[PATCH net v3 0/2] fix ti-am65-cpsw-nuss module removal

[PATCH net v3 0/2] fix ti-am65-cpsw-nuss module removal

[Nicolas Pitre]

Fix issues preventing rmmod of ti-am65-cpsw-nuss from working properly.

v3:

  - more patch submission minutiae

v2: https://lore.kernel.org/netdev/20241003172105.2712027-2-nico@fluxnic.net/T/

  - conform to netdev patch submission customs
  - address patch review trivias

v1: https://lore.kernel.org/netdev/20240927025301.1312590-2-nico@fluxnic.net/T/

[PATCH net v3 1/2] net: ethernet: ti: am65-cpsw: prevent WARN_ON upon module removal

[Nicolas Pitre]

From: Nicolas Pitre <npitre@baylibre.com>

In am65_cpsw_nuss_remove(), move the call to am65_cpsw_unregister_devlink()
after am65_cpsw_nuss_cleanup_ndev() to avoid triggering the
WARN_ON(devlink_port->type != DEVLINK_PORT_TYPE_NOTSET) in
devl_port_unregister(). Makes it coherent with usage in
m65_cpsw_nuss_register_ndevs()'s cleanup path.

Fixes: 58356eb31d60 ("net: ti: am65-cpsw-nuss: Add devlink support")
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index cbe99017cb..f6bc8a4dc6 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -3652,13 +3652,13 @@ static void am65_cpsw_nuss_remove(struct platform_device *pdev)
 		return;
 	}
 
-	am65_cpsw_unregister_devlink(common);
 	am65_cpsw_unregister_notifiers(common);
 
 	/* must unregister ndevs here because DD release_driver routine calls
 	 * dma_deconfigure(dev) before devres_release_all(dev)
 	 */
 	am65_cpsw_nuss_cleanup_ndev(common);
+	am65_cpsw_unregister_devlink(common);
 	am65_cpsw_nuss_phylink_cleanup(common);
 	am65_cpts_release(common->cpts);
 	am65_cpsw_disable_serdes_phy(common);
-- 
2.46.1

Re: [PATCH net v3 1/2] net: ethernet: ti: am65-cpsw: prevent WARN_ON upon module removal

[Roger Quadros]

On 04/10/2024 07:10, Nicolas Pitre wrote:
> From: Nicolas Pitre <npitre@baylibre.com>
> 
> In am65_cpsw_nuss_remove(), move the call to am65_cpsw_unregister_devlink()
> after am65_cpsw_nuss_cleanup_ndev() to avoid triggering the
> WARN_ON(devlink_port->type != DEVLINK_PORT_TYPE_NOTSET) in
> devl_port_unregister(). Makes it coherent with usage in
> m65_cpsw_nuss_register_ndevs()'s cleanup path.
> 
> Fixes: 58356eb31d60 ("net: ti: am65-cpsw-nuss: Add devlink support")
> Signed-off-by: Nicolas Pitre <npitre@baylibre.com>

Reviewed-by: Roger Quadros <rogerq@kernel.org>

[PATCH net v3 2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

[Nicolas Pitre]

From: Nicolas Pitre <npitre@baylibre.com>

Usage of devm_alloc_etherdev_mqs() conflicts with
am65_cpsw_nuss_cleanup_ndev() as the same struct net_device instances
get unregistered twice. Switch to alloc_etherdev_mqs() and make sure
am65_cpsw_nuss_cleanup_ndev() unregisters and frees those net_device
instances properly.

With this, it is finally possible to rmmod the driver without oopsing
the kernel.

Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver")
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index f6bc8a4dc6..e95457c988 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -2744,10 +2744,9 @@ am65_cpsw_nuss_init_port_ndev(struct am65_cpsw_common *common, u32 port_idx)
 		return 0;
 
