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Commit c978b8d2 authored by Mitchel Humpherys's avatar Mitchel Humpherys
Browse files

ion: simplify client name uniquification 



The current method of finding a unique serial number for Ion client
names is not straightforward and prone to future breakage. Rather than
parsing all client names and extracting the max out of that just store
the client `id' in a new field in `struct ion_client'.

Change-Id: Ic25008e690ae4f9e3b4c19d1e438b8aaadb36a32
Signed-off-by: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
parent 94c52e4c

drivers/staging/android/ion/ion.c

+29 −34
Original line number Diff line number Diff line
@@ -75,6 +75,8 @@ struct ion_device { 
 * @idr:		an idr space for allocating handle ids

 * @lock:		lock protecting the tree of handles

 * @name:		used for debugging

 * @display_name:	used for debugging (unique version of @name)

 * @display_serial:	used for debugging (to make display_name unique)

 * @task:		used for debugging

 *

 * A client represents a list of buffers this client may access.
@@ -88,6 +90,8 @@ struct ion_client { 
	struct idr idr;

	struct mutex lock;

	char *name;

	char *display_name;

	int display_serial;

	struct task_struct *task;

	pid_t pid;

	struct dentry *debug_root;
@@ -762,33 +766,17 @@ static const struct file_operations debug_client_fops = { 
	.release = single_release,

};



static bool startswith(const char *string, const char *prefix)

{

	size_t l1 = strlen(string);

	size_t l2 = strlen(prefix);

	if (l2 > l1)

		return false;

	return strncmp(string, prefix, min(l1, l2)) == 0;

}



static int ion_get_client_serial(const struct rb_root *root,

					const unsigned char *name)

{

	int serial = -1;

	struct rb_node *node;

	for (node = rb_first(root); node; node = rb_next(node)) {

		int n;

		char *serial_string;

		struct ion_client *client = rb_entry(node, struct ion_client,

						node);

		if (!startswith(client->name, name))

		if (strcmp(client->name, name))

			continue;

		serial_string = strrchr(client->name, '-');

		if (!serial_string)

			continue;

		serial_string++;

		sscanf(serial_string, "%d", &n);

		serial = max(serial, n);

		serial = max(serial, client->display_serial);

	}

	return serial + 1;

}
@@ -802,7 +790,6 @@ struct ion_client *ion_client_create(struct ion_device *dev, 
	struct rb_node *parent = NULL;

	struct ion_client *entry;

	pid_t pid;

	int client_serial;



	if (!name) {

		pr_err("%s: Name cannot be null\n", __func__);
@@ -823,11 +810,8 @@ struct ion_client *ion_client_create(struct ion_device *dev, 
	task_unlock(current->group_leader);



	client = kzalloc(sizeof(struct ion_client), GFP_KERNEL);

	if (!client) {

		if (task)

			put_task_struct(current->group_leader);

		return ERR_PTR(-ENOMEM);

	}

	if (!client)

		goto err_put_task_struct;



	client->dev = dev;

	client->handles = RB_ROOT;
@@ -836,15 +820,17 @@ struct ion_client *ion_client_create(struct ion_device *dev, 


	client->task = task;

	client->pid = pid;

	client->name = kstrdup(name, GFP_KERNEL);

	if (!client->name)

		goto err_free_client;



	down_write(&dev->lock);

	client_serial = ion_get_client_serial(&dev->clients, name);

	client->name = kasprintf(GFP_KERNEL, "%s-%d", name, client_serial);

	if (!client->name) {

	client->display_serial = ion_get_client_serial(&dev->clients, name);

	client->display_name = kasprintf(

		GFP_KERNEL, "%s-%d", name, client->display_serial);

	if (!client->display_name) {

		up_write(&dev->lock);

		put_task_struct(current->group_leader);

		kfree(client);

		return ERR_PTR(-ENOMEM);

		goto err_free_client_name;

	}

	p = &dev->clients.rb_node;

	while (*p) {
@@ -859,20 +845,28 @@ struct ion_client *ion_client_create(struct ion_device *dev, 
	rb_link_node(&client->node, parent, p);

	rb_insert_color(&client->node, &dev->clients);





	client->debug_root = debugfs_create_file(client->name, 0664,

	client->debug_root = debugfs_create_file(client->display_name, 0664,

						dev->clients_debug_root,

						client, &debug_client_fops);

	if (!client->debug_root) {

		char buf[256], *path;

		path = dentry_path(dev->clients_debug_root, buf, 256);

		pr_err("Failed to created client debugfs at %s/%s\n",

			path, client->name);

		pr_err("Failed to create client debugfs at %s/%s\n",

			path, client->display_name);

	}



	up_write(&dev->lock);



	return client;



err_free_client_name:

	kfree(client->name);

err_free_client:

	kfree(client);

err_put_task_struct:

	if (task)

		put_task_struct(current->group_leader);

	return ERR_PTR(-ENOMEM);

}

EXPORT_SYMBOL(ion_client_create);
@@ -898,6 +892,7 @@ void ion_client_destroy(struct ion_client *client) 


	up_write(&dev->lock);



	kfree(client->display_name);

	kfree(client->name);

	kfree(client);

}