = new HashMap<u32, Device*>;
+    return *s_all_devices;
+}
+
+void Device::for_each(Function<void(Device&)> callback)
+{
+    for (auto& entry : all_devices())
+        callback(*entry.value);
+}
+
+Device* Device::get_device(unsigned major, unsigned minor)
+{
+    auto it = all_devices().find(encoded_device(major, minor));
+    if (it == all_devices().end())
+        return nullptr;
+    return it->value;
+}
+
 Device::Device(unsigned major, unsigned minor)
     : m_major(major)
     , m_minor(minor)
 {
-    VFS::the().register_device({}, *this);
+    all_devices().set(encoded_device(m_major, m_minor), this);
 }
 
 Device::~Device()
 {
-    VFS::the().unregister_device({}, *this);
+    all_devices().remove(encoded_device(m_major, m_minor));
 }
 
 String Device::absolute_path() const
diff --git a/Kernel/Devices/Device.h b/Kernel/Devices/Device.h
index 9455d4e4a3..cf333e7404 100644
--- a/Kernel/Devices/Device.h
+++ b/Kernel/Devices/Device.h
@@ -2,13 +2,14 @@
 
 // Device is the base class of everything that lives in the /dev directory.
 //
-// All Devices will automatically register with the VFS.
 // To expose a Device to the filesystem, simply pass two unique numbers to the constructor,
 // and then mknod a file in /dev with those numbers.
 //
 // There are two main subclasses:
 //   - BlockDevice (random access)
 //   - CharacterDevice (sequential)
+#include <AK/Function.h>
+#include <AK/HashMap.h>
 #include <Kernel/FileSystem/File.h>
 #include <Kernel/UnixTypes.h>
 
@@ -28,11 +29,16 @@ public:
     virtual bool is_device() const override { return true; }
     virtual bool is_disk_device() const { return false; }
 
+    static void for_each(Function<void(Device&)>);
+    static Device* get_device(unsigned major, unsigned minor);
+
 protected:
     Device(unsigned major, unsigned minor);
     void set_uid(uid_t uid) { m_uid = uid; }
     void set_gid(gid_t gid) { m_gid = gid; }
 
+    static HashMap<u32, Device*>& all_devices();
+
 private:
     unsigned m_major { 0 };
     unsigned m_minor { 0 };