 	/* alloc netdev */
-	port->ndev = devm_alloc_etherdev_mqs(common->dev,
-					     sizeof(struct am65_cpsw_ndev_priv),
-					     AM65_CPSW_MAX_QUEUES,
-					     AM65_CPSW_MAX_QUEUES);
+	port->ndev = alloc_etherdev_mqs(sizeof(struct am65_cpsw_ndev_priv),
+					AM65_CPSW_MAX_QUEUES,
+					AM65_CPSW_MAX_QUEUES);
 	if (!port->ndev) {
 		dev_err(dev, "error allocating slave net_device %u\n",
 			port->port_id);
@@ -2868,8 +2867,12 @@ static void am65_cpsw_nuss_cleanup_ndev(struct am65_cpsw_common *common)
 
 	for (i = 0; i < common->port_num; i++) {
 		port = &common->ports[i];
-		if (port->ndev && port->ndev->reg_state == NETREG_REGISTERED)
+		if (!port->ndev)
+			continue;
+		if (port->ndev->reg_state == NETREG_REGISTERED)
 			unregister_netdev(port->ndev);
+		free_netdev(port->ndev);
+		port->ndev = NULL;
 	}
 }
 
@@ -3613,16 +3616,17 @@ static int am65_cpsw_nuss_probe(struct platform_device *pdev)
 
 	ret = am65_cpsw_nuss_init_ndevs(common);
 	if (ret)
-		goto err_free_phylink;
+		goto err_ndevs_clear;
 
 	ret = am65_cpsw_nuss_register_ndevs(common);
 	if (ret)
-		goto err_free_phylink;
+		goto err_ndevs_clear;
 
 	pm_runtime_put(dev);
 	return 0;
 
-err_free_phylink:
+err_ndevs_clear:
+	am65_cpsw_nuss_cleanup_ndev(common);
 	am65_cpsw_nuss_phylink_cleanup(common);
 	am65_cpts_release(common->cpts);
 err_of_clear:
-- 
2.46.1

Re: [PATCH net v3 2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

[Roger Quadros]

Hi Nicolas,

On 04/10/2024 07:10, Nicolas Pitre wrote:
> From: Nicolas Pitre <npitre@baylibre.com>
> 
> Usage of devm_alloc_etherdev_mqs() conflicts with
> am65_cpsw_nuss_cleanup_ndev() as the same struct net_device instances
> get unregistered twice. Switch to alloc_etherdev_mqs() and make sure

Do we know why the same net device gets unregistered twice?

> am65_cpsw_nuss_cleanup_ndev() unregisters and frees those net_device
> instances properly.
> 
> With this, it is finally possible to rmmod the driver without oopsing
> the kernel.
> 
> Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver")
> Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
> ---
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 20 ++++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> index f6bc8a4dc6..e95457c988 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> @@ -2744,10 +2744,9 @@ am65_cpsw_nuss_init_port_ndev(struct am65_cpsw_common *common, u32 port_idx)
>  		return 0;
>  
>  	/* alloc netdev */
> -	port->ndev = devm_alloc_etherdev_mqs(common->dev,
> -					     sizeof(struct am65_cpsw_ndev_priv),
> -					     AM65_CPSW_MAX_QUEUES,
> -					     AM65_CPSW_MAX_QUEUES);
> +	port->ndev = alloc_etherdev_mqs(sizeof(struct am65_cpsw_ndev_priv),
> +					AM65_CPSW_MAX_QUEUES,
> +					AM65_CPSW_MAX_QUEUES);

Can we solve this issue without doing this change as
there are many error cases relying on devm managed freeing of netdev.


>  	if (!port->ndev) {
>  		dev_err(dev, "error allocating slave net_device %u\n",
>  			port->port_id);
> @@ -2868,8 +2867,12 @@ static void am65_cpsw_nuss_cleanup_ndev(struct am65_cpsw_common *common)
>  
>  	for (i = 0; i < common->port_num; i++) {
>  		port = &common->ports[i];
> -		if (port->ndev && port->ndev->reg_state == NETREG_REGISTERED)
> +		if (!port->ndev)
> +			continue;
> +		if (port->ndev->reg_state == NETREG_REGISTERED)
>  			unregister_netdev(port->ndev);
> +		free_netdev(port->ndev);
> +		port->ndev = NULL;

I still can't see what we are doing wrong in existing code.

