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Commit 21ef40a9 authored by Todd Kjos's avatar Todd Kjos
Browse files

FROMLIST: binder: refactor binder_pop_transaction 

(from https://lkml.org/lkml/2017/6/29/754

)

binder_pop_transaction needs to be split into 2 pieces to
to allow the proc lock to be held on entry to dequeue the
transaction stack, but no lock when kfree'ing the transaction.

Split into binder_pop_transaction_locked and binder_free_transaction
(the actual locks are still to be added).

Change-Id: I4b3d21d42ad54031f52cb94ab2b0152812747c38
Signed-off-by: default avatarTodd Kjos <tkjos@google.com>
parent 1cfe6277

drivers/android/binder.c

+15 −15
Original line number Diff line number Diff line
@@ -768,14 +768,16 @@ static int binder_dec_ref(struct binder_ref *ref, int strong) 
static void binder_pop_transaction(struct binder_thread *target_thread,

				   struct binder_transaction *t)

{

	if (target_thread) {

	BUG_ON(!target_thread);

	BUG_ON(target_thread->transaction_stack != t);

	BUG_ON(target_thread->transaction_stack->from != target_thread);

	target_thread->transaction_stack =

		target_thread->transaction_stack->from_parent;

	t->from = NULL;

}

	t->need_reply = 0;



static void binder_free_transaction(struct binder_transaction *t)

{

	if (t->buffer)

		t->buffer->transaction = NULL;

	kfree(t);
@@ -808,6 +810,7 @@ static void binder_send_failed_reply(struct binder_transaction *t, 
				binder_pop_transaction(target_thread, t);

				target_thread->return_error = error_code;

				wake_up_interruptible(&target_thread->wait);

				binder_free_transaction(t);

			} else {

				pr_err("reply failed, target thread, %d:%d, has error code %d already\n",

					target_thread->proc->pid,
@@ -822,7 +825,7 @@ static void binder_send_failed_reply(struct binder_transaction *t, 
			     "send failed reply for transaction %d, target dead\n",

			     t->debug_id);



		binder_pop_transaction(target_thread, t);

		binder_free_transaction(t);

		if (next == NULL) {

			binder_debug(BINDER_DEBUG_DEAD_BINDER,

				     "reply failed, no target thread at root\n");
@@ -1806,6 +1809,7 @@ static void binder_transaction(struct binder_proc *proc, 
	if (reply) {

		BUG_ON(t->buffer->async_transaction != 0);

		binder_pop_transaction(target_thread, in_reply_to);

		binder_free_transaction(in_reply_to);

	} else if (!(t->flags & TF_ONE_WAY)) {

		BUG_ON(t->buffer->async_transaction != 0);

		t->need_reply = 1;
@@ -2635,9 +2639,7 @@ static int binder_thread_read(struct binder_proc *proc, 
			t->to_thread = thread;

			thread->transaction_stack = t;

		} else {

			t->buffer->transaction = NULL;

			kfree(t);

			binder_stats_deleted(BINDER_STAT_TRANSACTION);

			binder_free_transaction(t);

		}

		break;

	}
@@ -2680,9 +2682,7 @@ static void binder_release_work(struct list_head *list) 
				binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,

					"undelivered transaction %d\n",

					t->debug_id);

				t->buffer->transaction = NULL;

				kfree(t);

				binder_stats_deleted(BINDER_STAT_TRANSACTION);

				binder_free_transaction(t);

			}

		} break;

		case BINDER_WORK_TRANSACTION_COMPLETE: {