ladybird/Kernel/FileSystem/File.cpp
Andreas Kling 30861daa93 Kernel: Simplify the File memory-mapping API
Before this change, we had File::mmap() which did all the work of
setting up a VMObject, and then creating a Region in the current
process's address space.

This patch simplifies the interface by removing the region part.
Files now only have to return a suitable VMObject from
vmobject_for_mmap(), and then sys$mmap() itself will take care of
actually mapping it into the address space.

This fixes an issue where we'd try to block on I/O (for inode metadata
lookup) while holding the address space spinlock. It also reduces time
spent holding the address space lock.
2022-08-24 14:57:51 +02:00

54 lines
1.1 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/StringView.h>
#include <AK/Userspace.h>
#include <Kernel/FileSystem/File.h>
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/Process.h>
namespace Kernel {
File::File() = default;
File::~File() = default;
ErrorOr<NonnullLockRefPtr<OpenFileDescription>> File::open(int options)
{
auto description = OpenFileDescription::try_create(*this);
if (!description.is_error()) {
description.value()->set_rw_mode(options);
description.value()->set_file_flags(options);
}
return description;
}
ErrorOr<void> File::close()
{
return {};
}
ErrorOr<void> File::ioctl(OpenFileDescription&, unsigned, Userspace<void*>)
{
return ENOTTY;
}
ErrorOr<NonnullLockRefPtr<Memory::VMObject>> File::vmobject_for_mmap(Process&, Memory::VirtualRange const&, u64&, bool)
{
return ENODEV;
}
ErrorOr<void> File::attach(OpenFileDescription&)
{
m_attach_count++;
return {};
}
void File::detach(OpenFileDescription&)
{
m_attach_count--;
}
}