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From:   Benjamin Gaignard <benjamin.gaignard@linaro.org>
Date:   Mon, 27 Nov 2017 11:46:18 +0100
Message-ID: <CA+M3ks6vP+W77QBzbczxzcV7YZCoBusC=wgjZPUNLrCYFFDARA@mail.gmail.com>
Subject: Re: [PATCH v6 2/2] staging: ion: create one device entry per heap
To:     Laura Abbott <labbott@redhat.com>
Cc:     Sumit Semwal <sumit.semwal@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>,
        Riley Andrews <riandrews@android.com>,
        Mark Brown <broonie@kernel.org>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        driverdevel <devel@driverdev.osuosl.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        linux-api@vger.kernel.org
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Sender: linux-kernel-owner@vger.kernel.org
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2017-11-09 22:17 GMT+01:00 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.

Greg, can we get your point of view of this ?

Thanks,
Benjamin

>
> 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
>>
>

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