[PATCH 3/3] rust_binder: Update transaction flags to use kernel::impl_flags!
From: Jahnavi MN via B4 Relay
Date: Thu Jul 16 2026 - 09:05:39 EST
From: Jahnavi MN <jahnavimn@xxxxxxxxxx>
- Define `TransactionFlags(u32)` and `TransactionFlag` with 4 variants.
- Change flags field type to `TransactionFlags` in structs.
- Add `is_oneway` helper on `TransactionFlags` to simplify checks.
- Update `can_replace` logic to use type-safe combined flag checks.
- Convert `flags` to `u32` for FFI boundaries and logging.
Signed-off-by: Jahnavi MN <jahnavimn@xxxxxxxxxx>
---
drivers/android/binder/thread.rs | 6 ++--
drivers/android/binder/transaction.rs | 56 ++++++++++++++++++++++++++---------
2 files changed, 45 insertions(+), 17 deletions(-)
diff --git a/drivers/android/binder/thread.rs b/drivers/android/binder/thread.rs
index e5bf1eaeeb17..1d10c6a95ff5 100644
--- a/drivers/android/binder/thread.rs
+++ b/drivers/android/binder/thread.rs
@@ -31,7 +31,7 @@
process::{GetWorkOrRegister, Process},
ptr_align,
stats::GLOBAL_STATS,
- transaction::{Transaction, TransactionInfo},
+ transaction::{Transaction, TransactionFlag, TransactionFlags, TransactionInfo},
BinderReturnWriter, DArc, DLArc, DTRWrap, DeliverCode, DeliverToRead,
};
@@ -1244,7 +1244,7 @@ fn read_transaction_info(
info.from_pid = self.process.task.pid();
info.from_tid = self.id;
info.code = td.transaction_data.code;
- info.flags = td.transaction_data.flags;
+ info.flags = TransactionFlags::from_bits(td.transaction_data.flags);
info.data_ptr = UserPtr::from_addr(trd_data_ptr.buffer as usize);
info.data_size = td.transaction_data.data_size as usize;
info.offsets_ptr = UserPtr::from_addr(trd_data_ptr.offsets as usize);
@@ -1350,7 +1350,7 @@ fn reply_inner(self: &Arc<Self>, info: &mut TransactionInfo) -> BinderResult {
let out = (|| -> BinderResult<_> {
let completion = DTRWrap::arc_try_new(DeliverCode::new(BR_TRANSACTION_COMPLETE))?;
let process = orig.from.process.clone();
- let allow_fds = orig.flags & TF_ACCEPT_FDS != 0;
+ let allow_fds = orig.flags.contains(TransactionFlag::AcceptFds);
let reply = Transaction::new_reply(self, process, info, allow_fds)?;
self.inner.lock().push_work(completion);
orig.from.deliver_reply(Ok(reply), &orig, None);
diff --git a/drivers/android/binder/transaction.rs b/drivers/android/binder/transaction.rs
index afef5b46eac2..4e2ef99e512f 100644
--- a/drivers/android/binder/transaction.rs
+++ b/drivers/android/binder/transaction.rs
@@ -25,6 +25,33 @@
BinderReturnWriter, DArc, DLArc, DTRWrap, DeliverToRead,
};
+kernel::impl_flags!(
+ /// Represents multiple transaction flags.
+ #[derive(Debug, Clone, Default, Copy, PartialEq, Eq, Zeroable)]
+ pub struct TransactionFlags(u32);
+
+ /// Represents a single transaction flag.
+ #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+ pub enum TransactionFlag {
+ OneWay = TF_ONE_WAY,
+ AcceptFds = TF_ACCEPT_FDS,
+ ClearBuf = TF_CLEAR_BUF,
+ UpdateTxn = TF_UPDATE_TXN,
+ }
+);
+
+impl TransactionFlags {
+ /// Creates a `TransactionFlags` from a raw `u32` value.
+ pub(crate) fn from_bits(bits: u32) -> Self {
+ Self(bits)
+ }
+
+ /// Checks if the Oneway flag is set.
