Re: [PATCH] vhost: fix VHOST_GET_BACKEND_FEATURES ioctl request definition

On Tue, Sep 04, 2018 at 11:08:40AM +0800, Jason Wang wrote:

On 2018年09月04日 10:22, Michael S. Tsirkin wrote:

quoted

On Mon, Sep 03, 2018 at 08:59:13PM +0300, Gleb Fotengauer-Malinovskiy wrote:

quoted

The _IOC_READ flag fits this ioctl request more because this request
actually only writes to, but doesn't read from userspace.
See NOTEs in include/uapi/asm-generic/ioctl.h for more information.

Fixes: 429711aec282 ("vhost: switch to use new message format")
Signed-off-by: Gleb Fotengauer-Malinovskiy <redacted>

Hmm it does make sense, and it's not too late to fix this up.
Jason, what's your take on this? Was _IOW intentional?

My bad, not intentional. And I agree that fixing this is not too late.

So

Acked-by: Jason Wang <redacted>

OK then

Acked-by: Michael S. Tsirkin <mst@redhat.com>

quoted

quoted

---
  include/uapi/linux/vhost.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index b1e22c40c4b6..84c3de89696a 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h

@@ -176,7 +176,7 @@ struct vhost_memory {
  #define VHOST_BACKEND_F_IOTLB_MSG_V2 0x1
  #define VHOST_SET_BACKEND_FEATURES _IOW(VHOST_VIRTIO, 0x25, __u64)
-#define VHOST_GET_BACKEND_FEATURES _IOW(VHOST_VIRTIO, 0x26, __u64)
+#define VHOST_GET_BACKEND_FEATURES _IOR(VHOST_VIRTIO, 0x26, __u64)
  /* VHOST_NET specific defines */

-- 
glebfm