netdev - Re: [PATCH v17 12/22] sfc: get endpoint decoder

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Message-ID: <6a2cb965-32a6-4cce-9072-aa815e7181c0@amd.com>
Date: Fri, 4 Jul 2025 15:51:00 +0100
From: Alejandro Lucero Palau <alucerop@....com>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>,
 alejandro.lucero-palau@....com
Cc: linux-cxl@...r.kernel.org, netdev@...r.kernel.org,
 dan.j.williams@...el.com, edward.cree@....com, davem@...emloft.net,
 kuba@...nel.org, pabeni@...hat.com, edumazet@...gle.com,
 dave.jiang@...el.com, Martin Habets <habetsm.xilinx@...il.com>,
 Edward Cree <ecree.xilinx@...il.com>
Subject: Re: [PATCH v17 12/22] sfc: get endpoint decoder


On 6/27/25 10:10, Jonathan Cameron wrote:
> On Tue, 24 Jun 2025 15:13:45 +0100
> <alejandro.lucero-palau@....com> wrote:
>
>> From: Alejandro Lucero <alucerop@....com>
>>
>> Use cxl api for getting DPA (Device Physical Address) to use through an
>> endpoint decoder.
>>
>> Signed-off-by: Alejandro Lucero <alucerop@....com>
>> Reviewed-by: Martin Habets <habetsm.xilinx@...il.com>
>> Acked-by: Edward Cree <ecree.xilinx@...il.com>
>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
>> ---
>>   drivers/net/ethernet/sfc/Kconfig   |  1 +
>>   drivers/net/ethernet/sfc/efx_cxl.c | 32 +++++++++++++++++++++++++++++-
>>   2 files changed, 32 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/sfc/Kconfig b/drivers/net/ethernet/sfc/Kconfig
>> index 979f2801e2a8..e959d9b4f4ce 100644
>> --- a/drivers/net/ethernet/sfc/Kconfig
>> +++ b/drivers/net/ethernet/sfc/Kconfig
>> @@ -69,6 +69,7 @@ config SFC_MCDI_LOGGING
>>   config SFC_CXL
>>   	bool "Solarflare SFC9100-family CXL support"
>>   	depends on SFC && CXL_BUS >= SFC
>> +	depends on CXL_REGION
>>   	default SFC
>>   	help
>>   	  This enables SFC CXL support if the kernel is configuring CXL for
>> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
>> index e2d52ed49535..c0adfd99cc78 100644
>> --- a/drivers/net/ethernet/sfc/efx_cxl.c
>> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
>> @@ -22,6 +22,7 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
>>   {
>>   	struct efx_nic *efx = &probe_data->efx;
>>   	struct pci_dev *pci_dev = efx->pci_dev;
>> +	resource_size_t max_size;
>>   	struct efx_cxl *cxl;
>>   	u16 dvsec;
>>   	int rc;
>> @@ -86,13 +87,42 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
>>   		return PTR_ERR(cxl->cxlmd);
>>   	}
>>   
>> +	cxl->endpoint = cxl_acquire_endpoint(cxl->cxlmd);
>> +	if (IS_ERR(cxl->endpoint))
>> +		return PTR_ERR(cxl->endpoint);
>> +
>> +	cxl->cxlrd = cxl_get_hpa_freespace(cxl->cxlmd, 1,
>> +					   CXL_DECODER_F_RAM | CXL_DECODER_F_TYPE2,
>> +					   &max_size);
>> +
>> +	if (IS_ERR(cxl->cxlrd)) {
>> +		pci_err(pci_dev, "cxl_get_hpa_freespace failed\n");
>> +		rc = PTR_ERR(cxl->cxlrd);
>> +		goto endpoint_release;
>> +	}
>> +
>> +	if (max_size < EFX_CTPIO_BUFFER_SIZE) {
>> +		pci_err(pci_dev, "%s: not enough free HPA space %pap < %u\n",
>> +			__func__, &max_size, EFX_CTPIO_BUFFER_SIZE);
>> +		rc = -ENOSPC;
>> +		goto put_root_decoder;
>> +	}
>> +
>>   	probe_data->cxl = cxl;
>>   
>> -	return 0;
>> +	goto endpoint_release;
> I'd avoid the spiders nest here and just duplicate the release
> or if you really want to avoid that duplication, factor out everything where
> it is held into another function and have aqcuire/function/release as all that
> is seen here.
>

I'll duplicate the release for the default successful return.

Thanks


>> +
>> +put_root_decoder:
>> +	cxl_put_root_decoder(cxl->cxlrd);
>> +endpoint_release:
>> +	cxl_release_endpoint(cxl->cxlmd, cxl->endpoint);
>> +	return rc;
>>   }
>>   
>>   void efx_cxl_exit(struct efx_probe_data *probe_data)
>>   {
>> +	if (probe_data->cxl)
>> +		cxl_put_root_decoder(probe_data->cxl->cxlrd);
>>   }
>>   
>>   MODULE_IMPORT_NS("CXL");