1 files changed, 160 insertions, 69 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index a7ecfde66b7b..764b63a5aade 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -141,7 +141,7 @@ enum {
 };
 static uint32_t binder_debug_mask = BINDER_DEBUG_USER_ERROR |
 	BINDER_DEBUG_FAILED_TRANSACTION | BINDER_DEBUG_DEAD_TRANSACTION;
-module_param_named(debug_mask, binder_debug_mask, uint, S_IWUSR | S_IRUGO);
+module_param_named(debug_mask, binder_debug_mask, uint, 0644);
 
 static char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
 module_param_named(devices, binder_devices_param, charp, 0444);
@@ -160,7 +160,7 @@ static int binder_set_stop_on_user_error(const char *val,
 	return ret;
 }
 module_param_call(stop_on_user_error, binder_set_stop_on_user_error,
-	param_get_int, &binder_stop_on_user_error, S_IWUSR | S_IRUGO);
+	param_get_int, &binder_stop_on_user_error, 0644);
 
 #define binder_debug(mask, x...) \
 	do { \
@@ -249,7 +249,7 @@ static struct binder_transaction_log_entry *binder_transaction_log_add(
 	unsigned int cur = atomic_inc_return(&log->cur);
 
 	if (cur >= ARRAY_SIZE(log->entry))
-		log->full = 1;
+		log->full = true;
 	e = &log->entry[cur % ARRAY_SIZE(log->entry)];
 	WRITE_ONCE(e->debug_id_done, 0);
 	/*
@@ -493,8 +493,6 @@ enum binder_deferred_state {
  *                        (protected by @inner_lock)
  * @todo:                 list of work for this process
  *                        (protected by @inner_lock)
- * @wait:                 wait queue head to wait for proc work
- *                        (invariant after initialized)
  * @stats:                per-process binder statistics
  *                        (atomics, no lock needed)
  * @delivered_death:      list of delivered death notification
@@ -537,7 +535,6 @@ struct binder_proc {
 	bool is_dead;
 
 	struct list_head todo;
-	wait_queue_head_t wait;
 	struct binder_stats stats;
 	struct list_head delivered_death;
 	int max_threads;
@@ -579,6 +576,8 @@ enum {
  *                        (protected by @proc->inner_lock)
  * @todo:                 list of work to do for this thread
  *                        (protected by @proc->inner_lock)
+ * @process_todo:         whether work in @todo should be processed
+ *                        (protected by @proc->inner_lock)
  * @return_error:         transaction errors reported by this thread
  *                        (only accessed by this thread)
  * @reply_error:          transaction errors reported by target thread
@@ -604,6 +603,7 @@ struct binder_thread {
 	bool looper_need_return; /* can be written by other thread */
 	struct binder_transaction *transaction_stack;
 	struct list_head todo;
+	bool process_todo;
 	struct binder_error return_error;
 	struct binder_error reply_error;
 	wait_queue_head_t wait;
@@ -789,6 +789,16 @@ static bool binder_worklist_empty(struct binder_proc *proc,
 	return ret;
 }
 
+/**
+ * binder_enqueue_work_ilocked() - Add an item to the work list
+ * @work:         struct binder_work to add to list
+ * @target_list:  list to add work to
+ *
+ * Adds the work to the specified list. Asserts that work
+ * is not already on a list.
+ *
+ * Requires the proc->inner_lock to be held.
+ */
 static void
 binder_enqueue_work_ilocked(struct binder_work *work,
 			   struct list_head *target_list)
@@ -799,22 +809,56 @@ binder_enqueue_work_ilocked(struct binder_work *work,
 }
 
