diff mbox series

[net,v2,1/6] igc: Rename qbv_enable to taprio_offload_enable

Message ID 20230619100858.116286-2-florian.kauer@linutronix.de
State New
Headers
Series igc: Fix corner cases for TSN offload |

Commit Message

Florian Kauer June 19, 2023, 10:08 a.m. UTC 
  In the current implementation the flags adapter->qbv_enable
and IGC_FLAG_TSN_QBV_ENABLED have a similar name, but do not
have the same meaning. The first one is used only to indicate
taprio offload (i.e. when igc_save_qbv_schedule was called),
while the second one corresponds to the Qbv mode of the hardware.
However, the second one is also used to support the TX launchtime
feature, i.e. ETF qdisc offload. This leads to situations where
adapter->qbv_enable is false, but the flag IGC_FLAG_TSN_QBV_ENABLED
is set. This is prone to confusion.

The rename should reduce this confusion. Since it is a pure
rename, it has no impact on functionality.

Fixes: e17090eb2494 ("igc: allow BaseTime 0 enrollment for Qbv")
Signed-off-by: Florian Kauer <florian.kauer@linutronix.de>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
---
 drivers/net/ethernet/intel/igc/igc.h      | 2 +-
 drivers/net/ethernet/intel/igc/igc_main.c | 2 +-
 drivers/net/ethernet/intel/igc/igc_tsn.c  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

Comments

naamax.meir July 2, 2023, 1:42 p.m. UTC | #1 
On 6/19/2023 13:08, Florian Kauer wrote:
> In the current implementation the flags adapter->qbv_enable
> and IGC_FLAG_TSN_QBV_ENABLED have a similar name, but do not
> have the same meaning. The first one is used only to indicate
> taprio offload (i.e. when igc_save_qbv_schedule was called),
> while the second one corresponds to the Qbv mode of the hardware.
> However, the second one is also used to support the TX launchtime
> feature, i.e. ETF qdisc offload. This leads to situations where
> adapter->qbv_enable is false, but the flag IGC_FLAG_TSN_QBV_ENABLED
> is set. This is prone to confusion.
> 
> The rename should reduce this confusion. Since it is a pure
> rename, it has no impact on functionality.
> 
> Fixes: e17090eb2494 ("igc: allow BaseTime 0 enrollment for Qbv")
> Signed-off-by: Florian Kauer <florian.kauer@linutronix.de>
> Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
> ---
>   drivers/net/ethernet/intel/igc/igc.h      | 2 +-
>   drivers/net/ethernet/intel/igc/igc_main.c | 2 +-
>   drivers/net/ethernet/intel/igc/igc_tsn.c  | 2 +-
>   3 files changed, 3 insertions(+), 3 deletions(-)

Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Florian Kauer July 2, 2023, 7:17 p.m. UTC | #2 
Hi Markus,

On 02.07.23 18:55, Markus Elfring wrote:
>> The rename should reduce this confusion.
> 
> Would the wording “Reduce this confusion by renaming a variable at three places”
> be more appropriate for a subsequent change description?
> 
> See also:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.4#n94

Thanks for pointing that out (also in your other mail for this series).
I will be more careful regarding the use of imperative mood.

> 
>>                                          Since it is a pure
>> rename, it has no impact on functionality.
>>
>> Fixes: e17090eb2494 ("igc: allow BaseTime 0 enrollment for Qbv")
> 
> How does such information fit together?

The referenced commit introduced an issue into the kernel by
introducing a variable that does not exactly describe its actual purpose.
It is not only a cosmetic change, but in my view this confusion
was related to other issues (see the other patches). So, it seemed to be worth
fixing alongside with the other fixes, even if it does not directly impact
functionality if it is applied or not (until someone else comes along,
also gets confused and introduces another bug...).

Thanks,
Florian
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
index 34aebf00a512..4c7a1e92ce4c 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -185,7 +185,7 @@  struct igc_adapter {
 
 	ktime_t base_time;
 	ktime_t cycle_time;
-	bool qbv_enable;
+	bool taprio_offload_enable;
 	u32 qbv_config_change_errors;
 
 	/* OS defined structs */
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index fa764190f270..dda057a3b5e3 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -6075,7 +6075,7 @@  static int igc_save_qbv_schedule(struct igc_adapter *adapter,
 	size_t n;
 	int i;
 
-	adapter->qbv_enable = qopt->enable;
+	adapter->taprio_offload_enable = qopt->enable;
 
 	if (!qopt->enable)
 		return igc_tsn_clear_schedule(adapter);
diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
index 94a2b0dfb54d..c6636a7264d5 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -37,7 +37,7 @@  static unsigned int igc_tsn_new_flags(struct igc_adapter *adapter)
 {
 	unsigned int new_flags = adapter->flags & ~IGC_FLAG_TSN_ANY_ENABLED;
 
-	if (adapter->qbv_enable)
+	if (adapter->taprio_offload_enable)
 		new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
 
 	if (is_any_launchtime(adapter))