[PATCHv2 4/4] staging: android: ion: Add ioctl to query available heaps

[Laura Abbott]

Ion clients currently lack a good method to determine what
heaps are available and what ids they map to. This leads
to tight coupling between user and kernel space and headaches.
Add a query ioctl to let userspace know the availability of
heaps.

Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
---
 drivers/staging/android/ion/ion-ioctl.c | 11 +++++++++
 drivers/staging/android/ion/ion.c       | 44 +++++++++++++++++++++++++++++++++
 drivers/staging/android/ion/ion_priv.h  |  3 +++
 drivers/staging/android/uapi/ion.h      | 39 +++++++++++++++++++++++++++++
 4 files changed, 97 insertions(+)

diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
index 53b9520..e76d517 100644
--- a/drivers/staging/android/ion/ion-ioctl.c
+++ b/drivers/staging/android/ion/ion-ioctl.c
@@ -28,6 +28,7 @@ union ion_ioctl_arg {
 	struct ion_handle_data handle;
 	struct ion_custom_data custom;
 	struct ion_abi_version abi_version;
+	struct ion_heap_query query;
 };
 
 static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
@@ -38,6 +39,11 @@ static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
 	case ION_IOC_ABI_VERSION:
 		ret = arg->abi_version.reserved != 0;
 		break;
+	case ION_IOC_HEAP_QUERY:
+		ret = arg->query.reserved0 != 0;
+		ret |= arg->query.reserved1 != 0;
+		ret |= arg->query.reserved2 != 0;
+		break;
 	default:
 		break;
 	}
@@ -162,6 +168,11 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		data.abi_version.abi_version = ION_ABI_VERSION;
 		break;
 	}
+	case ION_IOC_HEAP_QUERY:
+	{
+		ret = ion_query_heaps(client, &data.query);
+		break;
+	}
 	default:
 		return -ENOTTY;
 	}
diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 975b48f..91b765c 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -1174,6 +1174,49 @@ int ion_sync_for_device(struct ion_client *client, int fd)
 	return 0;
 }
 
+int ion_query_heaps(struct ion_client *client, struct ion_heap_query *query)
+{
+	struct ion_device *dev = client->dev;
+	struct ion_heap_data __user *buffer =
+		(struct ion_heap_data __user *)query->heaps;
+	int ret = -EINVAL, cnt = 0, max_cnt;
+	struct ion_heap *heap;
+	struct ion_heap_data hdata;
+
+	memset(&hdata, 0, sizeof(hdata));
+
+	down_read(&dev->lock);
+	if (!buffer) {
+		query->cnt = dev->heap_cnt;
+		ret = 0;
+		goto out;
+	}
+
+	if (query->cnt <= 0)
+		goto out;
+
+	max_cnt = query->cnt;
+
+	plist_for_each_entry(heap, &dev->heaps, node) {
+		strncpy(hdata.name, heap->name, MAX_HEAP_NAME);
+		hdata.name[sizeof(hdata.name) - 1] = '\0';
+		hdata.type = heap->type;
+		hdata.heap_id = heap->id;
+
+		ret = copy_to_user(&buffer[cnt],
+				   &hdata, sizeof(hdata));
+
+		cnt++;
+		if (cnt >= max_cnt)
+			break;
+	}
+
+	query->cnt = cnt;
+out:
+	up_read(&dev->lock);
+	return ret;
+}
+
 static int ion_release(struct inode *inode, struct file *file)
 {
 	struct ion_client *client = file->private_data;
@@ -1391,6 +1434,7 @@ void ion_device_add_heap(struct ion_device *dev, struct ion_heap *heap)
 		}
 	}
 
+	dev->heap_cnt++;
 	up_write(&dev->lock);
 }
 EXPORT_SYMBOL(ion_device_add_heap);
diff --git a/drivers/staging/android/ion/ion_priv.h b/drivers/staging/android/ion/ion_priv.h
index 95df6a9..0d0c0aa 100644
--- a/drivers/staging/android/ion/ion_priv.h
+++ b/drivers/staging/android/ion/ion_priv.h
@@ -104,6 +104,7 @@ struct ion_device {
 	struct dentry *debug_root;
 	struct dentry *heaps_debug_root;
 	struct dentry *clients_debug_root;
+	int heap_cnt;
 };
 
 /**
@@ -469,4 +470,6 @@ struct ion_handle *ion_handle_get_by_id(struct ion_client *client,
 
 int ion_handle_put(struct ion_handle *handle);
 
+int ion_query_heaps(struct ion_client *client, struct ion_heap_query *query);
+
 #endif /* _ION_PRIV_H */
diff --git a/drivers/staging/android/uapi/ion.h b/drivers/staging/android/uapi/ion.h
index 7ca4e8b..112f257 100644
--- a/drivers/staging/android/uapi/ion.h
+++ b/drivers/staging/android/uapi/ion.h
@@ -137,11 +137,41 @@ struct ion_custom_data {
 
 #define ION_ABI_VERSION                KERNEL_VERSION(0, 1, 0)
 
+#define MAX_HEAP_NAME			32
+
 struct ion_abi_version {
 	__u32 abi_version;
 	__u32 reserved;
 };
 
+/**
+ * struct ion_heap_data - data about a heap
+ * @name - first 32 characters of the heap name
+ * @type - heap type
+ * @heap_id - heap id for the heap
+ */
+struct ion_heap_data {
+	char name[MAX_HEAP_NAME];
+	__u32 type;
+	__u32 heap_id;
+	__u32 reserved0;
+	__u32 reserved1;
+	__u32 reserved2;
+};
+
+/**
+ * struct ion_heap_query - collection of data about all heaps
+ * @cnt - total number of heaps to be copied
+ * @heaps - buffer to copy heap data
+ */
+struct ion_heap_query {
+	__u32 cnt; /* Total number of heaps to be copied */
+	__u32 reserved0; /* align to 64bits */
+	__u64 heaps; /* buffer to be populated */
+	__u32 reserved1;
+	__u32 reserved2;
+};
+
 #define ION_IOC_MAGIC		'I'
 
 /**
@@ -216,4 +246,13 @@ struct ion_abi_version {
 #define ION_IOC_ABI_VERSION    _IOR(ION_IOC_MAGIC, 8, \
 					struct ion_abi_version)
 
+/**
+ * DOC: ION_IOC_HEAP_QUERY - information about available heaps
+ *
+ * Takes an ion_heap_query structure and populates information about
+ * available Ion heaps.
+ */
+#define ION_IOC_HEAP_QUERY     _IOWR(ION_IOC_MAGIC, 12, \
+					struct ion_heap_query)
+
 #endif /* _UAPI_LINUX_ION_H */
-- 
2.7.4