[PATCH v6 0/2] staging: ion: get one device per heap

version 6:
- add platform_bus and platform_bus_type when register Ion devices
  to make them appear in /sys/devices/platform.
- re-order include files in aphabetic order.

version 5:
- create a configuration flag to keep legacy Ion misc device

version 4:
- add a configuration flag to switch between legacy Ion misc device
  and one device per heap version.
  This change has been suggested after Laura talks at XDC 2017.

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.

Until now all ion heaps are addressing using the same device "/dev/ion".
This way of working doesn't allow to give access rights (for example with
SElinux rules) per heap.
This series propose to have one device "/dev/ionX" per heap.
Query heaps informations will be possible on each device node but
allocation request will only be possible if heap_mask_id match with device minor number.

Using legacy Ion misc device is still by setting ION_LEGACY_DEVICE_API
configuration flag.

Benjamin Gaignard (2):
  staging: ion: simplify ioctl args checking function
  staging: ion: create one device entry per heap

 drivers/staging/android/TODO            |  1 -
 drivers/staging/android/ion/Kconfig     |  7 +++++
 drivers/staging/android/ion/ion-ioctl.c | 29 +++++++++++++-----
 drivers/staging/android/ion/ion.c       | 53 ++++++++++++++++++++++++++-------
 drivers/staging/android/ion/ion.h       | 15 ++++++++--
 5 files changed, 84 insertions(+), 21 deletions(-)

-- 
2.7.4

Make arguments checking more easy to read.

Signed-off-by: Benjamin Gaignard <redacted>
Acked-by: Laura Abbott <redacted>
---
 drivers/staging/android/ion/ion-ioctl.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
index d9f8b14..e26b786 100644
--- a/drivers/staging/android/ion/ion-ioctl.c
+++ b/drivers/staging/android/ion/ion-ioctl.c

@@ -27,19 +27,18 @@ union ion_ioctl_arg {
 
 static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
 {
-	int ret = 0;
-
 	switch (cmd) {
 	case ION_IOC_HEAP_QUERY:
-		ret = arg->query.reserved0 != 0;
-		ret |= arg->query.reserved1 != 0;
-		ret |= arg->query.reserved2 != 0;
+		if (arg->query.reserved0 ||
+		    arg->query.reserved1 ||
+		    arg->query.reserved2 )
+			return -EINVAL;
 		break;
 	default:
 		break;
 	}
 
-	return ret ? -EINVAL : 0;
+	return 0;
 }
 
 /* fix up the cases where the ioctl direction bits are incorrect */

-- 
2.7.4

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.

Ion devices are parentless so it is need to add platform_bus as
parent and platform_bus_type as bus to be put in /sys/device/paltform.
Those two parameters need platform_device.h to be included but 
include files weren't in alphabetic order so I reorder them correctly.

Signed-off-by: Benjamin Gaignard <redacted>
---
 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       | 53 ++++++++++++++++++++++++++-------
 drivers/staging/android/ion/ion.h       | 15 ++++++++--
 5 files changed, 79 insertions(+), 15 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/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 93e2c90..dd66f55 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c

@@ -15,31 +15,35 @@
  *
  */
 
+#include <linux/anon_inodes.h>
+#include <linux/debugfs.h>
 #include <linux/device.h>
+#include <linux/dma-buf.h>
 #include <linux/err.h>
+#include <linux/export.h>
 #include <linux/file.h>
 #include <linux/freezer.h>
 #include <linux/fs.h>
-#include <linux/anon_inodes.h>
+#include <linux/idr.h>
 #include <linux/kthread.h>
 #include <linux/list.h>
 #include <linux/memblock.h>
 #include <linux/miscdevice.h>
-#include <linux/export.h>
 #include <linux/mm.h>
 #include <linux/mm_types.h>
+#include <linux/platform_device.h>
 #include <linux/rbtree.h>
-#include <linux/slab.h>
+#include <linux/sched/task.h>
 #include <linux/seq_file.h>
+#include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/vmalloc.h>
-#include <linux/debugfs.h>
-#include <linux/dma-buf.h>
-#include <linux/idr.h>
-#include <linux/sched/task.h>
 
 #include "ion.h"
 
