Re: [EXTERNAL] Re: [PATCH net-next v3 2/3] net: ti: icssg-prueth: introduce and use prueth_swdata struct for SWDATA

["Malladi, Meghana" <m-malladi@ti.com>]

On 2/26/2025 3:59 PM, Dan Carpenter wrote:
> On Mon, Feb 24, 2025 at 04: 31: 01PM +0530, Meghana Malladi wrote: > 
> From: Roger Quadros <rogerq@ kernel. org> > > We have different cases 
> for SWDATA (skb, page, cmd, etc) > so it is better to have a dedicated 
> data structure for
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> On Mon, Feb 24, 2025 at 04:31:01PM +0530, Meghana Malladi wrote:
>> From: Roger Quadros <rogerq@kernel.org>
>> 
>> We have different cases for SWDATA (skb, page, cmd, etc)
>> so it is better to have a dedicated data structure for that.
>> We can embed the type field inside the struct and use it
>> to interpret the data in completion handlers.
>> 
>> Increase SWDATA size to 48 so we have some room to add
>> more data if required.
> 
> What is the "SWDATA size"?  Where is that specified?  Is
> that a variable or a define or the size of a struct or
> what?
> 

Will be removing this line, since "increase SWDATA size" change is not 
applicable anymore. It is a macro PRUETH_NAV_SW_DATA_SIZE used to define 
the size held for swdata.

>> 
>> Signed-off-by: Roger Quadros <rogerq@kernel.org>
>> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
>> Signed-off-by: Meghana Malladi <m-malladi@ti.com>
>> ---
>> Changes since v2 (v3-v2):
>> - Fix leaking tx descriptor in emac_tx_complete_packets()
>> - Free rx descriptor if swdata type is not page in emac_rx_packet()
>> - Revert back the size of PRUETH_NAV_SW_DATA_SIZE
>> - Use build time check for prueth_swdata size
>> - re-write prueth_swdata to have enum type as first member in the struct
>> and prueth_data union embedded in the struct
>> 
>> All the above changes have been suggested by Roger Quadros <rogerq@kernel.org>
>> 
>>  drivers/net/ethernet/ti/icssg/icssg_common.c  | 52 +++++++++++++------
>>  drivers/net/ethernet/ti/icssg/icssg_prueth.c  |  3 ++
>>  drivers/net/ethernet/ti/icssg/icssg_prueth.h  | 16 ++++++
>>  .../net/ethernet/ti/icssg/icssg_prueth_sr1.c  |  4 +-
>>  4 files changed, 57 insertions(+), 18 deletions(-)
>> 
>> diff --git a/drivers/net/ethernet/ti/icssg/icssg_common.c b/drivers/net/ethernet/ti/icssg/icssg_common.c
>> index acbb79ad8b0c..01eeabe83eff 100644
>> --- a/drivers/net/ethernet/ti/icssg/icssg_common.c
>> +++ b/drivers/net/ethernet/ti/icssg/icssg_common.c
>> @@ -136,12 +136,12 @@ int emac_tx_complete_packets(struct prueth_emac *emac, int chn,
>>  	struct net_device *ndev = emac->ndev;
>>  	struct cppi5_host_desc_t *desc_tx;
>>  	struct netdev_queue *netif_txq;
>> +	struct prueth_swdata *swdata;
>>  	struct prueth_tx_chn *tx_chn;
>>  	unsigned int total_bytes = 0;
>>  	struct sk_buff *skb;
>>  	dma_addr_t desc_dma;
>>  	int res, num_tx = 0;
>> -	void **swdata;
>>  
>>  	tx_chn = &emac->tx_chns[chn];
>>  
>> @@ -163,12 +163,19 @@ int emac_tx_complete_packets(struct prueth_emac *emac, int chn,
>>  		swdata = cppi5_hdesc_get_swdata(desc_tx);
>>  
>>  		/* was this command's TX complete? */
>> -		if (emac->is_sr1 && *(swdata) == emac->cmd_data) {
>> +		if (emac->is_sr1 && (void *)(swdata) == emac->cmd_data) {
> 
> I don't think this conversion is correct.  You still need to say:
> 
> 		if (emac->is_sr1 && swdata->data.something == emac->cmd_data) {
> 
> Where something is probably "page".
> 

Yes you are right. This needs to be changes to:

if (emac->is_sr1 && swdata->data.cmd== emac->cmd_data) {

This issue can be addressed more cleanly with the fix Roger mentioned 
here: 
https://lore.kernel.org/all/3d3d180a-12b7-4bee-8172-700f0dae2439@kernel.org/

> regards,
> dan carpenter
> 
>>  			prueth_xmit_free(tx_chn, desc_tx);
>>  			continue;
>>  		}
>>  
>> -		skb = *(swdata);
>> +		if (swdata->type != PRUETH_SWDATA_SKB) {
>> +			netdev_err(ndev, "tx_complete: invalid swdata type %d\n", swdata->type);
>> +			prueth_xmit_free(tx_chn, desc_tx);
>> +			budget++;
>> +			continue;
>> +		}
>