[PATCH] vduse: return compat ioctl results directly

[Linfeng Sun]

The compat handler handles VDUSE_IOTLB_GET_FD and VDUSE_VQ_GET_INFO, but
then calls the native handler. Their different command sizes make native
dispatch return -ENOIOCTLCMD.

For GET_FD, this overwrites receive_fd()'s return value after the
descriptor is installed, leaking one fd per call. Return handled compat
results directly and use native dispatch only for other commands.

Fixes: 455a2a1af926 ("vduse: fix compat handling for VDUSE_IOTLB_GET_FD/VDUSE_VQ_GET_INFO")
Signed-off-by: Linfeng Sun <linfeng.sun.dev@xxxxxxxxx>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 4dea4d6a3855..49a231bdf948 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1882,11 +1882,11 @@ static long vduse_dev_compat_ioctl(struct file *file, unsigned int cmd,
 		break;
 	}
 	default:
-		ret = -ENOIOCTLCMD;
-		break;
+		return vduse_dev_ioctl(file, cmd,
+				       (unsigned long)compat_ptr(arg));
 	}
 
-	return vduse_dev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+	return ret;
 }
 #else
 #define vduse_dev_compat_ioctl compat_ptr_ioctl

---
base-commit: d7808b37da0a619cf1fa541c2384e783fecc2480

Best regards,
-- 
Linfeng Sun <linfeng.sun.dev@xxxxxxxxx>