On 2025/02/06 6:06, Willem de Bruijn wrote:

Akihiko Odaki wrote:

quoted

Check IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) to save some lines and make
future changes easier.

Signed-off-by: Akihiko Odaki <redacted>
Reviewed-by: Willem de Bruijn <willemb@google.com>
---
  drivers/net/tun.c | 26 ++++++++------------------
  1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index e816aaba8e5f2ed06f8832f79553b6c976e75bb8..452fc5104260fe7ff5fdd5cedc5d2647cbe35c79 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c

@@ -298,10 +298,10 @@ static bool tun_napi_frags_enabled(const struct tun_file *tfile)
  	return tfile->napi_frags_enabled;
  }
  
-#ifdef CONFIG_TUN_VNET_CROSS_LE
  static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
  {
-	return tun->flags & TUN_VNET_BE ? false :
+	return !(IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) &&
+		 (tun->flags & TUN_VNET_BE)) &&
  		virtio_legacy_is_little_endian();

Since I have other comments to the series:

Can we make this a bit simpler to the reader, by splitting the test:

     if (IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) && tun->flags & TUN_VNET_BE)
             return false;

     return virtio_legacy_is_little_endian();

I kept all in one expression to show how different variables are reduced 
into one bool value, but I agree it is too complicated.

I'm adding a new variable to simplify this. The return statement will 
look like: return !be && virtio_legacy_is_little_endian();

It means: for tun, whether the legacy format is in little endian will be 
determined from the tun-specific big-endian flag and the virtio's common 
logic.