[PATCH 37/37] binder: remove global binder lock

From: Todd Kjos <tkjos@android.com>
To: gregkh@linuxfoundation.org, arve@android.com,
	devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
	maco@google.com, tkjos@google.com
Subject: [PATCH 37/37] binder: remove global binder lock
Date: Thu, 29 Jun 2017 12:02:11 -0700	[thread overview]
Message-ID: <20170629190211.16927-38-tkjos@google.com> (raw)
In-Reply-To: <20170629190211.16927-1-tkjos@google.com>

Remove global mutex and rely on fine-grained locking

Signed-off-by: Todd Kjos <tkjos@google.com>
---
 drivers/android/binder.c | 46 +++-------------------------------------------
 1 file changed, 3 insertions(+), 43 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 1e50b034d49a..c8e9d5dfcd86 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -80,8 +80,6 @@
 #include "binder_alloc.h"
 #include "binder_trace.h"
 
-static DEFINE_MUTEX(binder_main_lock);
-
 static HLIST_HEAD(binder_deferred_list);
 static DEFINE_MUTEX(binder_deferred_lock);
 
@@ -924,19 +922,6 @@ static long task_close_fd(struct binder_proc *proc, unsigned int fd)
 	return retval;
 }
 
-static inline void binder_lock(const char *tag)
-{
-	trace_binder_lock(tag);
-	mutex_lock(&binder_main_lock);
-	trace_binder_locked(tag);
-}
-
-static inline void binder_unlock(const char *tag)
-{
-	trace_binder_unlock(tag);
-	mutex_unlock(&binder_main_lock);
-}
-
 static void binder_set_nice(long nice)
 {
 	long min_nice;
@@ -3557,8 +3542,6 @@ static int binder_thread_read(struct binder_proc *proc,
 
 	thread->looper |= BINDER_LOOPER_STATE_WAITING;
 
-	binder_unlock(__func__);
-
 	trace_binder_wait_for_work(wait_for_proc_work,
 				   !!thread->transaction_stack,
 				   !binder_worklist_empty(proc, &thread->todo));
@@ -3584,8 +3567,6 @@ static int binder_thread_read(struct binder_proc *proc,
 			ret = wait_event_freezable(thread->wait, binder_has_thread_work(thread));
 	}
 
-	binder_lock(__func__);
-
 	binder_inner_proc_lock(proc);
 	if (wait_for_proc_work)
 		proc->ready_threads--;
@@ -4101,8 +4082,6 @@ static unsigned int binder_poll(struct file *filp,
 	struct binder_thread *thread = NULL;
 	int wait_for_proc_work;
 
-	binder_lock(__func__);
-
 	thread = binder_get_thread(proc);
 
 	binder_inner_proc_lock(thread->proc);
@@ -4110,8 +4089,6 @@ static unsigned int binder_poll(struct file *filp,
 		binder_worklist_empty_ilocked(&thread->todo);
 	binder_inner_proc_unlock(thread->proc);
 
-	binder_unlock(__func__);
-
 	if (wait_for_proc_work) {
 		if (binder_has_proc_work(proc, thread))
 			return POLLIN;
@@ -4256,7 +4233,6 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	if (ret)
 		goto err_unlocked;
 
-	binder_lock(__func__);
 	thread = binder_get_thread(proc);
 	if (thread == NULL) {
 		ret = -ENOMEM;
@@ -4315,7 +4291,6 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 err:
 	if (thread)
 		thread->looper_need_return = false;
-	binder_unlock(__func__);
 	wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
 	if (ret && ret != -ERESTARTSYS)
 		pr_info("%d:%d ioctl %x %lx returned %d\n", proc->pid, current->pid, cmd, arg, ret);
@@ -4421,15 +4396,11 @@ static int binder_open(struct inode *nodp, struct file *filp)
 	proc->context = &binder_dev->context;
 	binder_alloc_init(&proc->alloc);
 
-	binder_lock(__func__);
-
 	binder_stats_created(BINDER_STAT_PROC);
 	proc->pid = current->group_leader->pid;
 	INIT_LIST_HEAD(&proc->delivered_death);
 	filp->private_data = proc;
 
-	binder_unlock(__func__);
-
 	mutex_lock(&binder_procs_lock);
 	hlist_add_head(&proc->proc_node, &binder_procs);
 	mutex_unlock(&binder_procs_lock);
@@ -4655,7 +4626,6 @@ static void binder_deferred_func(struct work_struct *work)
 	int defer;
 
 	do {
-		binder_lock(__func__);
 		mutex_lock(&binder_deferred_lock);
 		if (!hlist_empty(&binder_deferred_list)) {
 			proc = hlist_entry(binder_deferred_list.first,
@@ -4682,7 +4652,6 @@ static void binder_deferred_func(struct work_struct *work)
 		if (defer & BINDER_DEFERRED_RELEASE)
 			binder_deferred_release(proc); /* frees proc */
 
-		binder_unlock(__func__);
 		if (files)
 			put_files_struct(files);
 	} while (proc);
@@ -5097,8 +5066,6 @@ static int binder_state_show(struct seq_file *m, void *unused)
 	struct binder_node *node;
 	struct binder_node *last_node = NULL;
 
-	binder_lock(__func__);
-
 	seq_puts(m, "binder state:\n");
 
 	spin_lock(&binder_dead_nodes_lock);
@@ -5128,7 +5095,7 @@ static int binder_state_show(struct seq_file *m, void *unused)
 	hlist_for_each_entry(proc, &binder_procs, proc_node)
 		print_binder_proc(m, proc, 1);
 	mutex_unlock(&binder_procs_lock);
-	binder_unlock(__func__);
+
 	return 0;
 }
 
@@ -5136,8 +5103,6 @@ static int binder_stats_show(struct seq_file *m, void *unused)
 {
 	struct binder_proc *proc;
 
-	binder_lock(__func__);
-
 	seq_puts(m, "binder stats:\n");
 
 	print_binder_stats(m, "", &binder_stats);
@@ -5146,7 +5111,7 @@ static int binder_stats_show(struct seq_file *m, void *unused)
 	hlist_for_each_entry(proc, &binder_procs, proc_node)
 		print_binder_proc_stats(m, proc);
 	mutex_unlock(&binder_procs_lock);
-	binder_unlock(__func__);
+
 	return 0;
 }
 
@@ -5154,14 +5119,12 @@ static int binder_transactions_show(struct seq_file *m, void *unused)
 {
 	struct binder_proc *proc;
 
-	binder_lock(__func__);
-
 	seq_puts(m, "binder transactions:\n");
 	mutex_lock(&binder_procs_lock);
 	hlist_for_each_entry(proc, &binder_procs, proc_node)
 		print_binder_proc(m, proc, 0);
 	mutex_unlock(&binder_procs_lock);
-	binder_unlock(__func__);
+
 	return 0;
 }
 
@@ -5170,8 +5133,6 @@ static int binder_proc_show(struct seq_file *m, void *unused)
 	struct binder_proc *itr;
 	int pid = (unsigned long)m->private;
 
-	binder_lock(__func__);
-
 	mutex_lock(&binder_procs_lock);
 	hlist_for_each_entry(itr, &binder_procs, proc_node) {
 		if (itr->pid == pid) {
@@ -5181,7 +5142,6 @@ static int binder_proc_show(struct seq_file *m, void *unused)
 	}
 	mutex_unlock(&binder_procs_lock);
 
-	binder_unlock(__func__);
 	return 0;
 }
 
-- 
2.13.2.725.g09c95d1e9-goog
