Re: [Linux-kernel-mentees] [RFC 1/3] Initialize devlink health dump framework for the dlge driver

[Coiby Xu <coiby.xu@gmail.com>]

On Sun, Aug 16, 2020 at 11:56:40AM +0900, Benjamin Poirier wrote:
>On 2020-08-15 00:05 +0800, Coiby Xu wrote:
>> Initialize devlink health dump framework for the dlge driver so the
>> coredump could be done via devlink.
>>
>> Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
>> ---
>>  drivers/staging/qlge/Makefile      |  2 +-
>>  drivers/staging/qlge/qlge.h        |  9 +++++++
>>  drivers/staging/qlge/qlge_health.c | 43 ++++++++++++++++++++++++++++++
>>  drivers/staging/qlge/qlge_health.h |  2 ++
>>  drivers/staging/qlge/qlge_main.c   | 21 +++++++++++++++
>>  5 files changed, 76 insertions(+), 1 deletion(-)
>>  create mode 100644 drivers/staging/qlge/qlge_health.c
>>  create mode 100644 drivers/staging/qlge/qlge_health.h
>>
>> diff --git a/drivers/staging/qlge/Makefile b/drivers/staging/qlge/Makefile
>> index 1dc2568e820c..0a1e4c8dd546 100644
>> --- a/drivers/staging/qlge/Makefile
>> +++ b/drivers/staging/qlge/Makefile
>> @@ -5,4 +5,4 @@
>>
>>  obj-$(CONFIG_QLGE) += qlge.o
>>
>> -qlge-objs := qlge_main.o qlge_dbg.o qlge_mpi.o qlge_ethtool.o
>> +qlge-objs := qlge_main.o qlge_dbg.o qlge_mpi.o qlge_ethtool.o qlge_health.o
>> diff --git a/drivers/staging/qlge/qlge.h b/drivers/staging/qlge/qlge.h
>> index fc8c5ca8935d..055ded6dab60 100644
>> --- a/drivers/staging/qlge/qlge.h
>> +++ b/drivers/staging/qlge/qlge.h
>> @@ -2061,6 +2061,14 @@ struct nic_operations {
>>  	int (*port_initialize) (struct ql_adapter *);
>>  };
>>
>
>This patch doesn't apply over the latest staging tree. I think your tree
>is missing commit d923bb6bf508 ("staging: qlge: qlge.h: Function
>definition arguments should have names.")

Thank you for applying the patch to test it! I had incorrect
understanding about the word "RFC" and didn't do a rebase onto
the latest staging tree.

>
>> +
>> +
>> +struct qlge_devlink {
>> +        struct ql_adapter *qdev;
>> +        struct net_device *ndev;
>
>I don't have experience implementing devlink callbacks but looking at
>some other devlink users (mlx4, ionic, ice), all of them use devlink
>priv space for their main private structure. That would be struct
>ql_adapter in this case. Is there a good reason to stray from that
>pattern?
>
>> +        struct devlink_health_reporter *reporter;
>> +};
>> +
>>  /*
>>   * The main Adapter structure definition.
>>   * This structure has all fields relevant to the hardware.
>> @@ -2078,6 +2086,7 @@ struct ql_adapter {
>>  	struct pci_dev *pdev;
>>  	struct net_device *ndev;	/* Parent NET device */
>>
>> +	struct qlge_devlink *devlink;
>>  	/* Hardware information */
>>  	u32 chip_rev_id;
>>  	u32 fw_rev_id;
>> diff --git a/drivers/staging/qlge/qlge_health.c b/drivers/staging/qlge/qlge_health.c
>> new file mode 100644
>> index 000000000000..292f6b1827e1
>> --- /dev/null
>> +++ b/drivers/staging/qlge/qlge_health.c
>> @@ -0,0 +1,43 @@
>> +#include "qlge.h"
>> +#include "qlge_health.h"
>> +
>> +static int
>> +qlge_reporter_coredump(struct devlink_health_reporter *reporter,
>> +			struct devlink_fmsg *fmsg, void *priv_ctx,
>> +			struct netlink_ext_ack *extack)
>> +{
>> +	return 0;
>> +}
>> +
>> +static const struct devlink_health_reporter_ops qlge_reporter_ops = {
>> +		.name = "dummy",
>> +		.dump = qlge_reporter_coredump,
>> +};
>
>I think
>	select NET_DEVLINK
>should be added to drivers/staging/qlge/Kconfig

Thank you for reminding me!