 /**
- * binder_enqueue_work() - Add an item to the work list
- * @proc:         binder_proc associated with list
+ * binder_enqueue_deferred_thread_work_ilocked() - Add deferred thread work
+ * @thread:       thread to queue work to
  * @work:         struct binder_work to add to list
- * @target_list:  list to add work to
  *
- * Adds the work to the specified list. Asserts that work
- * is not already on a list.
+ * Adds the work to the todo list of the thread. Doesn't set the process_todo
+ * flag, which means that (if it wasn't already set) the thread will go to
+ * sleep without handling this work when it calls read.
+ *
+ * Requires the proc->inner_lock to be held.
  */
 static void
-binder_enqueue_work(struct binder_proc *proc,
-		    struct binder_work *work,
-		    struct list_head *target_list)
+binder_enqueue_deferred_thread_work_ilocked(struct binder_thread *thread,
+					    struct binder_work *work)
 {
-	binder_inner_proc_lock(proc);
-	binder_enqueue_work_ilocked(work, target_list);
-	binder_inner_proc_unlock(proc);
+	binder_enqueue_work_ilocked(work, &thread->todo);
+}
+
+/**
+ * binder_enqueue_thread_work_ilocked() - Add an item to the thread work list
+ * @thread:       thread to queue work to
+ * @work:         struct binder_work to add to list
+ *
+ * Adds the work to the todo list of the thread, and enables processing
+ * of the todo queue.
+ *
+ * Requires the proc->inner_lock to be held.
+ */
+static void
+binder_enqueue_thread_work_ilocked(struct binder_thread *thread,
+				   struct binder_work *work)
+{
+	binder_enqueue_work_ilocked(work, &thread->todo);
+	thread->process_todo = true;
+}
+
+/**
+ * binder_enqueue_thread_work() - Add an item to the thread work list
+ * @thread:       thread to queue work to
+ * @work:         struct binder_work to add to list
+ *
+ * Adds the work to the todo list of the thread, and enables processing
+ * of the todo queue.
+ */
+static void
+binder_enqueue_thread_work(struct binder_thread *thread,
+			   struct binder_work *work)
+{
+	binder_inner_proc_lock(thread->proc);
+	binder_enqueue_thread_work_ilocked(thread, work);
+	binder_inner_proc_unlock(thread->proc);
 }
 
 static void
@@ -940,7 +984,7 @@ err:
 static bool binder_has_work_ilocked(struct binder_thread *thread,
 				    bool do_proc_work)
 {
-	return !binder_worklist_empty_ilocked(&thread->todo) ||
+	return thread->process_todo ||
 		thread->looper_need_return ||
 		(do_proc_work &&
 		 !binder_worklist_empty_ilocked(&thread->proc->todo));
@@ -1228,6 +1272,17 @@ static int binder_inc_node_nilocked(struct binder_node *node, int strong,
 			node->local_strong_refs++;
 		if (!node->has_strong_ref && target_list) {
 			binder_dequeue_work_ilocked(&node->work);
+			/*
+			 * Note: this function is the only place where we queue
+			 * directly to a thread->todo without using the
+			 * corresponding binder_enqueue_thread_work() helper
+			 * functions; in this case it's ok to not set the
+			 * process_todo flag, since we know this node work will
+			 * always be followed by other work that starts queue
+			 * processing: in case of synchronous transactions, a
+			 * BR_REPLY or BR_ERROR; in case of oneway
+			 * transactions, a BR_TRANSACTION_COMPLETE.
+			 */
 			binder_enqueue_work_ilocked(&node->work, target_list);
 		}
 	} else {
@@ -1239,6 +1294,9 @@ static int binder_inc_node_nilocked(struct binder_node *node, int strong,
 					node->debug_id);
 				return -EINVAL;
 			}
+			/*
+			 * See comment above
+			 */
 			binder_enqueue_work_ilocked(&node->work, target_list);
 		}
 	}
@@ -1928,13 +1986,19 @@ static void binder_send_failed_reply(struct binder_transaction *t,
 			binder_pop_transaction_ilocked(target_thread, t);
 			if (target_thread->reply_error.cmd == BR_OK) {
 				target_thread->reply_error.cmd = error_code;
-				binder_enqueue_work_ilocked(
-					&target_thread->reply_error.work,
-					&target_thread->todo);
+				binder_enqueue_thread_work_ilocked(
+					target_thread,
+					&target_thread->reply_error.work);
 				wake_up_interruptible(&target_thread->wait);
 			} else {
-				WARN(1, "Unexpected reply error: %u\n",
-						target_thread->reply_error.cmd);
+				/*
+				 * Cannot get here for normal operation, but
+				 * we can if multiple synchronous transactions
+				 * are sent without blocking for responses.
+				 * Just ignore the 2nd error in this case.
+				 */
+				pr_warn("Unexpected reply error: %u\n",
+					target_thread->reply_error.cmd);
 			}
 			binder_inner_proc_unlock(target_thread->proc);
 			binder_thread_dec_tmpref(target_thread);
@@ -2135,7 +2199,7 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
 	int debug_id = buffer->debug_id;
 
 	binder_debug(BINDER_DEBUG_TRANSACTION,
-		     "%d buffer release %d, size %zd-%zd, failed at %p\n",
+		     "%d buffer release %d, size %zd-%zd, failed at %pK\n",
 		     proc->pid, buffer->debug_id,
 		     buffer->data_size, buffer->offsets_size, failed_at);
 
