rust_binder: introduce TransactionInfo

[ Upstream commit 5326a18 ]

Rust Binder exposes information about transactions that are sent in
various ways: printing to the kernel log, tracepoints, files in
binderfs, and the upcoming netlink support. Currently all these
mechanisms use disparate ways of obtaining the same information, so
let's introduce a single Info struct that collects all the required
information in a single place, so that all of these different mechanisms
can operate in a more uniform way.

For now, the new info struct is only used to replace a few things:
* The BinderTransactionDataSg struct that is passed as an argument to
  several methods is removed as the information is moved into the new
  info struct and passed down that way.
* The oneway spam detection fields on Transaction and Allocation can be
  removed, as the information can be returned to the caller via the
  mutable info struct instead.
But several other uses of the info struct are planned in follow-up
patches.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260306-transaction-info-v1-1-fda58fca558b@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[aliceryhl: explicitly impl Zeroable for UserPtr instead of using derive]
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Darksonn

drivers/android/binder/allocation.rs

@@ -56,7 +56,6 @@ pub(crate) struct Allocation {
     pub(crate) process: Arc<Process>,
     allocation_info: Option<AllocationInfo>,
     free_on_drop: bool,
-    pub(crate) oneway_spam_detected: bool,
     #[allow(dead_code)]
     pub(crate) debug_id: usize,
 }
@@ -68,15 +67,13 @@ impl Allocation {
         offset: usize,
         size: usize,
         ptr: usize,
-        oneway_spam_detected: bool,
     ) -> Self {
         Self {
             process,
             offset,
             size,
             ptr,
             debug_id,
-            oneway_spam_detected,
             allocation_info: None,
             free_on_drop: true,
         }

drivers/android/binder/error.rs

@@ -12,7 +12,7 @@ pub(crate) type BinderResult<T = ()> = core::result::Result<T, BinderError>;
 /// errno.
 pub(crate) struct BinderError {
     pub(crate) reply: u32,
-    source: Option<Error>,
+    pub(crate) source: Option<Error>,
 }
 
 impl BinderError {
@@ -40,14 +40,6 @@ impl BinderError {
     pub(crate) fn is_dead(&self) -> bool {
         self.reply == BR_DEAD_REPLY
     }
-
-    pub(crate) fn as_errno(&self) -> kernel::ffi::c_int {
-        self.source.unwrap_or(EINVAL).to_errno()
-    }
-
-    pub(crate) fn should_pr_warn(&self) -> bool {
-        self.source.is_some()
-    }
 }
 
 /// Convert an errno into a `BinderError` and store the errno used to construct it. The errno

drivers/android/binder/process.rs

@@ -47,6 +47,7 @@ use crate::{
     range_alloc::{RangeAllocator, ReserveNew, ReserveNewArgs},
     stats::BinderStats,
     thread::{PushWorkRes, Thread},
+    transaction::TransactionInfo,
     BinderfsProcFile, DArc, DLArc, DTRWrap, DeliverToRead,
 };
 
@@ -981,16 +982,15 @@ impl Process {
         self: &Arc<Self>,
         debug_id: usize,
         size: usize,
-        is_oneway: bool,
-        from_pid: i32,
+        info: &mut TransactionInfo,
     ) -> BinderResult<NewAllocation> {
         use kernel::page::PAGE_SIZE;
 
         let mut reserve_new_args = ReserveNewArgs {
             debug_id,
             size,
-            is_oneway,
-            pid: from_pid,
+            is_oneway: info.is_oneway(),
+            pid: info.from_pid,
             ..ReserveNewArgs::default()
         };
 
@@ -1006,13 +1006,13 @@ impl Process {
             reserve_new_args = alloc_request.make_alloc()?;
         };
 
+        info.oneway_spam_suspect = new_alloc.oneway_spam_detected;
         let res = Allocation::new(
             self.clone(),
             debug_id,
             new_alloc.offset,
             size,
             addr + new_alloc.offset,
-            new_alloc.oneway_spam_detected,
         );
 
         // This allocation will be marked as in use until the `Allocation` is used to free it.
@@ -1044,7 +1044,7 @@ impl Process {
         let mapping = inner.mapping.as_mut()?;
         let offset = ptr.checked_sub(mapping.address)?;
         let (size, debug_id, odata) = mapping.alloc.reserve_existing(offset).ok()?;
-        let mut alloc = Allocation::new(self.clone(), debug_id, offset, size, ptr, false);
+        let mut alloc = Allocation::new(self.clone(), debug_id, offset, size, ptr);
         if let Some(data) = odata {
             alloc.set_info(data);
         }
@@ -1397,8 +1397,7 @@ impl Process {
                 .alloc
                 .take_for_each(|offset, size, debug_id, odata| {
                     let ptr = offset + address;
-                    let mut alloc =
-                        Allocation::new(self.clone(), debug_id, offset, size, ptr, false);
+                    let mut alloc = Allocation::new(self.clone(), debug_id, offset, size, ptr);
                     if let Some(data) = odata {
                         alloc.set_info(data);
                     }