>
>> +
>> +int qlge_health_create_reporters(struct qlge_devlink *priv)
>> +{
>> +	int err;
>> +
>> +	struct devlink_health_reporter *reporter;
>> +	struct devlink *devlink;
>> +
>> +	devlink = priv_to_devlink(priv);
>> +	reporter =
>> +		devlink_health_reporter_create(devlink, &qlge_reporter_ops,
>> +					       0,
>> +					       priv);
>> +	if (IS_ERR(reporter)) {
>> +		netdev_warn(priv->ndev,
>> +			    "Failed to create reporter, err = %ld\n",
>> +			    PTR_ERR(reporter));
>> +		return PTR_ERR(reporter);
>> +	}
>> +	priv->reporter = reporter;
>> +
>> +	if (err)
>> +		return err;
>> +
>> +	return 0;
>> +}
>> +
>> +
>
>Stray newlines

Will fix it in v1.

>
>> diff --git a/drivers/staging/qlge/qlge_health.h b/drivers/staging/qlge/qlge_health.h
>> new file mode 100644
>> index 000000000000..07d3bafab845
>> --- /dev/null
>> +++ b/drivers/staging/qlge/qlge_health.h
>> @@ -0,0 +1,2 @@
>> +#include <net/devlink.h>
>> +int qlge_health_create_reporters(struct qlge_devlink *priv);
>
>I would suggest to put this in qlge.h instead of creating a new file.

Although there are only two lines for now, is it possible qlge will add
more devlink code? If that's the case, a file to single out these code
is necessary as is the same to some other drivers,

     $ find drivers -name *health*.h
     drivers/net/ethernet/mellanox/mlx5/core/en/health.h

     $ find drivers -name *devlink*.h
     drivers/net/ethernet/huawei/hinic/hinic_devlink.h
     drivers/net/ethernet/mellanox/mlx5/core/devlink.h
     drivers/net/ethernet/mellanox/mlx5/core/en/devlink.h
     drivers/net/ethernet/intel/ice/ice_devlink.h
     drivers/net/ethernet/pensando/ionic/ionic_devlink.h
     drivers/net/ethernet/broadcom/bnxt/bnxt_devlink.h

>
>> diff --git a/drivers/staging/qlge/qlge_main.c b/drivers/staging/qlge/qlge_main.c
>> index 1650de13842f..b2be7f4b7dd6 100644
>> --- a/drivers/staging/qlge/qlge_main.c
>> +++ b/drivers/staging/qlge/qlge_main.c
>> @@ -42,6 +42,7 @@
>>  #include <net/ip6_checksum.h>
>>
>>  #include "qlge.h"
>> +#include "qlge_health.h"
>>
>>  char qlge_driver_name[] = DRV_NAME;
>>  const char qlge_driver_version[] = DRV_VERSION;
>> @@ -4550,6 +4551,8 @@ static void ql_timer(struct timer_list *t)
>>  	mod_timer(&qdev->timer, jiffies + (5 * HZ));
>>  }
>>
>> +static const struct devlink_ops qlge_devlink_ops;
>> +
>>  static int qlge_probe(struct pci_dev *pdev,
>>  		      const struct pci_device_id *pci_entry)
>>  {
>> @@ -4557,6 +4560,13 @@ static int qlge_probe(struct pci_dev *pdev,
>>  	struct ql_adapter *qdev = NULL;
>>  	static int cards_found;
>>  	int err = 0;
>> +	struct devlink *devlink;
>> +	struct qlge_devlink *qlge_dl;
>> +
>> +	devlink = devlink_alloc(&qlge_devlink_ops, sizeof(struct qlge_devlink));
>> +	if (!devlink)
>> +		return -ENOMEM;
>> +	qlge_dl = devlink_priv(devlink);
>>
>>  	ndev = alloc_etherdev_mq(sizeof(struct ql_adapter),
>>  				 min(MAX_CPUS,
>> @@ -4615,6 +4625,15 @@ static int qlge_probe(struct pci_dev *pdev,
>>  		free_netdev(ndev);
>>  		return err;
>>  	}
>> +
>> +	err = devlink_register(devlink, &pdev->dev);
>> +	if (err)
>> +		devlink_free(devlink);
>
>Are you sure it's safe to continue devlink init after an error here?
>Again, that does not resemble usage of devlink in other drivers (ex.
>bnxt).

Thank you for pointing out my neglect!

>
>> +
>> +	qlge_health_create_reporters(qlge_dl);
>> +	qlge_dl->qdev = qdev;
>> +	qlge_dl->ndev = ndev;
>> +	qdev->devlink = qlge_dl;
>>  	/* Start up the timer to trigger EEH if
>>  	 * the bus goes dead
>>  	 */
>> @@ -4647,6 +4666,8 @@ static void qlge_remove(struct pci_dev *pdev)
>>  	unregister_netdev(ndev);
>>  	ql_release_all(pdev);
>>  	pci_disable_device(pdev);
>> +	devlink_unregister(priv_to_devlink(qdev->devlink));
>> +	devlink_health_reporter_destroy(qdev->devlink->reporter);
>
>Isn't the order of those two calls mixed up?

I haven't studied the code to figure out why but other drivers also
use the same order.
>
>>  	free_netdev(ndev);
>>  }
>>
>> --
>> 2.27.0
>>

--
Best regards,
Coiby
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