@@ -2569,20 +2633,18 @@ static bool binder_proc_transaction(struct binder_transaction *t,
 				    struct binder_proc *proc,
 				    struct binder_thread *thread)
 {
-	struct list_head *target_list = NULL;
 	struct binder_node *node = t->buffer->target_node;
 	bool oneway = !!(t->flags & TF_ONE_WAY);
-	bool wakeup = true;
+	bool pending_async = false;
 
 	BUG_ON(!node);
 	binder_node_lock(node);
 	if (oneway) {
 		BUG_ON(thread);
 		if (node->has_async_transaction) {
-			target_list = &node->async_todo;
-			wakeup = false;
+			pending_async = true;
 		} else {
-			node->has_async_transaction = 1;
+			node->has_async_transaction = true;
 		}
 	}
 
@@ -2594,19 +2656,17 @@ static bool binder_proc_transaction(struct binder_transaction *t,
 		return false;
 	}
 
-	if (!thread && !target_list)
+	if (!thread && !pending_async)
 		thread = binder_select_thread_ilocked(proc);
 
 	if (thread)
-		target_list = &thread->todo;
-	else if (!target_list)
-		target_list = &proc->todo;
+		binder_enqueue_thread_work_ilocked(thread, &t->work);
+	else if (!pending_async)
+		binder_enqueue_work_ilocked(&t->work, &proc->todo);
 	else
-		BUG_ON(target_list != &node->async_todo);
-
-	binder_enqueue_work_ilocked(&t->work, target_list);
+		binder_enqueue_work_ilocked(&t->work, &node->async_todo);
 
-	if (wakeup)
+	if (!pending_async)
 		binder_wakeup_thread_ilocked(proc, thread, !oneway /* sync */);
 
 	binder_inner_proc_unlock(proc);
@@ -3101,10 +3161,10 @@ static void binder_transaction(struct binder_proc *proc,
 		}
 	}
 	tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE;
-	binder_enqueue_work(proc, tcomplete, &thread->todo);
 	t->work.type = BINDER_WORK_TRANSACTION;
 
 	if (reply) {
+		binder_enqueue_thread_work(thread, tcomplete);
 		binder_inner_proc_lock(target_proc);
 		if (target_thread->is_dead) {
 			binder_inner_proc_unlock(target_proc);
@@ -3112,13 +3172,21 @@ static void binder_transaction(struct binder_proc *proc,
 		}
 		BUG_ON(t->buffer->async_transaction != 0);
 		binder_pop_transaction_ilocked(target_thread, in_reply_to);
-		binder_enqueue_work_ilocked(&t->work, &target_thread->todo);
+		binder_enqueue_thread_work_ilocked(target_thread, &t->work);
 		binder_inner_proc_unlock(target_proc);
 		wake_up_interruptible_sync(&target_thread->wait);
 		binder_free_transaction(in_reply_to);
 	} else if (!(t->flags & TF_ONE_WAY)) {
 		BUG_ON(t->buffer->async_transaction != 0);
 		binder_inner_proc_lock(proc);
+		/*
+		 * Defer the TRANSACTION_COMPLETE, so we don't return to
+		 * userspace immediately; this allows the target process to
+		 * immediately start processing this transaction, reducing
+		 * latency. We will then return the TRANSACTION_COMPLETE when
+		 * the target replies (or there is an error).
+		 */
+		binder_enqueue_deferred_thread_work_ilocked(thread, tcomplete);
 		t->need_reply = 1;
 		t->from_parent = thread->transaction_stack;
 		thread->transaction_stack = t;
@@ -3132,6 +3200,7 @@ static void binder_transaction(struct binder_proc *proc,
 	} else {
 		BUG_ON(target_node == NULL);
 		BUG_ON(t->buffer->async_transaction != 1);
+		binder_enqueue_thread_work(thread, tcomplete);
 		if (!binder_proc_transaction(t, target_proc, NULL))
 			goto err_dead_proc_or_thread;
 	}
@@ -3210,15 +3279,11 @@ err_invalid_target_handle:
 	BUG_ON(thread->return_error.cmd != BR_OK);
 	if (in_reply_to) {
 		thread->return_error.cmd = BR_TRANSACTION_COMPLETE;
-		binder_enqueue_work(thread->proc,
-				    &thread->return_error.work,
-				    &thread->todo);
+		binder_enqueue_thread_work(thread, &thread->return_error.work);
 		binder_send_failed_reply(in_reply_to, return_error);
 	} else {
 		thread->return_error.cmd = return_error;
-		binder_enqueue_work(thread->proc,
-				    &thread->return_error.work,
-				    &thread->todo);
+		binder_enqueue_thread_work(thread, &thread->return_error.work);
 	}
 }
 