+ pub(crate) fn is_oneway(self) -> bool {
+ self.contains(TransactionFlag::OneWay)
+ }
+}
+
#[derive(Zeroable)]
pub(crate) struct TransactionInfo {
pub(crate) from_pid: Pid,
@@ -32,7 +59,7 @@ pub(crate) struct TransactionInfo {
pub(crate) to_pid: Pid,
pub(crate) to_tid: Pid,
pub(crate) code: u32,
- pub(crate) flags: u32,
+ pub(crate) flags: TransactionFlags,
pub(crate) data_ptr: UserPtr,
pub(crate) data_size: usize,
pub(crate) offsets_ptr: UserPtr,
@@ -49,7 +76,7 @@ pub(crate) struct TransactionInfo {
impl TransactionInfo {
#[inline]
pub(crate) fn is_oneway(&self) -> bool {
- self.flags & TF_ONE_WAY != 0
+ self.flags.is_oneway()
}
}
@@ -75,7 +102,7 @@ pub(crate) struct Transaction {
allocation: SpinLock<Option<Allocation>>,
is_outstanding: Atomic<bool>,
code: u32,
- pub(crate) flags: u32,
+ pub(crate) flags: TransactionFlags,
data_size: usize,
offsets_size: usize,
data_address: usize,
@@ -121,7 +148,7 @@ pub(crate) fn new(
}
alloc.set_info_oneway_node(node_ref.node.clone());
}
- if info.flags & TF_CLEAR_BUF != 0 {
+ if info.flags.contains(TransactionFlag::ClearBuf) {
alloc.set_info_clear_on_drop();
}
let target_node = node_ref.node.clone();
@@ -161,7 +188,7 @@ pub(crate) fn new_reply(
return Err(err);
}
};
- if info.flags & TF_CLEAR_BUF != 0 {
+ if info.flags.contains(TransactionFlag::ClearBuf) {
alloc.set_info_clear_on_drop();
}
Ok(DTRWrap::arc_pin_init(pin_init!(Transaction {
@@ -194,7 +221,7 @@ pub(crate) fn debug_print_inner(&self, m: &SeqFile, prefix: &str) {
self.from.id,
self.to.task.pid(),
self.code,
- self.flags,
+ u32::from(self.flags),
self.start_time.elapsed().as_millis(),
);
if let Some(target_node) = &self.target_node {
@@ -273,7 +300,7 @@ pub(crate) fn submit(self: DLArc<Self>, info: &mut TransactionInfo) -> BinderRes
let _t_outdated;
let _oneway_node;
- let oneway = self.flags & TF_ONE_WAY != 0;
+ let oneway = self.flags.is_oneway();
let process = self.to.clone();
let mut process_inner = process.inner.lock();
@@ -284,7 +311,7 @@ pub(crate) fn submit(self: DLArc<Self>, info: &mut TransactionInfo) -> BinderRes
crate::trace::trace_transaction(false, &self, None);
if process_inner.is_frozen.is_frozen() {
process_inner.async_recv = true;
- if self.flags & TF_UPDATE_TXN != 0 {
+ if self.flags.contains(TransactionFlag::UpdateTxn) {
if let Some(t_outdated) =
target_node.take_outdated_transaction(&self, &mut process_inner)
{
@@ -355,7 +382,8 @@ pub(crate) fn can_replace(&self, old: &Transaction) -> bool {
return false;
}
- if self.flags & old.flags & (TF_ONE_WAY | TF_UPDATE_TXN) != (TF_ONE_WAY | TF_UPDATE_TXN) {
+ let required = TransactionFlag::OneWay | TransactionFlag::UpdateTxn;
+ if !(self.flags.contains_all(required) && old.flags.contains_all(required)) {
return false;
}
@@ -392,7 +420,7 @@ fn do_work(
writer: &mut BinderReturnWriter<'_>,
) -> Result<bool> {
let send_failed_reply = ScopeGuard::new(|| {
- if self.target_node.is_some() && self.flags & TF_ONE_WAY == 0 {
+ if self.target_node.is_some() && !self.flags.is_oneway() {
let reply = Err(BR_FAILED_REPLY);
self.from.deliver_reply(reply, &self, None);
}
@@ -415,7 +443,7 @@ fn do_work(
tr.cookie = cookie as uapi::binder_uintptr_t;
};
tr.code = self.code;
- tr.flags = self.flags;
+ tr.flags = u32::from(self.flags);
tr.data_size = self.data_size as uapi::binder_size_t;
tr.data.ptr.buffer = self.data_address as uapi::binder_uintptr_t;
tr.offsets_size = self.offsets_size as uapi::binder_size_t;
@@ -425,7 +453,7 @@ fn do_work(
}
tr.sender_euid = self.sender_euid.into_uid_in_current_ns();
tr.sender_pid = 0;
- if self.target_node.is_some() && self.flags & TF_ONE_WAY == 0 {
+ if self.target_node.is_some() && !self.flags.is_oneway() {
// Not a reply and not one-way.
tr.sender_pid = self.from.process.pid_in_current_ns();
}
@@ -477,7 +505,7 @@ fn cancel(self: DArc<Self>) {
drop(allocation);
// If this is not a reply or oneway transaction, then send a dead reply.
- if self.target_node.is_some() && self.flags & TF_ONE_WAY == 0 {
+ if self.target_node.is_some() && !self.flags.is_oneway() {
let reply = Err(BR_DEAD_REPLY);
self.from.deliver_reply(reply, &self, None);
}
@@ -486,7 +514,7 @@ fn cancel(self: DArc<Self>) {
}
fn should_sync_wakeup(&self) -> bool {
- self.flags & TF_ONE_WAY == 0
+ !self.flags.is_oneway()
}
fn debug_print(&self, m: &SeqFile, _prefix: &str, tprefix: &str) -> Result<()> {
--
2.55.0.229.g6434b31f56-goog