Re: [PATCH v6 2/2] staging: ion: create one device entry per heap

[Laura Abbott <labbott@redhat.com>]

On 11/06/2017 07:59 AM, Benjamin Gaignard wrote:
> Instead a getting only one common device "/dev/ion" for
> all the heaps this patch allow to create one device
> entry ("/dev/ionX") per heap.
> Getting an entry per heap could allow to set security rules
> per heap and global ones for all heaps.
> 
> Allocation requests will be only allowed if the mask_id
> match with device minor.
> Query request could be done on any of the devices.
> 

With this patch, sysfs looks like:

$ ls /sys/devices/
breakpoint ion platform software system virtual

 From an Ion perspective, you can have

Acked-by: Laura Abbott <labbott@redhat.com>

Another Ack for the device model stuff would be good but I'll
assume deafening silence means nobody hates it.

Thanks,
Laura

> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
> ---
>   drivers/staging/android/TODO            |  1 -
>   drivers/staging/android/ion/Kconfig     |  7 ++++
>   drivers/staging/android/ion/ion-ioctl.c | 18 ++++++++--
>   drivers/staging/android/ion/ion.c       | 62 +++++++++++++++++++++++++++++----
>   drivers/staging/android/ion/ion.h       | 15 ++++++--
>   5 files changed, 91 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/staging/android/TODO b/drivers/staging/android/TODO
> index 687e0ea..8a11931 100644
> --- a/drivers/staging/android/TODO
> +++ b/drivers/staging/android/TODO
> @@ -8,7 +8,6 @@ TODO:
>   ion/
>    - Add dt-bindings for remaining heaps (chunk and carveout heaps). This would
>      involve putting appropriate bindings in a memory node for Ion to find.
> - - Split /dev/ion up into multiple nodes (e.g. /dev/ion/heap0)
>    - Better test framework (integration with VGEM was suggested)
>   
>   Please send patches to Greg Kroah-Hartman <greg@kroah.com> and Cc:
> diff --git a/drivers/staging/android/ion/Kconfig b/drivers/staging/android/ion/Kconfig
> index a517b2d..cb4666e 100644
> --- a/drivers/staging/android/ion/Kconfig
> +++ b/drivers/staging/android/ion/Kconfig
> @@ -10,6 +10,13 @@ menuconfig ION
>   	  If you're not using Android its probably safe to
>   	  say N here.
>   
> +config ION_LEGACY_DEVICE_API
> +	bool "Keep using Ion legacy misc device API"
> +	depends on ION
> +	help
> +	  Choose this option to keep using Ion legacy misc device API
> +	  i.e. /dev/ion
> +
>   config ION_SYSTEM_HEAP
>   	bool "Ion system heap"
>   	depends on ION
> diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
> index e26b786..bb5c77b 100644
> --- a/drivers/staging/android/ion/ion-ioctl.c
> +++ b/drivers/staging/android/ion/ion-ioctl.c
> @@ -25,7 +25,8 @@ union ion_ioctl_arg {
>   	struct ion_heap_query query;
>   };
>   
> -static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
> +static int validate_ioctl_arg(struct file *filp,
> +			      unsigned int cmd, union ion_ioctl_arg *arg)
>   {
>   	switch (cmd) {
>   	case ION_IOC_HEAP_QUERY:
> @@ -34,6 +35,19 @@ static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
>   		    arg->query.reserved2 )
>   			return -EINVAL;
>   		break;
> +
> +	case ION_IOC_ALLOC:
> +	{
> +		int mask = 1 << iminor(filp->f_inode);
> +
> +#ifdef CONFIG_ION_LEGACY_DEVICE_API
> +		if (imajor(filp->f_inode) == MISC_MAJOR)
> +			return 0;
> +#endif
> +		if (!(arg->allocation.heap_id_mask & mask))
> +			return -EINVAL;
> +		break;
> +	}
>   	default:
>   		break;
>   	}
> @@ -69,7 +83,7 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>   	if (copy_from_user(&data, (void __user *)arg, _IOC_SIZE(cmd)))
>   		return -EFAULT;
>   
> -	ret = validate_ioctl_arg(cmd, &data);
> +	ret = validate_ioctl_arg(filp, cmd, &data);
>   	if (WARN_ON_ONCE(ret))
>   		return ret;
>   
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index fda9756..2c2568b 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -40,6 +40,9 @@
>   
>   #include "ion.h"
>   
> +#define ION_DEV_MAX 32
> +#define ION_NAME "ion"
> +
>   static struct ion_device *internal_dev;
>   static int heap_id;
>   
> @@ -535,15 +538,38 @@ static int debug_shrink_get(void *data, u64 *val)
>   DEFINE_SIMPLE_ATTRIBUTE(debug_shrink_fops, debug_shrink_get,
>   			debug_shrink_set, "%llu\n");
>   
> -void ion_device_add_heap(struct ion_heap *heap)
> +static struct device ion_bus = {
> +	.init_name = ION_NAME,
> +};
> +
> +static struct bus_type ion_bus_type = {
> +	.name = ION_NAME,
> +};
> +
> +int ion_device_add_heap(struct ion_heap *heap)
>   {
>   	struct dentry *debug_file;
>   	struct ion_device *dev = internal_dev;
> +	int ret = 0;
>   
