Message-ID: <b6ed7b0b-9262-3578-1d88-4c848d1aea82@intel.com>
Date:   Wed, 12 Apr 2023 16:10:18 -0700
From:   "Tantilov, Emil S" <emil.s.tantilov@...el.com>
To:     Leon Romanovsky <leon@...nel.org>,
        Pavan Kumar Linga <pavan.kumar.linga@...el.com>
CC:     <intel-wired-lan@...ts.osuosl.org>, <netdev@...r.kernel.org>,
        <joshua.a.hay@...el.com>, <sridhar.samudrala@...el.com>,
        <jesse.brandeburg@...el.com>, <anthony.l.nguyen@...el.com>,
        <willemb@...gle.com>, <decot@...gle.com>, <pabeni@...hat.com>,
        <kuba@...nel.org>, <edumazet@...gle.com>, <davem@...emloft.net>,
        Phani Burra <phani.r.burra@...el.com>,
        Alan Brady <alan.brady@...el.com>,
        Madhu Chittim <madhu.chittim@...el.com>,
        Shailendra Bhatnagar <shailendra.bhatnagar@...el.com>
Subject: Re: [PATCH net-next v2 02/15] idpf: add module register and probe
 functionality



On 4/11/2023 5:36 AM, Leon Romanovsky wrote:
> On Mon, Apr 10, 2023 at 06:13:41PM -0700, Pavan Kumar Linga wrote:
>> From: Phani Burra <phani.r.burra@...el.com>
>>
>> Add the required support to register IDPF PCI driver, as well as
>> probe and remove call backs. Enable the PCI device and request
>> the kernel to reserve the memory resources that will be used by the
>> driver. Finally map the BAR0 address space.
>>
>> PCI IDs table is intentionally left blank to prevent the kernel from
>> probing the device with the incomplete driver. It will be added
>> in the last patch of the series.
>>
>> Signed-off-by: Phani Burra <phani.r.burra@...el.com>
>> Co-developed-by: Alan Brady <alan.brady@...el.com>
>> Signed-off-by: Alan Brady <alan.brady@...el.com>
>> Co-developed-by: Madhu Chittim <madhu.chittim@...el.com>
>> Signed-off-by: Madhu Chittim <madhu.chittim@...el.com>
>> Co-developed-by: Shailendra Bhatnagar <shailendra.bhatnagar@...el.com>
>> Signed-off-by: Shailendra Bhatnagar <shailendra.bhatnagar@...el.com>
>> Co-developed-by: Pavan Kumar Linga <pavan.kumar.linga@...el.com>
>> Signed-off-by: Pavan Kumar Linga <pavan.kumar.linga@...el.com>
>> Reviewed-by: Sridhar Samudrala <sridhar.samudrala@...el.com>
>> Reviewed-by: Willem de Bruijn <willemb@...gle.com>
>> ---
>>   drivers/net/ethernet/intel/Kconfig            | 11 +++
>>   drivers/net/ethernet/intel/Makefile           |  1 +
>>   drivers/net/ethernet/intel/idpf/Makefile      | 10 ++
>>   drivers/net/ethernet/intel/idpf/idpf.h        | 27 ++++++
>>   .../net/ethernet/intel/idpf/idpf_controlq.h   | 14 +++
>>   drivers/net/ethernet/intel/idpf/idpf_lib.c    | 96 +++++++++++++++++++
>>   drivers/net/ethernet/intel/idpf/idpf_main.c   | 70 ++++++++++++++
>>   7 files changed, 229 insertions(+)
>>   create mode 100644 drivers/net/ethernet/intel/idpf/Makefile
>>   create mode 100644 drivers/net/ethernet/intel/idpf/idpf.h
>>   create mode 100644 drivers/net/ethernet/intel/idpf/idpf_controlq.h
>>   create mode 100644 drivers/net/ethernet/intel/idpf/idpf_lib.c
>>   create mode 100644 drivers/net/ethernet/intel/idpf/idpf_main.c
> 
> <...>
> 
>> +/**
>> + * idpf_remove_common - Device removal routine
>> + * @pdev: PCI device information struct
>> + */
>> +void idpf_remove_common(struct pci_dev *pdev)
>> +{
>> +	struct idpf_adapter *adapter = pci_get_drvdata(pdev);
>> +
>> +	if (!adapter)
> 
> How is it possible to have adapter be NULL here?

