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Commit 8d7ab9a9 authored by Rebecca Schultz Zavin's avatar Rebecca Schultz Zavin Committed by Greg Kroah-Hartman
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gpu: ion: Refactor locking 



Removes contention for lock between allocate and free by reducing
the length of time the lock is held for.  Split out a seperate
lock to protect the list of heaps and replace it with a rwsem since
the list will most likely only be updated during initialization.

Signed-off-by: default avatarRebecca Schultz Zavin <rebecca@android.com>
[jstultz: modified patch to apply to staging directory]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 797a95c4

drivers/staging/android/ion/ion.c

+25 −20
Original line number Diff line number Diff line
@@ -39,14 +39,16 @@ 
 * struct ion_device - the metadata of the ion device node

 * @dev:		the actual misc device

 * @buffers:		an rb tree of all the existing buffers

 * @lock:		lock protecting the buffers & heaps trees

 * @buffer_lock:	lock protecting the tree of buffers

 * @lock:		rwsem protecting the tree of heaps and clients

 * @heaps:		list of all the heaps in the system

 * @user_clients:	list of all the clients created from userspace

 */

struct ion_device {

	struct miscdevice dev;

	struct rb_root buffers;

	struct mutex lock;

	struct mutex buffer_lock;

	struct rw_semaphore lock;

	struct rb_root heaps;

	long (*custom_ioctl) (struct ion_client *client, unsigned int cmd,

			      unsigned long arg);
@@ -205,7 +207,9 @@ static struct ion_buffer *ion_buffer_create(struct ion_heap *heap, 
	   cached mapping that mapping has been invalidated */

	for_each_sg(buffer->sg_table->sgl, sg, buffer->sg_table->nents, i)

		sg_dma_address(sg) = sg_phys(sg);

	mutex_lock(&dev->buffer_lock);

	ion_buffer_add(dev, buffer);

	mutex_unlock(&dev->buffer_lock);

	return buffer;



err:
@@ -224,9 +228,9 @@ static void ion_buffer_destroy(struct kref *kref) 
		buffer->heap->ops->unmap_kernel(buffer->heap, buffer);

	buffer->heap->ops->unmap_dma(buffer->heap, buffer);

	buffer->heap->ops->free(buffer);

	mutex_lock(&dev->lock);

	mutex_lock(&dev->buffer_lock);

	rb_erase(&buffer->node, &dev->buffers);

	mutex_unlock(&dev->lock);

	mutex_unlock(&dev->buffer_lock);

	if (buffer->flags & ION_FLAG_CACHED)

		kfree(buffer->dirty);

	kfree(buffer);
@@ -244,9 +248,9 @@ static int ion_buffer_put(struct ion_buffer *buffer) 


static void ion_buffer_add_to_handle(struct ion_buffer *buffer)

{

	mutex_lock(&buffer->dev->lock);

	mutex_lock(&buffer->lock);

	buffer->handle_count++;

	mutex_unlock(&buffer->dev->lock);

	mutex_unlock(&buffer->lock);

}



static void ion_buffer_remove_from_handle(struct ion_buffer *buffer)
@@ -260,7 +264,7 @@ static void ion_buffer_remove_from_handle(struct ion_buffer *buffer) 
	 * The taskcomm and pid can provide a debug hint as to where this fd

	 * is in the system

	 */

	mutex_lock(&buffer->dev->lock);

	mutex_lock(&buffer->lock);

	buffer->handle_count--;

	BUG_ON(buffer->handle_count < 0);

	if (!buffer->handle_count) {
@@ -270,7 +274,7 @@ static void ion_buffer_remove_from_handle(struct ion_buffer *buffer) 
		get_task_comm(buffer->task_comm, task);

		buffer->pid = task_pid_nr(task);

	}

	mutex_unlock(&buffer->dev->lock);

	mutex_unlock(&buffer->lock);