+#define ION_DEV_MAX 32
+#define ION_NAME "ion"
+
 static struct ion_device *internal_dev;
 static int heap_id;
 

@@ -537,15 +541,30 @@ 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 = 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 = &platform_bus;
+	heap->ddev.bus = &platform_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;
 

@@ -583,6 +602,8 @@ void ion_device_add_heap(struct ion_heap *heap)
 
 	dev->heap_cnt++;
 	up_write(&dev->lock);
+
+	return ret;
 }
 EXPORT_SYMBOL(ion_device_add_heap);
 

@@ -595,8 +616,9 @@ 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);

@@ -605,8 +627,19 @@ static int ion_device_create(void)
 		kfree(idev);
 		return ret;
 	}
+#endif
+
+	ret = alloc_chrdev_region(&idev->devt, 0, ION_DEV_MAX, ION_NAME);
+	if (ret) {
+		pr_err("ion: unable to allocate device\n");
+#ifdef CONFIG_ION_LEGACY_DEVICE_API
+		misc_deregister(&idev->dev);
+#endif
+		kfree(idev);
+		return ret;
+	}
 
-	idev->debug_root = debugfs_create_dir("ion", NULL);
+	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;

diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
index 621e5f7..2b00ccb 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"
 

@@ -91,12 +94,16 @@ 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;

@@ -152,6 +159,8 @@ 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 +185,8 @@ 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 +223,7 @@ 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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On Mon, Oct 23, 2017 at 05:55:37PM +0200, 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.

Ion devices are parentless so it is need to add platform_bus as
parent and platform_bus_type as bus to be put in /sys/device/paltform.

nit: paltform -> platform.

Jordan

-- 
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

On 10/23/2017 08:55 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.

I'm wondering if we should always keep /dev/ion for the query
ioctl and just disallow allocation from /dev/ion. I guess
running the query ioctl on /dev/ion0 always wouldn't be too
bad? Anyone else have strong opinions?

Ion devices are parentless so it is need to add platform_bus as
parent and platform_bus_type as bus to be put in /sys/device/paltform.
Those two parameters need platform_device.h to be included but 
include files weren't in alphabetic order so I reorder them correctly.

I'm not a fan of the platform bus but I have mixed feelings about
creating a dedicated bus type. I guess if we really need a bus
type we can do it later?


Thanks,
Laura

On Tue, Oct 31, 2017 at 12:03:35PM -0700, Laura Abbott wrote:

I'm not a fan of the platform bus but I have mixed feelings about
creating a dedicated bus type. I guess if we really need a bus
type we can do it later?

There was a discussion a while ago in the context of I2C/SPI MFDs
which concluded that if you need a bus and it's going to be effectively
noop then you should just use the platform bus as anything else will
consist almost entirely of cut'n'paste from the platform bus with some
light sed usage and code duplication is bad.  It's not super lovely as
it's not actually a memory mapped device but it's the best idea we've
got.

On 10/31/2017 12:11 PM, Mark Brown wrote:

On Tue, Oct 31, 2017 at 12:03:35PM -0700, Laura Abbott wrote:

quoted

I'm not a fan of the platform bus but I have mixed feelings about
creating a dedicated bus type. I guess if we really need a bus
type we can do it later?

There was a discussion a while ago in the context of I2C/SPI MFDs
which concluded that if you need a bus and it's going to be effectively
noop then you should just use the platform bus as anything else will
consist almost entirely of cut'n'paste from the platform bus with some
light sed usage and code duplication is bad.  It's not super lovely as
it's not actually a memory mapped device but it's the best idea we've
got.

Thanks for the pointer.
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On Tue, Oct 31, 2017 at 07:11:53PM +0000, Mark Brown wrote:

On Tue, Oct 31, 2017 at 12:03:35PM -0700, Laura Abbott wrote:

quoted

I'm not a fan of the platform bus but I have mixed feelings about
creating a dedicated bus type. I guess if we really need a bus
type we can do it later?

There was a discussion a while ago in the context of I2C/SPI MFDs
which concluded that if you need a bus and it's going to be effectively
noop then you should just use the platform bus as anything else will
consist almost entirely of cut'n'paste from the platform bus with some
light sed usage and code duplication is bad.  It's not super lovely as
it's not actually a memory mapped device but it's the best idea we've
got.