I think it is just defensive check since remove can be called on error 
code path, but in general you're right and we likely don't need it. Will 
remove in v3.

> 
>> +		return;
>> +
>> +	pci_disable_pcie_error_reporting(pdev);
>> +}
>> diff --git a/drivers/net/ethernet/intel/idpf/idpf_main.c b/drivers/net/ethernet/intel/idpf/idpf_main.c
>> new file mode 100644
>> index 000000000000..617df9b924fa
>> --- /dev/null
>> +++ b/drivers/net/ethernet/intel/idpf/idpf_main.c
>> @@ -0,0 +1,70 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/* Copyright (C) 2023 Intel Corporation */
>> +
>> +#include "idpf.h"
>> +
>> +#define DRV_SUMMARY	"Infrastructure Data Path Function Linux Driver"
>> +
>> +MODULE_DESCRIPTION(DRV_SUMMARY);
>> +MODULE_LICENSE("GPL");
>> +
>> +/**
>> + * idpf_remove - Device removal routine
>> + * @pdev: PCI device information struct
>> + */
>> +static void idpf_remove(struct pci_dev *pdev)
>> +{
>> +	struct idpf_adapter *adapter = pci_get_drvdata(pdev);
>> +
>> +	if (!adapter)
> 
> Ditto

Will remove in v3.

>> +		return;
>> +
>> +	idpf_remove_common(pdev);
>> +	pci_set_drvdata(pdev, NULL);
>> +}
>> +
>> +/**
>> + * idpf_shutdown - PCI callback for shutting down device
>> + * @pdev: PCI device information struct
>> + */
>> +static void idpf_shutdown(struct pci_dev *pdev)
>> +{
>> +	idpf_remove(pdev);
>> +
>> +	if (system_state == SYSTEM_POWER_OFF)
>> +		pci_set_power_state(pdev, PCI_D3hot);
>> +}
>> +
>> +/**
>> + * idpf_probe - Device initialization routine
>> + * @pdev: PCI device information struct
>> + * @ent: entry in idpf_pci_tbl
>> + *
>> + * Returns 0 on success, negative on failure
>> + */
>> +static int idpf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>> +{
>> +	struct idpf_adapter *adapter;
>> +
>> +	adapter = devm_kzalloc(&pdev->dev, sizeof(*adapter), GFP_KERNEL);
> 
> Why devm_kzalloc() and not kzalloc?
It provides managed memory allocation on probe, which seems to be the 
preferred method in that case.

>> +	if (!adapter)
>> +		return -ENOMEM;
>> +
>> +	return idpf_probe_common(pdev, adapter);
> 
> There is no need in idpf_probe_common/idpf_remove_common functions and
> they better be embedded here. They called only once and just obfuscate
> the code.

Will remove in v3.

>> +}
>> +
>> +/* idpf_pci_tbl - PCI Dev idpf ID Table
>> + */
>> +static const struct pci_device_id idpf_pci_tbl[] = {
>> +	{ /* Sentinel */ }
> 
> What does it mean empty pci_device_id table?

Device ID's are added later, but it does make sense to be in this patch 
instead. Will fix in v3.

>> +};
>> +MODULE_DEVICE_TABLE(pci, idpf_pci_tbl);
>> +
>> +static struct pci_driver idpf_driver = {
>> +	.name			= KBUILD_MODNAME,
>> +	.id_table		= idpf_pci_tbl,
>> +	.probe			= idpf_probe,
>> +	.remove			= idpf_remove,
>> +	.shutdown		= idpf_shutdown,
>> +};
>> +module_pci_driver(idpf_driver);
>> -- 
>> 2.37.3
>>

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