diff mbox series

[net-next,v5,1/7] tun: Refactor CONFIG_TUN_VNET_CROSS_LE

Message ID 20250205-tun-v5-1-15d0b32e87fa@daynix.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series tun: Unify vnet implementation | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: andrew+netdev@lunn.ch
netdev/build_clang success Errors and warnings before: 1 this patch: 1
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 52 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 1 now: 0
netdev/contest success net-next-2025-02-06--00-00 (tests: 891)

Commit Message

Akihiko Odaki Feb. 5, 2025, 6:22 a.m. UTC 
Check IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) to save some lines and make
future changes easier.

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

Comments

Willem de Bruijn Feb. 5, 2025, 9:06 p.m. UTC | #1 
Akihiko Odaki wrote:
> Check IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) to save some lines and make
> future changes easier.
> 
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> 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();
Akihiko Odaki Feb. 6, 2025, 6:53 a.m. UTC | #2 
On 2025/02/06 6:06, Willem de Bruijn wrote:
> Akihiko Odaki wrote:
>> Check IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) to save some lines and make
>> future changes easier.
>>
>> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
>> 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.
diff mbox series

Patch

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();
 }
 
@@ -309,6 +309,9 @@  static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
 {
 	int be = !!(tun->flags & TUN_VNET_BE);
 
+	if (!IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE))
+		return -EINVAL;
+
 	if (put_user(be, argp))
 		return -EFAULT;
 
@@ -319,6 +322,9 @@  static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 {
 	int be;
 
+	if (!IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE))
+		return -EINVAL;
+
 	if (get_user(be, argp))
 		return -EFAULT;
 
@@ -329,22 +335,6 @@  static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
 
 	return 0;
 }
-#else
-static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
-{
-	return virtio_legacy_is_little_endian();
-}
-
-static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
-{
-	return -EINVAL;
-}
-
-static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
-{
-	return -EINVAL;
-}
-#endif /* CONFIG_TUN_VNET_CROSS_LE */
 
 static inline bool tun_is_little_endian(struct tun_struct *tun)
 {