@@ -3424,7 +3489,7 @@ static int binder_thread_write(struct binder_proc *proc,
 				w = binder_dequeue_work_head_ilocked(
 						&buf_node->async_todo);
 				if (!w) {
-					buf_node->has_async_transaction = 0;
+					buf_node->has_async_transaction = false;
 				} else {
 					binder_enqueue_work_ilocked(
 							w, &proc->todo);
@@ -3522,10 +3587,9 @@ static int binder_thread_write(struct binder_proc *proc,
 					WARN_ON(thread->return_error.cmd !=
 						BR_OK);
 					thread->return_error.cmd = BR_ERROR;
-					binder_enqueue_work(
-						thread->proc,
-						&thread->return_error.work,
-						&thread->todo);
+					binder_enqueue_thread_work(
+						thread,
+						&thread->return_error.work);
 					binder_debug(
 						BINDER_DEBUG_FAILED_TRANSACTION,
 						"%d:%d BC_REQUEST_DEATH_NOTIFICATION failed\n",
@@ -3605,9 +3669,9 @@ static int binder_thread_write(struct binder_proc *proc,
 					if (thread->looper &
 					    (BINDER_LOOPER_STATE_REGISTERED |
 					     BINDER_LOOPER_STATE_ENTERED))
-						binder_enqueue_work_ilocked(
-								&death->work,
-								&thread->todo);
+						binder_enqueue_thread_work_ilocked(
+								thread,
+								&death->work);
 					else {
 						binder_enqueue_work_ilocked(
 								&death->work,
@@ -3647,7 +3711,7 @@ static int binder_thread_write(struct binder_proc *proc,
 				}
 			}
 			binder_debug(BINDER_DEBUG_DEAD_BINDER,
-				     "%d:%d BC_DEAD_BINDER_DONE %016llx found %p\n",
+				     "%d:%d BC_DEAD_BINDER_DONE %016llx found %pK\n",
 				     proc->pid, thread->pid, (u64)cookie,
 				     death);
 			if (death == NULL) {
@@ -3662,8 +3726,8 @@ static int binder_thread_write(struct binder_proc *proc,
 				if (thread->looper &
 					(BINDER_LOOPER_STATE_REGISTERED |
 					 BINDER_LOOPER_STATE_ENTERED))
-					binder_enqueue_work_ilocked(
-						&death->work, &thread->todo);
+					binder_enqueue_thread_work_ilocked(
+						thread, &death->work);
 				else {
 					binder_enqueue_work_ilocked(
 							&death->work,
@@ -3837,6 +3901,8 @@ retry:
 			break;
 		}
 		w = binder_dequeue_work_head_ilocked(list);
+		if (binder_worklist_empty_ilocked(&thread->todo))
+			thread->process_todo = false;
 
 		switch (w->type) {
 		case BINDER_WORK_TRANSACTION: {
@@ -4302,8 +4368,29 @@ static int binder_thread_release(struct binder_proc *proc,
 		if (t)
 			spin_lock(&t->lock);
 	}
+
+	/*
+	 * If this thread used poll, make sure we remove the waitqueue
+	 * from any epoll data structures holding it with POLLFREE.
+	 * waitqueue_active() is safe to use here because we're holding
+	 * the inner lock.
+	 */
+	if ((thread->looper & BINDER_LOOPER_STATE_POLL) &&
+	    waitqueue_active(&thread->wait)) {
+		wake_up_poll(&thread->wait, EPOLLHUP | POLLFREE);
+	}
+
 	binder_inner_proc_unlock(thread->proc);
 
+	/*
+	 * This is needed to avoid races between wake_up_poll() above and
+	 * and ep_remove_waitqueue() called for other reasons (eg the epoll file
+	 * descriptor being closed); ep_remove_waitqueue() holds an RCU read
+	 * lock, so we can be sure it's done after calling synchronize_rcu().
+	 */
+	if (thread->looper & BINDER_LOOPER_STATE_POLL)
+		synchronize_rcu();
+
 	if (send_reply)
 		binder_send_failed_reply(send_reply, BR_DEAD_REPLY);
 	binder_release_work(proc, &thread->todo);
@@ -4311,7 +4398,7 @@ static int binder_thread_release(struct binder_proc *proc,
 	return active_transactions;
 }
 
