[EARLY RFC][PATCH 2/4] ion: Initial hack to create per heap devices
John Stultz
john.stultz at linaro.org
Fri Feb 15 20:24:10 UTC 2019
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.
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 */
--
2.7.4
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