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SubjectRe: [PATCH] staging: ion: create one device entry per heap
On Tue, Sep 19, 2017 at 12:20:15PM +0200, Benjamin Gaignard wrote:
> 2017-09-19 12:15 GMT+02:00 Tomas Winkler <tomasw@gmail.com>:
> > 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?
>
> /dev/ion will no more exist with this patch.
> Since ion ABI have already change a lot I don't think that could
> be a problem to change also ion device.

So, what did you just break in userspace? :(

Do you also have userspace patches submitted anywhere to handle this
change?

thanks,

greg k-h

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