linux-kernel - [PATCH] ANDROID: binder: call poll

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Message-Id: <20171009122656.53189-1-maco@android.com>
Date:   Mon,  9 Oct 2017 14:26:56 +0200
From:   Martijn Coenen <maco@...roid.com>
To:     gregkh@...uxfoundation.org, john.stultz@...aro.org,
        tkjos@...gle.com, arve@...roid.com
Cc:     linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org,
        maco@...gle.com, malchev@...gle.com,
        Martijn Coenen <maco@...roid.com>
Subject: [PATCH] ANDROID: binder: call poll_wait() unconditionally.

Because we're not guaranteed that subsequent calls
to poll() will have a poll_table_struct parameter
with _qproc set. When _qproc is not set, poll_wait()
is a noop, and we won't be woken up correctly.

Signed-off-by: Martijn Coenen <maco@...roid.com>
---
 drivers/android/binder.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index d055b3f2a207..99f77fec1aaa 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3623,12 +3623,6 @@ static void binder_stat_br(struct binder_proc *proc,
 	}
 }
 
-static int binder_has_thread_work(struct binder_thread *thread)
-{
-	return !binder_worklist_empty(thread->proc, &thread->todo) ||
-		thread->looper_need_return;
-}
-
 static int binder_put_node_cmd(struct binder_proc *proc,
 			       struct binder_thread *thread,
 			       void __user **ptrp,
@@ -4258,12 +4252,9 @@ static unsigned int binder_poll(struct file *filp,
 
 	binder_inner_proc_unlock(thread->proc);
 
-	if (binder_has_work(thread, wait_for_proc_work))
-		return POLLIN;
-
 	poll_wait(filp, &thread->wait, wait);
 
-	if (binder_has_thread_work(thread))
+	if (binder_has_work(thread, wait_for_proc_work))
 		return POLLIN;
 
 	return 0;
-- 
2.14.2.920.gcf0c67979c-goog