>  	}
>  }
>  
> @@ -3613,16 +3616,17 @@ static int am65_cpsw_nuss_probe(struct platform_device *pdev)
>  
>  	ret = am65_cpsw_nuss_init_ndevs(common);
>  	if (ret)
> -		goto err_free_phylink;
> +		goto err_ndevs_clear;
>  
>  	ret = am65_cpsw_nuss_register_ndevs(common);
>  	if (ret)
> -		goto err_free_phylink;
> +		goto err_ndevs_clear;
>  
>  	pm_runtime_put(dev);
>  	return 0;
>  
> -err_free_phylink:
> +err_ndevs_clear:
> +	am65_cpsw_nuss_cleanup_ndev(common);
>  	am65_cpsw_nuss_phylink_cleanup(common);
>  	am65_cpts_release(common->cpts);
>  err_of_clear:

-- 
cheers,
-roger

Re: [PATCH net v3 2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

[Roger Quadros]

Hi Nicolas,

On 04/10/2024 12:09, Roger Quadros wrote:
> Hi Nicolas,
> 
> On 04/10/2024 07:10, Nicolas Pitre wrote:
>> From: Nicolas Pitre <npitre@baylibre.com>
>>
>> Usage of devm_alloc_etherdev_mqs() conflicts with
>> am65_cpsw_nuss_cleanup_ndev() as the same struct net_device instances
>> get unregistered twice. Switch to alloc_etherdev_mqs() and make sure
> 
> Do we know why the same net device gets unregistered twice?

On some boards there are 2 net devices per CPSW. so those those 2
getting unregistered?

On some investigation I found that the issue has to do with napi_list.
I don't exactly know why but it oopes in free_netdev() at napi_list
iterations
        list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
                netif_napi_del(p);

If we cleanup the napi list at remove then I don't see the oops anymore.

> 
>> am65_cpsw_nuss_cleanup_ndev() unregisters and frees those net_device
>> instances properly.
>>
>> With this, it is finally possible to rmmod the driver without oopsing
>> the kernel.
>>
>> Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver")
>> Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
>> ---

Can you please try the below patch instead?

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index f6bc8a4dc687..e214547aeba7 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -2206,14 +2206,11 @@ static void am65_cpsw_nuss_free_tx_chns(void *data)
 	}
 }
 
-static void am65_cpsw_nuss_remove_tx_chns(struct am65_cpsw_common *common)
+static void am65_cpsw_nuss_cleanup_tx_napi(struct am65_cpsw_common *common)
 {
 	struct device *dev = common->dev;
 	int i;
 
-	devm_remove_action(dev, am65_cpsw_nuss_free_tx_chns, common);
-
-	common->tx_ch_rate_msk = 0;
 	for (i = 0; i < common->tx_ch_num; i++) {
 		struct am65_cpsw_tx_chn *tx_chn = &common->tx_chns[i];
 
@@ -2222,7 +2219,15 @@ static void am65_cpsw_nuss_remove_tx_chns(struct am65_cpsw_common *common)
 
 		netif_napi_del(&tx_chn->napi_tx);
 	}
+}
+
+static void am65_cpsw_nuss_remove_tx_chns(struct am65_cpsw_common *common)
+{
+	struct device *dev = common->dev;
 
+	devm_remove_action(dev, am65_cpsw_nuss_free_tx_chns, common);
+	common->tx_ch_rate_msk = 0;
+	am65_cpsw_nuss_cleanup_tx_napi(common);
 	am65_cpsw_nuss_free_tx_chns(common);
 }
 
@@ -2355,25 +2360,27 @@ static void am65_cpsw_nuss_free_rx_chns(void *data)
 		k3_udma_glue_release_rx_chn(rx_chn->rx_chn);
 }
 
-static void am65_cpsw_nuss_remove_rx_chns(struct am65_cpsw_common *common)
+static void am65_cpsw_nuss_cleanup_rx_napi(struct am65_cpsw_common *common)
 {
 	struct device *dev = common->dev;
-	struct am65_cpsw_rx_chn *rx_chn;
 	struct am65_cpsw_rx_flow *flows;
 	int i;
 
-	rx_chn = &common->rx_chns;
-	flows = rx_chn->flows;
-	devm_remove_action(dev, am65_cpsw_nuss_free_rx_chns, common);
-
+	flows = common->rx_chns.flows;
 	for (i = 0; i < common->rx_ch_num_flows; i++) {
 		if (!(flows[i].irq < 0))
 			devm_free_irq(dev, flows[i].irq, &flows[i]);
 		netif_napi_del(&flows[i].napi_rx);
 	}
+}
 
-	am65_cpsw_nuss_free_rx_chns(common);
+static void am65_cpsw_nuss_remove_rx_chns(struct am65_cpsw_common *common)
+{
+	struct device *dev = common->dev;
 
