[PATCHv3 2/2] staging: android: ion: Add ioctl to query available heaps

From: Laura Abbott
Date: Wed Sep 07 2016 - 14:50:19 EST



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>
---
v3: Include some refactoring that was previously part of the dropped ABI ioctl.
Use u64_to_user_ptr to avoid warnings and ugly double casts. General rebase
due to dropped ABI ioctl.
---
drivers/staging/android/ion/ion-ioctl.c | 53 ++++++++++++++++++++++++++-------
drivers/staging/android/ion/ion.c | 43 ++++++++++++++++++++++++++
drivers/staging/android/ion/ion_priv.h | 3 ++
drivers/staging/android/uapi/ion.h | 39 ++++++++++++++++++++++++
4 files changed, 128 insertions(+), 10 deletions(-)

diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
index 341ba7d..7e7431d 100644
--- a/drivers/staging/android/ion/ion-ioctl.c
+++ b/drivers/staging/android/ion/ion-ioctl.c
@@ -22,6 +22,31 @@
#include "ion_priv.h"
#include "compat_ion.h"

+union ion_ioctl_arg {
+ struct ion_fd_data fd;
+ struct ion_allocation_data allocation;
+ struct ion_handle_data handle;
+ struct ion_custom_data custom;
+ struct ion_heap_query query;
+};
+
+static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
+{
+ int ret = 0;
+
+ switch (cmd) {
+ case ION_IOC_HEAP_QUERY:
+ ret = arg->query.reserved0 != 0;
+ ret |= arg->query.reserved1 != 0;
+ ret |= arg->query.reserved2 != 0;
+ break;
+ default:
+ break;
+ }
+
+ return ret ? -EINVAL : 0;
+}
+
/* fix up the cases where the ioctl direction bits are incorrect */
static unsigned int ion_ioctl_dir(unsigned int cmd)
{
@@ -42,22 +67,27 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
struct ion_handle *cleanup_handle = NULL;
int ret = 0;
unsigned int dir;
-
- union {
- struct ion_fd_data fd;
- struct ion_allocation_data allocation;
- struct ion_handle_data handle;
- struct ion_custom_data custom;
- } data;
+ union ion_ioctl_arg data;

dir = ion_ioctl_dir(cmd);

if (_IOC_SIZE(cmd) > sizeof(data))
return -EINVAL;

- if (dir & _IOC_WRITE)
- if (copy_from_user(&data, (void __user *)arg, _IOC_SIZE(cmd)))
- return -EFAULT;
+ /*
+ * 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 (WARN_ON_ONCE(ret))
+ return ret;
+
+ if (!(dir & _IOC_WRITE))
+ memset(&data, 0, sizeof(data));

switch (cmd) {
case ION_IOC_ALLOC:
@@ -129,6 +159,9 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
data.custom.arg);
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 a92804f..396ded5 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -1159,6 +1159,48 @@ 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 = u64_to_user_ptr(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;
@@ -1376,6 +1418,7 @@ 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 4a78fab..3c3b324 100644
--- a/drivers/staging/android/ion/ion_priv.h
+++ b/drivers/staging/android/ion/ion_priv.h
@@ -102,6 +102,7 @@ struct ion_device {
struct dentry *debug_root;
struct dentry *heaps_debug_root;
struct dentry *clients_debug_root;
+ int heap_cnt;
};

/**
@@ -467,4 +468,6 @@ 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 a9c4e8b..647f130 100644
--- a/drivers/staging/android/uapi/ion.h
+++ b/drivers/staging/android/uapi/ion.h
@@ -128,6 +128,36 @@ struct ion_custom_data {
unsigned long arg;
};

+#define MAX_HEAP_NAME 32
+
+/**
+ * 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'

/**
@@ -194,4 +224,13 @@ struct ion_custom_data {
*/
#define ION_IOC_CUSTOM _IOWR(ION_IOC_MAGIC, 6, struct ion_custom_data)

+/**
+ * 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, 8, \
+ struct ion_heap_query)
+
#endif /* _UAPI_LINUX_ION_H */
--
2.7.4