Kernel: Make UserOrKernelBuffer R/W helpers return KResultOr<size_t>

This makes error propagation less cumbersome (and also exposed some
places where we were not doing it.)

2 files changed, 8 insertions, 10 deletions

diff --git a/Kernel/FileSystem/InodeWatcher.cpp b/Kernel/FileSystem/InodeWatcher.cpp
index fb7c36739a..29be55b502 100644
--- a/Kernel/FileSystem/InodeWatcher.cpp
+++ b/Kernel/FileSystem/InodeWatcher.cpp
@@ -48,7 +48,7 @@ KResultOr<size_t> InodeWatcher::read(FileDescription&, u64, UserOrKernelBuffer&
     if (buffer_size < bytes_to_write)
         return EINVAL;
 
-    ssize_t nwritten = buffer.write_buffered<MAXIMUM_EVENT_SIZE>(bytes_to_write, [&](u8* data, size_t data_bytes) {
+    auto result = buffer.write_buffered<MAXIMUM_EVENT_SIZE>(bytes_to_write, [&](u8* data, size_t data_bytes) {
         size_t offset = 0;
 
         memcpy(data + offset, &event.wd, sizeof(InodeWatcherEvent::watch_descriptor));
@@ -64,12 +64,10 @@ KResultOr<size_t> InodeWatcher::read(FileDescription&, u64, UserOrKernelBuffer&
             memset(data + offset, 0, sizeof(InodeWatcherEvent::name_length));
         }
 
-        return (ssize_t)data_bytes;
+        return data_bytes;
     });
-    if (nwritten < 0)
-        return KResult((ErrnoCode)-nwritten);
     evaluate_block_conditions();
-    return bytes_to_write;
+    return result;
 }
 
 KResult InodeWatcher::close()
diff --git a/Kernel/FileSystem/ProcFS.cpp b/Kernel/FileSystem/ProcFS.cpp
index 07789b904a..777bb5b936 100644
--- a/Kernel/FileSystem/ProcFS.cpp
+++ b/Kernel/FileSystem/ProcFS.cpp
@@ -903,17 +903,17 @@ static ssize_t write_sys_bool(InodeIdentifier inode_id, const UserOrKernelBuffer
 
     char value = 0;
     bool did_read = false;
-    ssize_t nread = buffer.read_buffered<1>(1, [&](const u8* data, size_t) {
+    auto result = buffer.read_buffered<1>(1, [&](u8 const* data, size_t) {
         if (did_read)
             return 0;
         value = (char)data[0];
         did_read = true;
         return 1;
     });
-    if (nread < 0)
-        return nread;
-    VERIFY(nread == 0 || (nread == 1 && did_read));
-    if (nread == 0 || !(value == '0' || value == '1'))
+    if (result.is_error())
+        return result.error();
+    VERIFY(result.value() == 0 || (result.value() == 1 && did_read));
+    if (result.value() == 0 || !(value == '0' || value == '1'))
         return (ssize_t)size;
 
     auto* lockable_bool = reinterpret_cast<Lockable<bool>*>(variable.address);