Re: [PATCH 1/2] staging: binder: add __user annotation in binder.c

[Joe Perches <joe@perches.com>]

On Tue, 2014-03-25 at 01:24 +0100, Mathieu Maret wrote:
> Fix the following spare warning

sparse

> drivers/staging/android/binder.c:2691:21: warning: incorrect type in argument 1 (different address spaces)
[]
> diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c
[]
> @@ -2688,7 +2688,7 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
[]
> -		if (put_user(BINDER_CURRENT_PROTOCOL_VERSION, &((struct binder_version *)ubuf)->protocol_version)) {
> +		if (put_user(BINDER_CURRENT_PROTOCOL_VERSION, &((struct binder_version __user *)ubuf)->protocol_version)) {

That's certainly one way to do it, but I'd suggest
using a temporary instead

 drivers/staging/android/binder.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c
index cfe4bc8..1f5e249 100644
--- a/drivers/staging/android/binder.c
+++ b/drivers/staging/android/binder.c
@@ -2683,16 +2683,20 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		binder_free_thread(proc, thread);
 		thread = NULL;
 		break;
-	case BINDER_VERSION:
+	case BINDER_VERSION: {
+		struct binder_version __user *ver = ubuf;
+
 		if (size != sizeof(struct binder_version)) {
 			ret = -EINVAL;
 			goto err;
 		}
-		if (put_user(BINDER_CURRENT_PROTOCOL_VERSION, &((struct binder_version *)ubuf)->protocol_version)) {
+		if (put_user(BINDER_CURRENT_PROTOCOL_VERSION,
+			     &ver->protocol_version)) {
 			ret = -EINVAL;
 			goto err;
 		}
 		break;
+	}
 	default:
 		ret = -EINVAL;
 		goto err;