[EARLY RFC][PATCH 2/4] ion: Initial hack to create per heap devices
Laura Abbott
labbott at redhat.com
Tue Feb 19 21:17:28 UTC 2019
On 2/15/19 12:24 PM, John Stultz wrote:
> One of the issues w/ the /dev/ion interface is that we have to
> provide the complexity of a heap query interface and we end up
> multiplexing all the heap access through that one interface via
> a bit mask (which currently limits the heaps to 32).
>
> There has been a long running todo to provide per-heap devices
> which would make the heap discovery/query interface "ls", and
> would allow for different heaps to have different permisisons
> and sepolicy rules.
>
> TODOs:
> * Android doesn't use udev so "ion_heaps/%s" names don't
> automatically create a /dev/ subdir. I need to rework
> from miscdev to creating a proper device class and add
> a "subsystem" entry for the DeviceHandler to match with
>
> * Each CMA region is exposed via a separate heap, not sure
> if this is desired or not, and we may need to improve the
> naming.
>
Every CMA region getting exposed was a side effect of doing
the eneumeration without tying it to devicetree or other firmware.
I'm not opposed to limiting the heaps exposed if we can find
a good way to do so that's still compliant with devicetree/whatever.
Thanks,
Laura
> Cc: Laura Abbott <labbott at redhat.com>
> Cc: Sumit Semwal <sumit.semwal at linaro.org>
> Cc: Liam Mark <lmark at codeaurora.org>
> Cc: Brian Starkey <Brian.Starkey at arm.com>
> Cc: Andrew F. Davis <afd at ti.com>
> Cc: Alistair Strachan <astrachan at google.com>
> Cc: dri-devel at lists.freedesktop.org
> Signed-off-by: John Stultz <john.stultz at linaro.org>
> ---
> drivers/staging/android/ion/ion-ioctl.c | 62 +++++++++++++++++++++++++++++++++
> drivers/staging/android/ion/ion.c | 18 ++++++++++
> drivers/staging/android/ion/ion.h | 2 ++
> drivers/staging/android/uapi/ion.h | 28 +++++++++++++++
> 4 files changed, 110 insertions(+)
>
> diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
> index 458a9f2..ea8d263 100644
> --- a/drivers/staging/android/ion/ion-ioctl.c
> +++ b/drivers/staging/android/ion/ion-ioctl.c
> @@ -12,6 +12,7 @@
>
> union ion_ioctl_arg {
> struct ion_allocation_data allocation;
> + struct ion_heap_allocation_data heap_allocation;
> struct ion_heap_query query;
> u32 version;
> };
> @@ -100,3 +101,64 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> }
> return ret;
> }
> +
> +long ion_heap_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> +{
> + int ret = 0;
> + unsigned int dir;
> + union ion_ioctl_arg data;
> +
> + dir = ion_ioctl_dir(cmd);
> +
> + if (_IOC_SIZE(cmd) > sizeof(data))
> + return -EINVAL;
> +
> + /*
> + * The copy_from_user is unconditional here for both read and write
> + * to do the validate. If there is no write for the ioctl, the
> + * buffer is cleared
> + */
> + if (copy_from_user(&data, (void __user *)arg, _IOC_SIZE(cmd)))
> + return -EFAULT;
> +
> + ret = validate_ioctl_arg(cmd, &data);
> + if (ret) {
> + pr_warn_once("%s: ioctl validate failed\n", __func__);
> + return ret;
> + }
> +
> + if (!(dir & _IOC_WRITE))
> + memset(&data, 0, sizeof(data));
> +
> + switch (cmd) {
> + case ION_IOC_HEAP_ALLOC:
> + {
> + struct miscdevice *miscdev = filp->private_data;
> + struct ion_heap *heap;
> + int fd;
> +
> + heap = container_of(miscdev, struct ion_heap, heap_dev);
> +
> + fd = ion_alloc(data.heap_allocation.len,
> + (1 << heap->id),
> + data.heap_allocation.flags);
> + if (fd < 0)
> + return fd;
> +
> + data.heap_allocation.fd = fd;
> +
> + break;
> + }
> + case ION_IOC_VERSION:
> + data.version = ION_VERSION;
> + break;