-static unsigned int binder_poll(struct file *filp,
+static __poll_t binder_poll(struct file *filp,
 				struct poll_table_struct *wait)
 {
 	struct binder_proc *proc = filp->private_data;
@@ -4319,6 +4406,8 @@ static unsigned int binder_poll(struct file *filp,
 	bool wait_for_proc_work;
 
 	thread = binder_get_thread(proc);
+	if (!thread)
+		return POLLERR;
 
 	binder_inner_proc_lock(thread->proc);
 	thread->looper |= BINDER_LOOPER_STATE_POLL;
@@ -4329,7 +4418,7 @@ static unsigned int binder_poll(struct file *filp,
 	poll_wait(filp, &thread->wait, wait);
 
 	if (binder_has_work(thread, wait_for_proc_work))
-		return POLLIN;
+		return EPOLLIN;
 
 	return 0;
 }
@@ -4646,7 +4735,7 @@ static int binder_mmap(struct file *filp, struct vm_area_struct *vma)
 	return 0;
 
 err_bad_arg:
-	pr_err("binder_mmap: %d %lx-%lx %s failed %d\n",
+	pr_err("%s: %d %lx-%lx %s failed %d\n", __func__,
 	       proc->pid, vma->vm_start, vma->vm_end, failure_string, ret);
 	return ret;
 }
@@ -4656,7 +4745,7 @@ static int binder_open(struct inode *nodp, struct file *filp)
 	struct binder_proc *proc;
 	struct binder_device *binder_dev;
 
-	binder_debug(BINDER_DEBUG_OPEN_CLOSE, "binder_open: %d:%d\n",
+	binder_debug(BINDER_DEBUG_OPEN_CLOSE, "%s: %d:%d\n", __func__,
 		     current->group_leader->pid, current->pid);
 
 	proc = kzalloc(sizeof(*proc), GFP_KERNEL);
@@ -4695,7 +4784,7 @@ static int binder_open(struct inode *nodp, struct file *filp)
 		 * anyway print all contexts that a given PID has, so this
 		 * is not a problem.
 		 */
-		proc->debugfs_entry = debugfs_create_file(strbuf, S_IRUGO,
+		proc->debugfs_entry = debugfs_create_file(strbuf, 0444,
 			binder_debugfs_dir_entry_proc,
 			(void *)(unsigned long)proc->pid,
 			&binder_proc_fops);
@@ -4962,7 +5051,7 @@ static void print_binder_transaction_ilocked(struct seq_file *m,
 	spin_lock(&t->lock);
 	to_proc = t->to_proc;
 	seq_printf(m,
-		   "%s %d: %p from %d:%d to %d:%d code %x flags %x pri %ld r%d",
+		   "%s %d: %pK from %d:%d to %d:%d code %x flags %x pri %ld r%d",
 		   prefix, t->debug_id, t,
 		   t->from ? t->from->proc->pid : 0,
 		   t->from ? t->from->pid : 0,
@@ -4986,7 +5075,7 @@ static void print_binder_transaction_ilocked(struct seq_file *m,
 	}
 	if (buffer->target_node)
 		seq_printf(m, " node %d", buffer->target_node->debug_id);
-	seq_printf(m, " size %zd:%zd data %p\n",
+	seq_printf(m, " size %zd:%zd data %pK\n",
 		   buffer->data_size, buffer->offsets_size,
 		   buffer->data);
 }
@@ -5524,7 +5613,9 @@ static int __init binder_init(void)
 	struct binder_device *device;
 	struct hlist_node *tmp;
 
-	binder_alloc_shrinker_init();
+	ret = binder_alloc_shrinker_init();
+	if (ret)
+		return ret;
 
 	atomic_set(&binder_transaction_log.cur, ~0U);
 	atomic_set(&binder_transaction_log_failed.cur, ~0U);
@@ -5536,27 +5627,27 @@ static int __init binder_init(void)
 
 	if (binder_debugfs_dir_entry_root) {
 		debugfs_create_file("state",
-				    S_IRUGO,
+				    0444,
 				    binder_debugfs_dir_entry_root,
 				    NULL,
 				    &binder_state_fops);
 		debugfs_create_file("stats",
-				    S_IRUGO,
+				    0444,
 				    binder_debugfs_dir_entry_root,
 				    NULL,
 				    &binder_stats_fops);
 		debugfs_create_file("transactions",
-				    S_IRUGO,
+				    0444,
 				    binder_debugfs_dir_entry_root,
 				    NULL,
 				    &binder_transactions_fops);
 		debugfs_create_file("transaction_log",
-				    S_IRUGO,
+				    0444,
 				    binder_debugfs_dir_entry_root,
 				    &binder_transaction_log,
 				    &binder_transaction_log_fops);
 		debugfs_create_file("failed_transaction_log",
-				    S_IRUGO,
+				    0444,
 				    binder_debugfs_dir_entry_root,
 				    &binder_transaction_log_failed,
 				    &binder_transaction_log_fops);