Ugh, I hate that.  What's wrong with using a "virtual" device instead?

I can create a "virtual" bus for things like this if they really want a
"simple" bus, abusing platform for this is the major reason I hate the
platform bus code...

thanks,

greg k-h

On Thu, Nov 02, 2017 at 11:44:07AM +0100, Greg KH wrote:

On Tue, Oct 31, 2017 at 07:11:53PM +0000, Mark Brown wrote:

quoted

There was a discussion a while ago in the context of I2C/SPI MFDs
which concluded that if you need a bus and it's going to be effectively
noop then you should just use the platform bus as anything else will
consist almost entirely of cut'n'paste from the platform bus with some
light sed usage and code duplication is bad.  It's not super lovely as
it's not actually a memory mapped device but it's the best idea we've
got.

Ugh, I hate that.  What's wrong with using a "virtual" device instead?

It was the duplication, initially everyone was making buses.  

I can create a "virtual" bus for things like this if they really want a
"simple" bus, abusing platform for this is the major reason I hate the
platform bus code...

In the MFD case they're physical devices, they're just usually on the
wrong side of an I2C or SPI link.  Plus MFD already handles platform
devices for things that are memory mapped so it's a bit of a more
natural fit there.

2017-11-02 12:10 GMT+01:00 Mark Brown [off-list ref]:

On Thu, Nov 02, 2017 at 11:44:07AM +0100, Greg KH wrote:

quoted

On Tue, Oct 31, 2017 at 07:11:53PM +0000, Mark Brown wrote:

quoted

quoted

There was a discussion a while ago in the context of I2C/SPI MFDs
which concluded that if you need a bus and it's going to be effectively
noop then you should just use the platform bus as anything else will
consist almost entirely of cut'n'paste from the platform bus with some
light sed usage and code duplication is bad.  It's not super lovely as
it's not actually a memory mapped device but it's the best idea we've
got.

quoted

Ugh, I hate that.  What's wrong with using a "virtual" device instead?

It was the duplication, initially everyone was making buses.

quoted

I can create a "virtual" bus for things like this if they really want a
"simple" bus, abusing platform for this is the major reason I hate the
platform bus code...

In the MFD case they're physical devices, they're just usually on the
wrong side of an I2C or SPI link.  Plus MFD already handles platform
devices for things that are memory mapped so it's a bit of a more
natural fit there.

What I can do is to register an ion bus (like cec one for example),
add one ion parent device so heaps will appear in /sys/bus/ion/ion*
and /sys/devices/ion/ion*

Does that could sound good enough ?

Benjamin
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On Mon, Nov 06, 2017 at 03:42:04PM +0100, Benjamin Gaignard wrote:

2017-11-02 12:10 GMT+01:00 Mark Brown [off-list ref]:

quoted

On Thu, Nov 02, 2017 at 11:44:07AM +0100, Greg KH wrote:

quoted

On Tue, Oct 31, 2017 at 07:11:53PM +0000, Mark Brown wrote:

quoted

quoted

There was a discussion a while ago in the context of I2C/SPI MFDs
which concluded that if you need a bus and it's going to be effectively
noop then you should just use the platform bus as anything else will
consist almost entirely of cut'n'paste from the platform bus with some
light sed usage and code duplication is bad.  It's not super lovely as
it's not actually a memory mapped device but it's the best idea we've
got.

quoted

Ugh, I hate that.  What's wrong with using a "virtual" device instead?

It was the duplication, initially everyone was making buses.

quoted

I can create a "virtual" bus for things like this if they really want a
"simple" bus, abusing platform for this is the major reason I hate the
platform bus code...

In the MFD case they're physical devices, they're just usually on the
wrong side of an I2C or SPI link.  Plus MFD already handles platform
devices for things that are memory mapped so it's a bit of a more
natural fit there.

What I can do is to register an ion bus (like cec one for example),
add one ion parent device so heaps will appear in /sys/bus/ion/ion*
and /sys/devices/ion/ion*

Does that could sound good enough ?

I would like to see that...

thanks,

greg k-h