> + default:
> + return -ENOTTY;
> + }
> +
> + if (dir & _IOC_READ) {
> + if (copy_to_user((void __user *)arg, &data, _IOC_SIZE(cmd)))
> + return -EFAULT;
> + }
> + return ret;
> +}
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index 6f5afab..1f7c893 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -492,6 +492,14 @@ int ion_query_heaps(struct ion_heap_query *query)
> return ret;
> }
>
> +static const struct file_operations ion_heap_fops = {
> + .owner = THIS_MODULE,
> + .unlocked_ioctl = ion_heap_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = ion_heap_ioctl,
> +#endif
> +};
> +
> static const struct file_operations ion_fops = {
> .owner = THIS_MODULE,
> .unlocked_ioctl = ion_ioctl,
> @@ -540,12 +548,22 @@ void ion_device_add_heap(struct ion_heap *heap)
> struct ion_device *dev = internal_dev;
> int ret;
> struct dentry *heap_root;
> + char *heap_name;
> char debug_name[64];
>
> if (!heap->ops->allocate || !heap->ops->free)
> pr_err("%s: can not add heap with invalid ops struct.\n",
> __func__);
>
> + heap_name = kasprintf(GFP_KERNEL, "ion_heaps/%s", heap->name);
> + heap->heap_dev.name = heap_name;
> + heap->heap_dev.minor = MISC_DYNAMIC_MINOR;
> + heap->heap_dev.fops = &ion_heap_fops;
> + heap->heap_dev.parent = NULL;
> + ret = misc_register(&heap->heap_dev);
> + if (ret)
> + pr_err("ion: failed to register misc device.\n");
> +
> spin_lock_init(&heap->free_lock);
> spin_lock_init(&heap->stat_lock);
> heap->free_list_size = 0;
> diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
> index 439e682..7ed4a6a 100644
> --- a/drivers/staging/android/ion/ion.h
> +++ b/drivers/staging/android/ion/ion.h
> @@ -170,6 +170,7 @@ struct ion_heap_ops {
> */
> struct ion_heap {
> struct plist_node node;
> + struct miscdevice heap_dev;
> struct ion_device *dev;
> enum ion_heap_type type;
> struct ion_heap_ops *ops;
> @@ -333,6 +334,7 @@ int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
> int nr_to_scan);
>
> long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
> +long ion_heap_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
>
> int ion_query_heaps(struct ion_heap_query *query);
>
> diff --git a/drivers/staging/android/uapi/ion.h b/drivers/staging/android/uapi/ion.h
> index c480448..20db09f 100644
> --- a/drivers/staging/android/uapi/ion.h
> +++ b/drivers/staging/android/uapi/ion.h
> @@ -57,6 +57,25 @@ enum ion_heap_type {
> */
>
> /**
> + * struct ion_heap_allocation_data - metadata passed from userspace for
> + * allocations
> + * @len: size of the allocation
> + * @heap_id_mask: mask of heap ids to allocate from
> + * @flags: flags passed to heap
> + * @handle: pointer that will be populated with a cookie to use to
> + * refer to this allocation
> + *
> + * Provided by userspace as an argument to the ioctl
> + */
> +struct ion_heap_allocation_data {
> + __u64 len;
> + __u32 flags;
> + __u32 fd;
> + __u32 reserved0;
> + __u32 reserved1;
> +};
> +
> +/**
> * struct ion_allocation_data - metadata passed from userspace for allocations
> * @len: size of the allocation
> * @heap_id_mask: mask of heap ids to allocate from
> @@ -131,4 +150,13 @@ struct ion_heap_query {
> */
> #define ION_IOC_VERSION _IOR(ION_IOC_MAGIC, 9, u32)
>
> +/**
> + * DOC: ION_IOC_HEAP_ALLOC - allocate memory from heap
> + *
> + * Takes an ion_heap_allocation_data struct and returns it with the handle field
> + * populated with the opaque handle for the allocation.
> + */
> +#define ION_IOC_HEAP_ALLOC _IOWR(ION_IOC_MAGIC, 10, \
> + struct ion_heap_allocation_data)
> +
> #endif /* _UAPI_LINUX_ION_H */
>
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