}



static struct ion_handle *ion_handle_create(struct ion_client *client,
@@ -403,7 +407,7 @@ struct ion_handle *ion_alloc(struct ion_client *client, size_t len, 


	len = PAGE_ALIGN(len);



	mutex_lock(&dev->lock);

	down_read(&dev->lock);

	for (n = rb_first(&dev->heaps); n != NULL; n = rb_next(n)) {

		struct ion_heap *heap = rb_entry(n, struct ion_heap, node);

		/* if the client doesn't support this heap type */
@@ -416,7 +420,7 @@ struct ion_handle *ion_alloc(struct ion_client *client, size_t len, 
		if (!IS_ERR_OR_NULL(buffer))

			break;

	}

	mutex_unlock(&dev->lock);

	up_read(&dev->lock);



	if (buffer == NULL)

		return ERR_PTR(-ENODEV);
@@ -662,7 +666,7 @@ struct ion_client *ion_client_create(struct ion_device *dev, 
	client->task = task;

	client->pid = pid;



	mutex_lock(&dev->lock);

	down_write(&dev->lock);

	p = &dev->clients.rb_node;

	while (*p) {

		parent = *p;
@@ -680,7 +684,7 @@ struct ion_client *ion_client_create(struct ion_device *dev, 
	client->debug_root = debugfs_create_file(debug_name, 0664,

						 dev->debug_root, client,

						 &debug_client_fops);

	mutex_unlock(&dev->lock);

	up_write(&dev->lock);



	return client;

}
@@ -696,12 +700,12 @@ void ion_client_destroy(struct ion_client *client) 
						     node);

		ion_handle_destroy(&handle->ref);

	}

	mutex_lock(&dev->lock);

	down_write(&dev->lock);

	if (client->task)

		put_task_struct(client->task);

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

	debugfs_remove_recursive(client->debug_root);

	mutex_unlock(&dev->lock);

	up_write(&dev->lock);



	kfree(client);

}
@@ -1220,7 +1224,7 @@ static int ion_debug_heap_show(struct seq_file *s, void *unused) 
	seq_printf(s, "----------------------------------------------------\n");

	seq_printf(s, "orphaned allocations (info is from last known client):"

		   "\n");

	mutex_lock(&dev->lock);

	mutex_lock(&dev->buffer_lock);

	for (n = rb_first(&dev->buffers); n; n = rb_next(n)) {

		struct ion_buffer *buffer = rb_entry(n, struct ion_buffer,

						     node);
@@ -1233,7 +1237,7 @@ static int ion_debug_heap_show(struct seq_file *s, void *unused) 
			total_orphaned_size += buffer->size;

		}

	}

	mutex_unlock(&dev->lock);

	mutex_unlock(&dev->buffer_lock);

	seq_printf(s, "----------------------------------------------------\n");

	seq_printf(s, "%16.s %16u\n", "total orphaned",

		   total_orphaned_size);
@@ -1270,7 +1274,7 @@ void ion_device_add_heap(struct ion_device *dev, struct ion_heap *heap) 
		       __func__);



	heap->dev = dev;

	mutex_lock(&dev->lock);

	down_write(&dev->lock);

	while (*p) {

		parent = *p;

		entry = rb_entry(parent, struct ion_heap, node);
@@ -1291,7 +1295,7 @@ void ion_device_add_heap(struct ion_device *dev, struct ion_heap *heap) 
	debugfs_create_file(heap->name, 0664, dev->debug_root, heap,

			    &debug_heap_fops);

end:

	mutex_unlock(&dev->lock);

	up_write(&dev->lock);

}



struct ion_device *ion_device_create(long (*custom_ioctl)
@@ -1322,7 +1326,8 @@ struct ion_device *ion_device_create(long (*custom_ioctl) 


	idev->custom_ioctl = custom_ioctl;

	idev->buffers = RB_ROOT;

	mutex_init(&idev->lock);

	mutex_init(&idev->buffer_lock);

	init_rwsem(&idev->lock);

	idev->heaps = RB_ROOT;

	idev->clients = RB_ROOT;

	return idev;