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Subject[PATCH v3 2/2] staging: ion: create one device entry per heap
Date
Instead a getting 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.
Deivce node major will also change and that may impact init scripts.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
---
version 3:
- change ion_device_add_heap prototype to return a possible error

version 2:
- simplify ioctl check like propose by Dan
- make sure that we don't register more than ION_DEV_MAX heaps

drivers/staging/android/TODO | 1 -
drivers/staging/android/ion/ion-ioctl.c | 11 +++++++++--
drivers/staging/android/ion/ion.c | 27 ++++++++++++++++++++-------
drivers/staging/android/ion/ion.h | 12 ++++++++----
4 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/drivers/staging/android/TODO b/drivers/staging/android/TODO
index 5f14247..d770ffa 100644
--- a/drivers/staging/android/TODO
+++ b/drivers/staging/android/TODO
@@ -9,7 +9,6 @@ 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/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
index e26b786..c8c906c 100644
--- a/drivers/staging/android/ion/ion-ioctl.c
+++ b/drivers/staging/android/ion/ion-ioctl.c
@@ -25,8 +25,11 @@ 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)
{
+ int mask = 1 << iminor(filp->f_inode);
+
switch (cmd) {
case ION_IOC_HEAP_QUERY:
if (arg->query.reserved0 ||
@@ -34,6 +37,10 @@ static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
arg->query.reserved2 )
return -EINVAL;
break;
+ case ION_IOC_ALLOC:
+ if (!(arg->allocation.heap_id_mask & mask))
+ return -EINVAL;
+ break;
default:
break;
}
@@ -69,7 +76,7 @@ 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 93e2c90..cc2d381 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -40,6 +40,8 @@

#include "ion.h"

+#define ION_DEV_MAX 32
+
static struct ion_device *internal_dev;
static int heap_id;

@@ -537,15 +539,28 @@ 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)
+int ion_device_add_heap(struct ion_heap *heap)
{
struct dentry *debug_file;
struct ion_device *dev = internal_dev;
+ int ret;

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.devt = MKDEV(MAJOR(dev->devt), heap_id);
+ dev_set_name(&heap->ddev, "ion%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;

@@ -583,6 +598,8 @@ void ion_device_add_heap(struct ion_heap *heap)

dev->heap_cnt++;
up_write(&dev->lock);
+
+ return 0;
}
EXPORT_SYMBOL(ion_device_add_heap);

@@ -595,13 +612,9 @@ static int ion_device_create(void)
if (!idev)
return -ENOMEM;

- idev->dev.minor = MISC_DYNAMIC_MINOR;
- idev->dev.name = "ion";
- idev->dev.fops = &ion_fops;
- idev->dev.parent = NULL;
- ret = misc_register(&idev->dev);
+ ret = alloc_chrdev_region(&idev->devt, 0, ION_DEV_MAX, "ion");
if (ret) {
- pr_err("ion: failed to register misc device.\n");
+ pr_err("ion: unable to allocate major\n");
kfree(idev);
return ret;
}
diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
index 621e5f7..bb8efc5 100644
--- a/drivers/staging/android/ion/ion.h
+++ b/drivers/staging/android/ion/ion.h
@@ -17,6 +17,7 @@
#ifndef _ION_H
#define _ION_H

+#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/dma-direction.h>
#include <linux/kref.h>
@@ -26,7 +27,6 @@
#include <linux/sched.h>
#include <linux/shrinker.h>
#include <linux/types.h>
-#include <linux/miscdevice.h>

#include "../uapi/ion.h"

@@ -90,13 +90,13 @@ void ion_buffer_destroy(struct ion_buffer *buffer);

/**
* struct ion_device - the metadata of the ion device node
- * @dev: the actual misc device
+ * @dev: the actual 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 {
- struct miscdevice dev;
+ dev_t devt;
struct rb_root buffers;
struct mutex buffer_lock;
struct rw_semaphore lock;
@@ -152,6 +152,8 @@ 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
@@ -176,6 +178,8 @@ 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;
@@ -212,7 +216,7 @@ 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
--
2.7.4
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