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SubjectRe: [PATCH] staging: ion: create one device entry per heap
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;

> + 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).


> + 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;
>

regards,
dan carpenter


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