Subject: Re: [PATCH v3 net-next 19/19] ionic: Add basic devlink interface

From: Jiri Pirko <[email-masked]>
Date: Mon, 8 Jul 2019 22:03:50 +0200

Mon, Jul 08, 2019 at 09:58:09PM CEST, [email-masked] wrote:
>On 7/8/19 12:34 PM, Jiri Pirko wrote:
>> Mon, Jul 08, 2019 at 09:25:32PM CEST, [email-masked] wrote:
>> > Add a devlink interface for access to information that isn't
>> > normally available through ethtool or the iplink interface.
>> > 
>> > Example:
>> > 	$ ./devlink -j -p dev info pci/0000:b6:00.0
>> > 	{
>> > 	    "info": {
>> > 		"pci/0000:b6:00.0": {
>> > 		    "driver": "ionic",
>> > 		    "serial_number": "FLM18420073",
>> > 		    "versions": {
>> > 			"fixed": {
>> > 			    "fw_version": "0.11.0-50",
>> > 			    "fw_status": "0x1",
>> > 			    "fw_heartbeat": "0x716ce",
>> > 			    "asic_type": "0x0",
>> > 			    "asic_rev": "0x0"
>> > 			}
>> > 		    }
>> > 		}
>> > 	    }
>> > 	}
>> > 
>> > Signed-off-by: Shannon Nelson <[email-masked]>
>> > ---
>> > drivers/net/ethernet/pensando/ionic/Makefile  |  2 +-
>> > drivers/net/ethernet/pensando/ionic/ionic.h   |  1 +
>> > .../ethernet/pensando/ionic/ionic_bus_pci.c   |  7 ++
>> > .../ethernet/pensando/ionic/ionic_devlink.c   | 89 +++++++++++++++++++
>> > .../ethernet/pensando/ionic/ionic_devlink.h   | 12 +++
>> > 5 files changed, 110 insertions(+), 1 deletion(-)
>> > create mode 100644 drivers/net/ethernet/pensando/ionic/ionic_devlink.c
>> > create mode 100644 drivers/net/ethernet/pensando/ionic/ionic_devlink.h
>> > 
>> > diff --git a/drivers/net/ethernet/pensando/ionic/Makefile b/drivers/net/ethernet/pensando/ionic/Makefile
>> > index 4f3cfbf36c23..ce187c7b33a8 100644
>> > --- a/drivers/net/ethernet/pensando/ionic/Makefile
>> > +++ b/drivers/net/ethernet/pensando/ionic/Makefile
>> > @@ -5,4 +5,4 @@ obj-$(CONFIG_IONIC) := ionic.o
>> > 
>> > ionic-y := ionic_main.o ionic_bus_pci.o ionic_dev.o ionic_ethtool.o \
>> > 	   ionic_lif.o ionic_rx_filter.o ionic_txrx.o ionic_debugfs.o \
>> > -	   ionic_stats.o
>> > +	   ionic_stats.o ionic_devlink.o
>> > diff --git a/drivers/net/ethernet/pensando/ionic/ionic.h b/drivers/net/ethernet/pensando/ionic/ionic.h
>> > index cd08166f73a9..a0034bc5b4a1 100644
>> > --- a/drivers/net/ethernet/pensando/ionic/ionic.h
>> > +++ b/drivers/net/ethernet/pensando/ionic/ionic.h
>> > @@ -44,6 +44,7 @@ struct ionic {
>> > 	DECLARE_BITMAP(intrs, INTR_CTRL_REGS_MAX);
>> > 	struct work_struct nb_work;
>> > 	struct notifier_block nb;
>> > +	struct devlink *dl;
>> > };
>> > 
>> > struct ionic_admin_ctx {
>> > diff --git a/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c b/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c
>> > index 98c12b770c7f..a8c99254489f 100644
>> > --- a/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c
>> > +++ b/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c
>> > @@ -10,6 +10,7 @@
>> > #include "ionic_bus.h"
>> > #include "ionic_lif.h"
>> > #include "ionic_debugfs.h"
>> > +#include "ionic_devlink.h"
>> > 
>> > /* Supported devices */
>> > static const struct pci_device_id ionic_id_table[] = {
