2022-12-05 21:43:09

by Rasmus Villemoes

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Subject: [PATCH] net: fec: properly guard irq coalesce setup

Prior to the Fixes: commit, the initialization code went through the
same fec_enet_set_coalesce() function as used by ethtool, and that
function correctly checks whether the current variant has support for
irq coalescing.

Now that the initialization code instead calls fec_enet_itr_coal_set()
directly, that call needs to be guarded by a check for the
FEC_QUIRK_HAS_COALESCE bit.

Fixes: df727d4547de (net: fec: don't reset irq coalesce settings to defaults on "ip link up")
Reported-by: Greg Ungerer <[email protected]>
Signed-off-by: Rasmus Villemoes <[email protected]>
---
drivers/net/ethernet/freescale/fec_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 2ca2b61b451f..23e1a94b9ce4 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1220,7 +1220,8 @@ fec_restart(struct net_device *ndev)
writel(0, fep->hwp + FEC_IMASK);

/* Init the interrupt coalescing */
- fec_enet_itr_coal_set(ndev);
+ if (fep->quirks & FEC_QUIRK_HAS_COALESCE)
+ fec_enet_itr_coal_set(ndev);
}

static int fec_enet_ipc_handle_init(struct fec_enet_private *fep)
--
2.37.2


2022-12-06 06:45:26

by Alexander Stein

[permalink] [raw]
Subject: Re: [PATCH] net: fec: properly guard irq coalesce setup

Am Montag, 5. Dezember 2022, 21:46:04 CET schrieb Rasmus Villemoes:
> Prior to the Fixes: commit, the initialization code went through the
> same fec_enet_set_coalesce() function as used by ethtool, and that
> function correctly checks whether the current variant has support for
> irq coalescing.
>
> Now that the initialization code instead calls fec_enet_itr_coal_set()
> directly, that call needs to be guarded by a check for the
> FEC_QUIRK_HAS_COALESCE bit.
>
> Fixes: df727d4547de (net: fec: don't reset irq coalesce settings to defaults
> on "ip link up") Reported-by: Greg Ungerer <[email protected]>
> Signed-off-by: Rasmus Villemoes <[email protected]>
> ---
> drivers/net/ethernet/freescale/fec_main.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c index
> 2ca2b61b451f..23e1a94b9ce4 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -1220,7 +1220,8 @@ fec_restart(struct net_device *ndev)
> writel(0, fep->hwp + FEC_IMASK);
>
> /* Init the interrupt coalescing */
> - fec_enet_itr_coal_set(ndev);
> + if (fep->quirks & FEC_QUIRK_HAS_COALESCE)
> + fec_enet_itr_coal_set(ndev);
> }
>
> static int fec_enet_ipc_handle_init(struct fec_enet_private *fep)

I'm wondering if this check should be added to fec_enet_itr_coal_set()
instead. Right now any additional caller has to do it's own check for
FEC_QUIRK_HAS_COALESCE, so why not do check in fec_enet_itr_coal_set?
But I'm okay with this change as well.

Best regards,
Alexander


2022-12-06 09:44:30

by Rasmus Villemoes

[permalink] [raw]
Subject: Re: [PATCH] net: fec: properly guard irq coalesce setup

On 06/12/2022 07.16, Alexander Stein wrote:
> Am Montag, 5. Dezember 2022, 21:46:04 CET schrieb Rasmus Villemoes:
>> Prior to the Fixes: commit, the initialization code went through the
>> same fec_enet_set_coalesce() function as used by ethtool, and that
>> function correctly checks whether the current variant has support for
>> irq coalescing.
>>
>> Now that the initialization code instead calls fec_enet_itr_coal_set()
>> directly, that call needs to be guarded by a check for the
>> FEC_QUIRK_HAS_COALESCE bit.
>>
>> Fixes: df727d4547de (net: fec: don't reset irq coalesce settings to defaults
>> on "ip link up") Reported-by: Greg Ungerer <[email protected]>
>> Signed-off-by: Rasmus Villemoes <[email protected]>
>> ---
>> drivers/net/ethernet/freescale/fec_main.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/freescale/fec_main.c
>> b/drivers/net/ethernet/freescale/fec_main.c index
>> 2ca2b61b451f..23e1a94b9ce4 100644
>> --- a/drivers/net/ethernet/freescale/fec_main.c
>> +++ b/drivers/net/ethernet/freescale/fec_main.c
>> @@ -1220,7 +1220,8 @@ fec_restart(struct net_device *ndev)
>> writel(0, fep->hwp + FEC_IMASK);
>>
>> /* Init the interrupt coalescing */
>> - fec_enet_itr_coal_set(ndev);
>> + if (fep->quirks & FEC_QUIRK_HAS_COALESCE)
>> + fec_enet_itr_coal_set(ndev);
>> }
>>
>> static int fec_enet_ipc_handle_init(struct fec_enet_private *fep)
>
> I'm wondering if this check should be added to fec_enet_itr_coal_set()
> instead. Right now any additional caller has to do it's own check for
> FEC_QUIRK_HAS_COALESCE, so why not do check in fec_enet_itr_coal_set?

Yeah, I did consider that (see
https://lore.kernel.org/netdev/[email protected]/).
But in the end I decided against it, for various small reasons.
Primarily my thinking was that while this caller is obviously ok with
fec_enet_itr_coal_set() just silently being a no-op, it's not clear that
some future caller wouldn't have to check the bit themselves and return
-EOPNOTSUPP or some other error just like the ethtool method does. Of
course we could also make fec_enet_itr_coal_set() not return void, but
then it's a whole different refactoring and definitely not for post-rc8.

But also, the above was what I had sent out as a "something like this?"
and tested on my own hardware before heading home, and due to the
imminent release, I wanted to send out the patch ASAP.

Rasmus

2022-12-07 04:45:01

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH] net: fec: properly guard irq coalesce setup

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <[email protected]>:

On Mon, 5 Dec 2022 21:46:04 +0100 you wrote:
> Prior to the Fixes: commit, the initialization code went through the
> same fec_enet_set_coalesce() function as used by ethtool, and that
> function correctly checks whether the current variant has support for
> irq coalescing.
>
> Now that the initialization code instead calls fec_enet_itr_coal_set()
> directly, that call needs to be guarded by a check for the
> FEC_QUIRK_HAS_COALESCE bit.
>
> [...]

Here is the summary with links:
- net: fec: properly guard irq coalesce setup
https://git.kernel.org/netdev/net/c/7e6303567ce3

You are awesome, thank you!
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