+	devm_remove_action(dev, am65_cpsw_nuss_free_rx_chns, common);
+	am65_cpsw_nuss_cleanup_rx_napi(common);
+	am65_cpsw_nuss_free_rx_chns(common);
 	common->rx_flow_id_base = -1;
 }
 
@@ -2871,6 +2878,9 @@ static void am65_cpsw_nuss_cleanup_ndev(struct am65_cpsw_common *common)
 		if (port->ndev && port->ndev->reg_state == NETREG_REGISTERED)
 			unregister_netdev(port->ndev);
 	}
+
+	am65_cpsw_nuss_cleanup_rx_napi(common);
+	am65_cpsw_nuss_cleanup_tx_napi(common);
 }
 
 static void am65_cpsw_port_offload_fwd_mark_update(struct am65_cpsw_common *common)

Re: [PATCH net v3 2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

[Nicolas Pitre]

On Fri, 4 Oct 2024, Roger Quadros wrote:

> Hi Nicolas,
> 
> On 04/10/2024 07:10, Nicolas Pitre wrote:
> > From: Nicolas Pitre <npitre@baylibre.com>
> > 
> > Usage of devm_alloc_etherdev_mqs() conflicts with
> > am65_cpsw_nuss_cleanup_ndev() as the same struct net_device instances
> > get unregistered twice. Switch to alloc_etherdev_mqs() and make sure
> 
> Do we know why the same net device gets unregistered twice?

When using devm_alloc_etherdev_mqs() every successful allocation is put 
in a resource list tied to the device. When the driver is removed, 
there's a net device unregister from am65_cpsw_nuss_cleanup_ndev() and 
another one from devm_free_netdev().

We established in patch #1 that net devices must be unregistered before 
devlink_port_unregister() is invoked, meaning we can't rely on the 
implicit devm_free_netdev() as it happens too late, hence the explicit 
am65_cpsw_nuss_cleanup_ndev().

> > am65_cpsw_nuss_cleanup_ndev() unregisters and frees those net_device
> > instances properly.
> > 
> > With this, it is finally possible to rmmod the driver without oopsing
> > the kernel.
> > 
> > Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver")
> > Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
> > ---
> >  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 20 ++++++++++++--------
> >  1 file changed, 12 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> > index f6bc8a4dc6..e95457c988 100644
> > --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> > +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> > @@ -2744,10 +2744,9 @@ am65_cpsw_nuss_init_port_ndev(struct am65_cpsw_common *common, u32 port_idx)
> >  		return 0;
> >  
> >  	/* alloc netdev */
> > -	port->ndev = devm_alloc_etherdev_mqs(common->dev,
> > -					     sizeof(struct am65_cpsw_ndev_priv),
> > -					     AM65_CPSW_MAX_QUEUES,
> > -					     AM65_CPSW_MAX_QUEUES);
> > +	port->ndev = alloc_etherdev_mqs(sizeof(struct am65_cpsw_ndev_priv),
> > +					AM65_CPSW_MAX_QUEUES,
> > +					AM65_CPSW_MAX_QUEUES);
> 
> Can we solve this issue without doing this change as
> there are many error cases relying on devm managed freeing of netdev.

If you know of a way to do this differently I'm all ears.

About the many error cases needing the freeing of net devices, as far as 
I know they're all covered with this patch.

> I still can't see what we are doing wrong in existing code.

Did you try to rmmod this driver lately?


Nicolas

Re: [PATCH net v3 2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

[Roger Quadros]

On 04/10/2024 18:37, Nicolas Pitre wrote:
> On Fri, 4 Oct 2024, Roger Quadros wrote:
> 
>> Hi Nicolas,
>>
>> On 04/10/2024 07:10, Nicolas Pitre wrote:
>>> From: Nicolas Pitre <npitre@baylibre.com>
>>>
>>> Usage of devm_alloc_etherdev_mqs() conflicts with
>>> am65_cpsw_nuss_cleanup_ndev() as the same struct net_device instances
>>> get unregistered twice. Switch to alloc_etherdev_mqs() and make sure
>>
>> Do we know why the same net device gets unregistered twice?
> 
> When using devm_alloc_etherdev_mqs() every successful allocation is put 
> in a resource list tied to the device. When the driver is removed, 
> there's a net device unregister from am65_cpsw_nuss_cleanup_ndev() and 
> another one from devm_free_netdev().

