From 3bf74c2494148f4de14ad0e59e4b2cd473bb650a Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 24 Aug 2026 10:32:22 +0200
Subject: kernel/fs: devfs: simplify directory listing

---
 kernel/kernel/filesystem/devfs/inode.cpp | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/kernel/kernel/filesystem/devfs/inode.cpp b/kernel/kernel/filesystem/devfs/inode.cpp
index b1ac17c2..67f03768 100644
--- a/kernel/kernel/filesystem/devfs/inode.cpp
+++ b/kernel/kernel/filesystem/devfs/inode.cpp
@@ -47,12 +47,17 @@ namespace kernel::filesystem::devfs
   auto inode::read_directory(directory_listing_cursor position, std::span<directory_listing_entry> entries) const
       -> kstd::result<std::pair<std::size_t, directory_listing_cursor>>
   {
-    auto requested = entries.size();
+    auto const requested = entries.size();
     if (requested == 0)
     {
       return kstd::failure(vfs_errc::invalid_argument);
     }
 
+    if (position == sentinel)
+    {
+      return std::pair{0, sentinel};
+    }
+
     auto devices = kernel::filesystem::device_number_registry::get().all();
     if (devices.empty())
     {
@@ -61,11 +66,12 @@ namespace kernel::filesystem::devfs
 
     std::ranges::stable_sort(devices, std::ranges::less{}, &kernel::filesystem::device_number_registry::entry::number);
 
-    auto device_number = std::bit_cast<kapi::filesystem::device_number>(static_cast<std::uint16_t>(position.value));
-    auto begin = std::ranges::lower_bound(devices, device_number, std::ranges::less{},
-                                          &kernel::filesystem::device_number_registry::entry::number);
-    auto end = std::ranges::end(devices);
-    auto to_read = std::min(requested, static_cast<std::size_t>(std::ranges::distance(begin, end)));
+    auto const device_number = kapi::filesystem::device_number{static_cast<std::uint8_t>(position.value >> 8),
+                                                               static_cast<std::uint8_t>(position.value & 0xff)};
+    auto const begin = std::ranges::lower_bound(devices, device_number, std::ranges::less{},
+                                                &kernel::filesystem::device_number_registry::entry::number);
+    auto const end = std::ranges::end(devices);
+    auto const to_read = std::min(requested, static_cast<std::size_t>(std::ranges::distance(begin, end)));
 
     if (to_read == 0)
     {
@@ -78,14 +84,15 @@ namespace kernel::filesystem::devfs
                                      .inode_number = std::bit_cast<std::uint16_t>(entry.number)};
     });
 
-    auto last_copied = begin + to_read;
+    auto const last_copied = begin + to_read;
     if (last_copied == end)
     {
       return std::pair{to_read, sentinel};
     }
 
-    auto new_cursor =
-        directory_listing_cursor{static_cast<std::uint64_t>(std::bit_cast<std::uint16_t>(last_copied->number))};
+    auto const new_device_number = last_copied->number;
+    auto const new_cursor = directory_listing_cursor{static_cast<std::uint64_t>(new_device_number.minor) |
+                                                     (static_cast<std::uint64_t>(new_device_number.major) << 8)};
     return std::pair{to_read, new_cursor};
   }
 }  // namespace kernel::filesystem::devfs
\ No newline at end of file
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