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Kernel: Use RefPtr instead of LockRefPtr for Custody

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By protecting all the RefPtr<Custody> objects that may be accessed from
multiple threads at the same time (with spinlocks), we remove the need
for using LockRefPtr<Custody> (which is basically a RefPtr with a
built-in spinlock.)
This commit is contained in:
Andreas Kling 2022-08-21 01:04:35 +02:00
parent 5331d243c6
commit 728c3fbd14
23 changed files with 143 additions and 102 deletions
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5
Kernel/Syscalls/chdir.cpp
View file

@ -4,6 +4,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/RefPtr.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Process.h>
@ -15,10 +16,10 @@ ErrorOr<FlatPtr> Process::sys$chdir(Userspace<char const*> user_path, size_t pat
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::rpath));
auto path = TRY(get_syscall_path_argument(user_path, path_length));
auto current_directory = m_current_directory.with([](auto& current_directory) -> NonnullLockRefPtr<Custody> {
auto current_directory = m_current_directory.with([](auto& current_directory) -> NonnullRefPtr<Custody> {
return *current_directory;
});
LockRefPtr<Custody> new_directory = TRY(VirtualFileSystem::the().open_directory(path->view(), *current_directory));
RefPtr<Custody> new_directory = TRY(VirtualFileSystem::the().open_directory(path->view(), *current_directory));
m_current_directory.with([&](auto& current_directory) {
// NOTE: We use swap() here to avoid manipulating the ref counts while holding the lock.
swap(current_directory, new_directory);

2
Kernel/Syscalls/chmod.cpp
View file

@ -18,7 +18,7 @@ ErrorOr<FlatPtr> Process::sys$chmod(Userspace<Syscall::SC_chmod_params const*> u
auto params = TRY(copy_typed_from_user(user_params));
auto path = TRY(get_syscall_path_argument(params.path));
LockRefPtr<Custody> base;
RefPtr<Custody> base;
if (params.dirfd == AT_FDCWD) {
base = current_directory();
} else {

3
Kernel/Syscalls/chown.cpp
View file

@ -4,6 +4,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/RefPtr.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/Library/NonnullLockRefPtrVector.h>
@ -27,7 +28,7 @@ ErrorOr<FlatPtr> Process::sys$chown(Userspace<Syscall::SC_chown_params const*> u
auto params = TRY(copy_typed_from_user(user_params));
auto path = TRY(get_syscall_path_argument(params.path));
LockRefPtr<Custody> base;
RefPtr<Custody> base;
if (params.dirfd == AT_FDCWD) {
base = current_directory();
} else {

2
Kernel/Syscalls/execve.cpp
View file

@ -554,7 +554,7 @@ ErrorOr<void> Process::do_exec(NonnullLockRefPtr<OpenFileDescription> main_progr
m_space = load_result.space.release_nonnull();
m_executable = main_program_description->custody();
m_executable.with([&](auto& executable) { executable = main_program_description->custody(); });
m_arguments = move(arguments);
m_environment = move(environment);

2
Kernel/Syscalls/fork.cpp
View file

@ -28,7 +28,7 @@ ErrorOr<FlatPtr> Process::sys$fork(RegisterState& regs)
};
auto child_name = TRY(m_name->try_clone());
auto child = TRY(Process::try_create(child_first_thread, move(child_name), uid(), gid(), pid(), m_is_kernel_process, current_directory(), m_executable, m_tty, this));
auto child = TRY(Process::try_create(child_first_thread, move(child_name), uid(), gid(), pid(), m_is_kernel_process, current_directory(), executable(), m_tty, this));
// NOTE: All user processes have a leaked ref on them. It's balanced by Thread::WaitBlockerSet::finalize().
child->ref();

3
Kernel/Syscalls/open.cpp
View file

@ -4,6 +4,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/RefPtr.h>
#include <Kernel/Debug.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
@ -54,7 +55,7 @@ ErrorOr<FlatPtr> Process::sys$open(Userspace<Syscall::SC_open_params const*> use
dbgln_if(IO_DEBUG, "sys$open(dirfd={}, path='{}', options={}, mode={})", dirfd, path->view(), options, mode);
auto fd_allocation = TRY(allocate_fd());
LockRefPtr<Custody> base;
RefPtr<Custody> base;
if (dirfd == AT_FDCWD) {
base = current_directory();
} else {

3
Kernel/Syscalls/stat.cpp
View file

@ -4,6 +4,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/RefPtr.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Library/NonnullLockRefPtrVector.h>
@ -29,7 +30,7 @@ ErrorOr<FlatPtr> Process::sys$stat(Userspace<Syscall::SC_stat_params const*> use
auto path = TRY(get_syscall_path_argument(params.path));
LockRefPtr<Custody> base;
RefPtr<Custody> base;
if (params.dirfd == AT_FDCWD) {
base = current_directory();
} else {

2
Kernel/Syscalls/unlink.cpp
View file

@ -19,7 +19,7 @@ ErrorOr<FlatPtr> Process::sys$unlink(int dirfd, Userspace<char const*> user_path
if (flags & ~AT_REMOVEDIR)
return Error::from_errno(EINVAL);
LockRefPtr<Custody> base;
RefPtr<Custody> base;
if (dirfd == AT_FDCWD) {
base = current_directory();
} else {

3
Kernel/Syscalls/unveil.cpp
View file

@ -5,6 +5,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/RefPtr.h>
#include <AK/StringView.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
@ -79,7 +80,7 @@ ErrorOr<FlatPtr> Process::sys$unveil(Userspace<Syscall::SC_unveil_params const*>
// However, if the user specified unveil() with "c" permissions, we don't set errno if ENOENT is encountered,
// because they most likely intend the program to create the file for them later on.
// If this case is encountered, the parent node of the path is returned and the custody of that inode is used instead.
LockRefPtr<Custody> parent_custody; // Parent inode in case of ENOENT
RefPtr<Custody> parent_custody; // Parent inode in case of ENOENT
OwnPtr<KString> new_unveiled_path;
auto custody_or_error = VirtualFileSystem::the().resolve_path_without_veil(path->view(), VirtualFileSystem::the().root_custody(), &parent_custody);
if (!custody_or_error.is_error()) {

2
Kernel/Syscalls/utimensat.cpp
View file

@ -41,7 +41,7 @@ ErrorOr<FlatPtr> Process::sys$utimensat(Userspace<Syscall::SC_utimensat_params c
OwnPtr<KString> path;
LockRefPtr<OpenFileDescription> description;
LockRefPtr<Custody> base;
RefPtr<Custody> base;
auto path_or_error = get_syscall_path_argument(params.path);
if (path_or_error.is_error()) {