I couldn't find out where devm_free_netdev() calls unregister_netdev().
Also we didn't use devm_register_netdev() so resource manager will not
call unregister_netdev().

> 
> We established in patch #1 that net devices must be unregistered before 
> devlink_port_unregister() is invoked, meaning we can't rely on the 
> implicit devm_free_netdev() as it happens too late, hence the explicit 
> am65_cpsw_nuss_cleanup_ndev().
> 
>>> am65_cpsw_nuss_cleanup_ndev() unregisters and frees those net_device
>>> instances properly.
>>>
>>> With this, it is finally possible to rmmod the driver without oopsing
>>> the kernel.
>>>
>>> Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver")
>>> Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
>>> ---
>>>  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 20 ++++++++++++--------
>>>  1 file changed, 12 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>>> index f6bc8a4dc6..e95457c988 100644
>>> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>>> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>>> @@ -2744,10 +2744,9 @@ am65_cpsw_nuss_init_port_ndev(struct am65_cpsw_common *common, u32 port_idx)
>>>  		return 0;
>>>  
>>>  	/* alloc netdev */
>>> -	port->ndev = devm_alloc_etherdev_mqs(common->dev,
>>> -					     sizeof(struct am65_cpsw_ndev_priv),
>>> -					     AM65_CPSW_MAX_QUEUES,
>>> -					     AM65_CPSW_MAX_QUEUES);
>>> +	port->ndev = alloc_etherdev_mqs(sizeof(struct am65_cpsw_ndev_priv),
>>> +					AM65_CPSW_MAX_QUEUES,
>>> +					AM65_CPSW_MAX_QUEUES);
>>
>> Can we solve this issue without doing this change as
>> there are many error cases relying on devm managed freeing of netdev.
> 
> If you know of a way to do this differently I'm all ears.

I sent another approach already. please check.
https://lore.kernel.org/all/67c9ede4-9751-4255-b752-27dd60495ff3@kernel.org/

> 
> About the many error cases needing the freeing of net devices, as far as 
> I know they're all covered with this patch.

No they are not. you now have to explicitly call free_netdev() in error paths of am65_cpsw_nuss_init_port_ndev().
I see 3 places directly returning error code.
i.e.
        default:
                dev_err(dev, "selected phy-mode is not supported\n");
                return -EOPNOTSUPP;
        }
...
        if (IS_ERR(phylink))
                return PTR_ERR(phylink);
...
        ndev_priv->stats = netdev_alloc_pcpu_stats(struct am65_cpsw_ndev_stats);
        if (!ndev_priv->stats)
                return -ENOMEM;

> 
>> I still can't see what we are doing wrong in existing code.
> 
> Did you try to rmmod this driver lately?

Yes and it throws an oops, so we do need a fix.
> 
> 
> Nicolas

-- 
cheers,
-roger

Re: [PATCH net v3 2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

[Nicolas Pitre]

On Fri, 4 Oct 2024, Roger Quadros wrote:

> 
> 
> On 04/10/2024 18:37, Nicolas Pitre wrote:
> >>> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> >>> index f6bc8a4dc6..e95457c988 100644
> >>> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> >>> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> >>> @@ -2744,10 +2744,9 @@ am65_cpsw_nuss_init_port_ndev(struct am65_cpsw_common *common, u32 port_idx)
> >>>  		return 0;
> >>>  
> >>>  	/* alloc netdev */
> >>> -	port->ndev = devm_alloc_etherdev_mqs(common->dev,
> >>> -					     sizeof(struct am65_cpsw_ndev_priv),
> >>> -					     AM65_CPSW_MAX_QUEUES,
> >>> -					     AM65_CPSW_MAX_QUEUES);
> >>> +	port->ndev = alloc_etherdev_mqs(sizeof(struct am65_cpsw_ndev_priv),
> >>> +					AM65_CPSW_MAX_QUEUES,
> >>> +					AM65_CPSW_MAX_QUEUES);
> >>
> >> Can we solve this issue without doing this change as
> >> there are many error cases relying on devm managed freeing of netdev.
> > 
> > If you know of a way to do this differently I'm all ears.
> 
> I sent another approach already. please check.

Slowly being built.

> > About the many error cases needing the freeing of net devices, as far as 
> > I know they're all covered with this patch.
> 
> No they are not. you now have to explicitly call free_netdev() in error paths of am65_cpsw_nuss_init_port_ndev().

