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SubjectRe: [PATCH] staging: ion: create one device entry per heap
On Tue, Sep 19, 2017 at 1:07 PM, Benjamin Gaignard
<benjamin.gaignard@linaro.org> wrote:
> 2017-09-19 11:40 GMT+02:00 Dan Carpenter <dan.carpenter@oracle.com>:
>> On Mon, Sep 18, 2017 at 04:58:46PM +0200, Benjamin Gaignard wrote:
>>> -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 ret = 0;
>>> + int mask = 1 << iminor(filp->f_inode);
>>>
>>> switch (cmd) {
>>> case ION_IOC_HEAP_QUERY:
>>> @@ -35,6 +37,9 @@ static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
>>> ret |= arg->query.reserved1 != 0;
>>> ret |= arg->query.reserved2 != 0;
>>> break;
>>> + case ION_IOC_ALLOC:
>>> + ret = !(arg->allocation.heap_id_mask & mask);
>>
>>
>> validate_ioctl_arg() is really convoluted. From reading just the patch
>> I at first thought we were returning 1 on failure. Just say:
>>
>> if (!(arg->allocation.heap_id_mask & mask))
>> return -EINVAL;
>> return 0;
>>
>> If you want to fix the surrounding code in a separate patch that would
>> be good. It would be more clear to say:
>>
>> if (arg->query.reserved0 != 0 ||
>> arg->query.reserved1 != 0 ||
>> arg->query.reserved2 != 0)
>> return -EINVAL;
>
> I agree I will add a fix for that in next version
>
>>
>>> + break;
>>> default:
>>> break;
>>> }
>>> @@ -70,7 +75,7 @@ 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..5144f1a 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;
>>>
>>> @@ -541,11 +543,21 @@ void 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__);
>>>
>>
>> I don't think it can happen in current code but we should proabably have
>> a check here for:
>>
>> if (heap_id >= ION_DEV_MAX)
>> return -EBUSY;
>>
>> (It's possible I have missed something).
>>
>
> You are right I will add that
>
> Thanks
>>
>>> + 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;
>>> +
>>> spin_lock_init(&heap->free_lock);
>>> heap->free_list_size = 0;

What will happen to an application which looks for /dev/ion?

Thanks
Tomas

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