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

Laura Abbott <labbott@xxxxxxxxxx> · Thu, 9 Nov 2017 13:17:52 -0800

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@xxxxxxxxxx>

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@xxxxxxxxxx>
---
  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@xxxxxxxxx> 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


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