And it does. If am65_cpsw_nuss_init_ndevs() fails then it frees them 
all. Same as with am65_cpsw_nuss_phylink_cleanup().


Nicolas

Re: [PATCH net v3 2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

[Nicolas Pitre]

On Fri, 4 Oct 2024, Roger Quadros wrote:

> > If you know of a way to do this differently I'm all ears.
> 
> I sent another approach already. please check.
> https://lore.kernel.org/all/67c9ede4-9751-4255-b752-27dd60495ff3@kernel.org/

Seems to work correctly.

Still... given this paragraph found in Documentation/process/maintainer-netdev.rst:

|Netdev remains skeptical about promises of all "auto-cleanup" APIs,
|including even ``devm_`` helpers, historically. They are not the preferred
|style of implementation, merely an acceptable one.

and given my solution is way simpler, I tend to also prefer it over yours.

But I'm not the maintainer nor even a significant contributor here so as 
long as the issue is fixed I won't mind.

> > About the many error cases needing the freeing of net devices, as far as 
> > I know they're all covered with this patch.
> 
> No they are not.

As I said yesterday, I do still stand by my affirmation that they are.
Please look at the entire return path and you'll see that everything is 
covered.


Nicolas

Re: [PATCH net v3 2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

[Roger Quadros]

On 05/10/2024 23:26, Nicolas Pitre wrote:
> On Fri, 4 Oct 2024, Roger Quadros wrote:
> 
>>> If you know of a way to do this differently I'm all ears.
>>
>> I sent another approach already. please check.
>> https://lore.kernel.org/all/67c9ede4-9751-4255-b752-27dd60495ff3@kernel.org/
> 
> Seems to work correctly.
> 
> Still... given this paragraph found in Documentation/process/maintainer-netdev.rst:
> 
> |Netdev remains skeptical about promises of all "auto-cleanup" APIs,
> |including even ``devm_`` helpers, historically. They are not the preferred
> |style of implementation, merely an acceptable one.
> 
> and given my solution is way simpler, I tend to also prefer it over yours.

OK. Let's go with yours as it makes the driver more compliant to netdev
guidelines.

> 
> But I'm not the maintainer nor even a significant contributor here so as 
> long as the issue is fixed I won't mind.
> 
>>> About the many error cases needing the freeing of net devices, as far as 
>>> I know they're all covered with this patch.
>>
>> No they are not.
> 
> As I said yesterday, I do still stand by my affirmation that they are.
> Please look at the entire return path and you'll see that everything is 
> covered.

Indeed, my bad. It wasn't obvious by just looking at the patch but when looking at
the code it is called via am65_cpsw_nuss_cleanup_ndev().

> 
> 
> Nicolas

-- 
cheers,
-roger

Re: [PATCH net v3 2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

[Roger Quadros]

On 04/10/2024 07:10, Nicolas Pitre wrote:
> From: Nicolas Pitre <npitre@baylibre.com>
> 
> Usage of devm_alloc_etherdev_mqs() conflicts with
> am65_cpsw_nuss_cleanup_ndev() as the same struct net_device instances
> get unregistered twice. Switch to alloc_etherdev_mqs() and make sure
> am65_cpsw_nuss_cleanup_ndev() unregisters and frees those net_device
> instances properly.
> 
> With this, it is finally possible to rmmod the driver without oopsing
> the kernel.
> 
> Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver")
> Signed-off-by: Nicolas Pitre <npitre@baylibre.com>

Reviewed-by: Roger Quadros <roger@kernel.org>

Re: [PATCH net v3 0/2] fix ti-am65-cpsw-nuss module removal

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Fri,  4 Oct 2024 00:10:32 -0400 you wrote:
> Fix issues preventing rmmod of ti-am65-cpsw-nuss from working properly.
> 
> v3:
> 
>   - more patch submission minutiae
> 
> v2: https://lore.kernel.org/netdev/20241003172105.2712027-2-nico@fluxnic.net/T/
> 
> [...]

Here is the summary with links:
  - [net,v3,1/2] net: ethernet: ti: am65-cpsw: prevent WARN_ON upon module removal
    https://git.kernel.org/netdev/net/c/47f9605484a8
  - [net,v3,2/2] net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal
    https://git.kernel.org/netdev/net/c/03c96bc9d3d2

You are awesome, thank you!
-- 
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