Commit ac4812c5 authored by Martijn Coenen's avatar Martijn Coenen Committed by Greg Kroah-Hartman
Browse files

binder: Support multiple /dev instances 



Add a new module parameter 'devices', that can be
used to specify the names of the binder device
nodes we want to populate in /dev.

Each device node has its own context manager, and
is therefore logically separated from all the other
device nodes.

The config option CONFIG_ANDROID_BINDER_DEVICES can
be used to set the default value of the parameter.

This approach was favored over using IPC namespaces,
mostly because we require a single process to be a
part of multiple binder contexts, which seemed harder
to achieve with namespaces.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Martijn Coenen <maco@google.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Serban Constantinescu <serban.constantinescu@arm.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Rom Lemarchand <romlem@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: default avatarMartijn Coenen <maco@google.com>
[jstultz: minor checkpatch warning fix]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 14db3181

drivers/android/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -19,6 +19,18 @@ config ANDROID_BINDER_IPC 
	  Android process, using Binder to identify, invoke and pass arguments

	  between said processes.



config ANDROID_BINDER_DEVICES

	string "Android Binder devices"

	depends on ANDROID_BINDER_IPC

	default "binder"

	---help---

	  Default value for the binder.devices parameter.



	  The binder.devices parameter is a comma-separated list of strings

	  that specifies the names of the binder device nodes that will be

	  created. Each binder device has its own context manager, and is

	  therefore logically separated from the other devices.



config ANDROID_BINDER_IPC_32BIT

	bool

	depends on !64BIT && ANDROID_BINDER_IPC

drivers/android/binder.c

+72 −11
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ static DEFINE_MUTEX(binder_main_lock); 
static DEFINE_MUTEX(binder_deferred_lock);

static DEFINE_MUTEX(binder_mmap_lock);



static HLIST_HEAD(binder_devices);

static HLIST_HEAD(binder_procs);

static HLIST_HEAD(binder_deferred_list);

static HLIST_HEAD(binder_dead_nodes);
@@ -113,6 +114,9 @@ module_param_named(debug_mask, binder_debug_mask, uint, S_IWUSR | S_IRUGO); 
static bool binder_debug_no_lock;

module_param_named(proc_no_lock, binder_debug_no_lock, bool, S_IWUSR | S_IRUGO);



static char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;

module_param_named(devices, binder_devices_param, charp, 0444);



static DECLARE_WAIT_QUEUE_HEAD(binder_user_error_wait);

static int binder_stop_on_user_error;
@@ -220,9 +224,10 @@ struct binder_context { 
	const char *name;

};



static struct binder_context global_context = {

	.binder_context_mgr_uid = INVALID_UID,

	.name = "binder",

struct binder_device {

	struct hlist_node hlist;

	struct miscdevice miscdev;

	struct binder_context context;

};



struct binder_work {
@@ -3047,6 +3052,7 @@ err_bad_arg: 
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",

		     current->group_leader->pid, current->pid);
@@ -3057,10 +3063,12 @@ static int binder_open(struct inode *nodp, struct file *filp) 
	get_task_struct(current);

	proc->tsk = current;

	proc->vma_vm_mm = current->mm;

	proc->context = &global_context;

	INIT_LIST_HEAD(&proc->todo);

	init_waitqueue_head(&proc->wait);

	proc->default_priority = task_nice(current);

	binder_dev = container_of(filp->private_data, struct binder_device,

				  miscdev);

	proc->context = &binder_dev->context;



	binder_lock(__func__);
@@ -3767,26 +3775,50 @@ static const struct file_operations binder_fops = { 
	.release = binder_release,

};



static struct miscdevice binder_miscdev = {

	.minor = MISC_DYNAMIC_MINOR,

	.name = "binder",

	.fops = &binder_fops

};



BINDER_DEBUG_ENTRY(state);

BINDER_DEBUG_ENTRY(stats);

BINDER_DEBUG_ENTRY(transactions);

BINDER_DEBUG_ENTRY(transaction_log);



static int __init init_binder_device(const char *name)

{

	int ret;

	struct binder_device *binder_device;



	binder_device = kzalloc(sizeof(*binder_device), GFP_KERNEL);

	if (!binder_device)

		return -ENOMEM;



	binder_device->miscdev.fops = &binder_fops;

	binder_device->miscdev.minor = MISC_DYNAMIC_MINOR;

	binder_device->miscdev.name = name;



	binder_device->context.binder_context_mgr_uid = INVALID_UID;

	binder_device->context.name = name;



	ret = misc_register(&binder_device->miscdev);

	if (ret < 0) {

		kfree(binder_device);

		return ret;

	}



	hlist_add_head(&binder_device->hlist, &binder_devices);



	return ret;

}



static int __init binder_init(void)

{

	int ret;

	char *device_name, *device_names;

	struct binder_device *device;

	struct hlist_node *tmp;



	binder_debugfs_dir_entry_root = debugfs_create_dir("binder", NULL);

	if (binder_debugfs_dir_entry_root)

		binder_debugfs_dir_entry_proc = debugfs_create_dir("proc",

						 binder_debugfs_dir_entry_root);

	ret = misc_register(&binder_miscdev);



	if (binder_debugfs_dir_entry_root) {

		debugfs_create_file("state",

				    S_IRUGO,
@@ -3814,6 +3846,35 @@ static int __init binder_init(void) 
				    &binder_transaction_log_failed,

				    &binder_transaction_log_fops);

	}



	/*

	 * Copy the module_parameter string, because we don't want to

	 * tokenize it in-place.

	 */

	device_names = kzalloc(strlen(binder_devices_param) + 1, GFP_KERNEL);

	if (!device_names) {

		ret = -ENOMEM;

		goto err_alloc_device_names_failed;

	}

	strcpy(device_names, binder_devices_param);



	while ((device_name = strsep(&device_names, ","))) {

		ret = init_binder_device(device_name);

		if (ret)

			goto err_init_binder_device_failed;

	}



	return ret;



err_init_binder_device_failed:

	hlist_for_each_entry_safe(device, tmp, &binder_devices, hlist) {

		misc_deregister(&device->miscdev);

		hlist_del(&device->hlist);

		kfree(device);

	}

err_alloc_device_names_failed:

	debugfs_remove_recursive(binder_debugfs_dir_entry_root);



	return ret;

}

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