staging: android: ion: Add ioctl to query available heaps

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@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
index 341ba7d..7e7431d 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 */