>   	if (!heap->ops->allocate || !heap->ops->free)
>   		pr_err("%s: can not add heap with invalid ops struct.\n",
>   		       __func__);
>   
> +	if (heap_id >= ION_DEV_MAX)
> +		return -EBUSY;
> +
> +	heap->ddev.parent = &ion_bus;
> +	heap->ddev.bus = &ion_bus_type;
> +	heap->ddev.devt = MKDEV(MAJOR(internal_dev->devt), heap_id);
> +	dev_set_name(&heap->ddev, ION_NAME"%d", heap_id);
> +	device_initialize(&heap->ddev);
> +	cdev_init(&heap->chrdev, &ion_fops);
> +	heap->chrdev.owner = THIS_MODULE;
> +	ret = cdev_device_add(&heap->chrdev, &heap->ddev);
> +	if (ret < 0)
> +		return ret;
> +
>   	spin_lock_init(&heap->free_lock);
>   	heap->free_list_size = 0;
>   
> @@ -581,6 +607,8 @@ void ion_device_add_heap(struct ion_heap *heap)
>   
>   	dev->heap_cnt++;
>   	up_write(&dev->lock);
> +
> +	return ret;
>   }
>   EXPORT_SYMBOL(ion_device_add_heap);
>   
> @@ -593,8 +621,9 @@ static int ion_device_create(void)
>   	if (!idev)
>   		return -ENOMEM;
>   
> +#ifdef CONFIG_ION_LEGACY_DEVICE_API
>   	idev->dev.minor = MISC_DYNAMIC_MINOR;
> -	idev->dev.name = "ion";
> +	idev->dev.name = ION_NAME;
>   	idev->dev.fops = &ion_fops;
>   	idev->dev.parent = NULL;
>   	ret = misc_register(&idev->dev);
> @@ -603,19 +632,38 @@ static int ion_device_create(void)
>   		kfree(idev);
>   		return ret;
>   	}
> +#endif
>   
> -	idev->debug_root = debugfs_create_dir("ion", NULL);
> -	if (!idev->debug_root) {
> +	ret = device_register(&ion_bus);
> +	if (ret)
> +		goto clean_misc;
> +
> +	ret = bus_register(&ion_bus_type);
> +	if (ret)
> +		goto clean_device;
> +
> +	ret = alloc_chrdev_region(&idev->devt, 0, ION_DEV_MAX, ION_NAME);
> +	if (ret)
> +		goto clean_device;
> +
> +	idev->debug_root = debugfs_create_dir(ION_NAME, NULL);
> +	if (!idev->debug_root)
>   		pr_err("ion: failed to create debugfs root directory.\n");
> -		goto debugfs_done;
> -	}
>   
> -debugfs_done:
>   	idev->buffers = RB_ROOT;
>   	mutex_init(&idev->buffer_lock);
>   	init_rwsem(&idev->lock);
>   	plist_head_init(&idev->heaps);
>   	internal_dev = idev;
>   	return 0;
> +
> +clean_device:
> +	device_unregister(&ion_bus);
> +clean_misc:
> +#ifdef CONFIG_ION_LEGACY_DEVICE_API
> +	misc_deregister(&idev->dev);
> +#endif
> +	kfree(idev);
> +	return ret;
>   }
>   subsys_initcall(ion_device_create);
> diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
> index f5f9cd6..4869e96 100644
> --- a/drivers/staging/android/ion/ion.h
> +++ b/drivers/staging/android/ion/ion.h
> @@ -17,16 +17,19 @@
>   #ifndef _ION_H
>   #define _ION_H
>   
> +#include <linux/cdev.h>
>   #include <linux/device.h>
>   #include <linux/dma-direction.h>
>   #include <linux/kref.h>
> +#ifdef CONFIG_ION_LEGACY_DEVICE_API
> +#include <linux/miscdevice.h>
> +#endif
>   #include <linux/mm_types.h>
>   #include <linux/mutex.h>
>   #include <linux/rbtree.h>
>   #include <linux/sched.h>
>   #include <linux/shrinker.h>
>   #include <linux/types.h>
> -#include <linux/miscdevice.h>
>   
>   #include "../uapi/ion.h"
>   
> @@ -92,12 +95,16 @@ void ion_buffer_destroy(struct ion_buffer *buffer);
>   /**
>    * struct ion_device - the metadata of the ion device node
>    * @dev:		the actual misc device
> + * @devt:		Ion device
>    * @buffers:		an rb tree of all the existing buffers
>    * @buffer_lock:	lock protecting the tree of buffers
>    * @lock:		rwsem protecting the tree of heaps and clients
>    */
>   struct ion_device {
> +#ifdef CONFIG_ION_LEGACY_DEVICE_API
>   	struct miscdevice dev;
> +#endif
> +	dev_t devt;
>   	struct rb_root buffers;
>   	struct mutex buffer_lock;
>   	struct rw_semaphore lock;
> @@ -153,6 +160,8 @@ struct ion_heap_ops {
>    * struct ion_heap - represents a heap in the system
>    * @node:		rb node to put the heap on the device's tree of heaps
>    * @dev:		back pointer to the ion_device
> + * @ddev:		device structure
> + * @chrdev:		associated character device
>    * @type:		type of heap
>    * @ops:		ops struct as above
>    * @flags:		flags
> @@ -177,6 +186,8 @@ struct ion_heap_ops {
>   struct ion_heap {
>   	struct plist_node node;
>   	struct ion_device *dev;
> +	struct device ddev;
> +	struct cdev chrdev;
>   	enum ion_heap_type type;
>   	struct ion_heap_ops *ops;
>   	unsigned long flags;
> @@ -213,7 +224,7 @@ bool ion_buffer_fault_user_mappings(struct ion_buffer *buffer);
>    * ion_device_add_heap - adds a heap to the ion device
>    * @heap:		the heap to add
>    */
> -void ion_device_add_heap(struct ion_heap *heap);
> +int ion_device_add_heap(struct ion_heap *heap);
>   
>   /**
>    * some helpers for common operations on buffers using the sg_table
>