ladybird/Kernel/FileSystem/AnonymousFile.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

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/*
* Copyright (c) 2021-2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/FileSystem/AnonymousFile.h>
#include <Kernel/Memory/AnonymousVMObject.h>
#include <Kernel/Process.h>
namespace Kernel {
AnonymousFile::AnonymousFile(NonnullLockRefPtr<Memory::AnonymousVMObject> vmobject)
: m_vmobject(move(vmobject))
{
}
AnonymousFile::~AnonymousFile() = default;
ErrorOr<NonnullLockRefPtr<Memory::VMObject>> AnonymousFile::vmobject_for_mmap(Process&, Memory::VirtualRange const&, u64& offset, bool)
{
if (offset != 0)
return EINVAL;
return m_vmobject;
}
ErrorOr<NonnullOwnPtr<KString>> AnonymousFile::pseudo_path(OpenFileDescription const&) const
{
return KString::try_create(":anonymous-file:"sv);
}
}