>> > @@ -212,9 +213,14 @@ static int ionic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>> > 		goto err_out_deinit_lifs;
>> > 	}
>> > 
>> > +	err = ionic_devlink_register(ionic);
>> > +	if (err)
>> > +		dev_err(dev, "Cannot register devlink (ignored): %d\n", err);
>> > +
>> > 	return 0;
>> > 
>> > err_out_deinit_lifs:
>> > +	ionic_devlink_unregister(ionic);
>> > 	ionic_lifs_deinit(ionic);
>> > err_out_free_lifs:
>> > 	ionic_lifs_free(ionic);
>> > @@ -247,6 +253,7 @@ static void ionic_remove(struct pci_dev *pdev)
>> > 	struct ionic *ionic = pci_get_drvdata(pdev);
>> > 
>> > 	if (ionic) {
>> > +		ionic_devlink_unregister(ionic);
>> > 		ionic_lifs_unregister(ionic);
>> > 		ionic_lifs_deinit(ionic);
>> > 		ionic_lifs_free(ionic);
>> > diff --git a/drivers/net/ethernet/pensando/ionic/ionic_devlink.c b/drivers/net/ethernet/pensando/ionic/ionic_devlink.c
>> > new file mode 100644
>> > index 000000000000..fbbfcdde292f
>> > --- /dev/null
>> > +++ b/drivers/net/ethernet/pensando/ionic/ionic_devlink.c
>> > @@ -0,0 +1,89 @@
>> > +// SPDX-License-Identifier: GPL-2.0
>> > +/* Copyright(c) 2017 - 2019 Pensando Systems, Inc */
>> > +
>> > +#include <linux/module.h>
>> > +#include <linux/netdevice.h>
>> > +
>> > +#include "ionic.h"
>> > +#include "ionic_bus.h"
>> > +#include "ionic_lif.h"
>> > +#include "ionic_devlink.h"
>> > +
>> > +struct ionic_devlink {
>> > +	struct ionic *ionic;
>> > +};
>> > +
>> > +static int ionic_dl_info_get(struct devlink *dl, struct devlink_info_req *req,
>> > +			     struct netlink_ext_ack *extack)
>> > +{
>> > +	struct ionic *ionic = *(struct ionic **)devlink_priv(dl);
>> > +	struct ionic_dev *idev = &ionic->idev;
>> > +	char buf[16];
>> > +	u32 val;
>> > +
>> > +	devlink_info_driver_name_put(req, DRV_NAME);
>> > +
>> > +	devlink_info_version_fixed_put(req, "fw_version",
>> > +				       idev->dev_info.fw_version);
>> > +
>> > +	val = ioread8(&idev->dev_info_regs->fw_status);
>> > +	snprintf(buf, sizeof(buf), "0x%x", val);
>> > +	devlink_info_version_fixed_put(req, "fw_status", buf);
>> > +
>> > +	val = ioread32(&idev->dev_info_regs->fw_heartbeat);
>> > +	snprintf(buf, sizeof(buf), "0x%x", val);
>> > +	devlink_info_version_fixed_put(req, "fw_heartbeat", buf);
>> > +
>> > +	snprintf(buf, sizeof(buf), "0x%x", idev->dev_info.asic_type);
>> > +	devlink_info_version_fixed_put(req, "asic_type", buf);
>> > +
>> > +	snprintf(buf, sizeof(buf), "0x%x", idev->dev_info.asic_rev);
>> > +	devlink_info_version_fixed_put(req, "asic_rev", buf);
>> > +
>> > +	devlink_info_serial_number_put(req, idev->dev_info.serial_num);
>> > +
>> > +	return 0;
>> > +}
>> > +
>> > +static const struct devlink_ops ionic_dl_ops = {
>> > +	.info_get	= ionic_dl_info_get,
>> > +};
>> > +
>> > +int ionic_devlink_register(struct ionic *ionic)
>> > +{
>> > +	struct devlink *dl;
>> > +	struct ionic **ip;
>> > +	int err;
>> > +
>> > +	dl = devlink_alloc(&ionic_dl_ops, sizeof(struct ionic *));
>> Oups. Something is wrong with your flow. The devlink alloc is allocating
>> the structure that holds private data (per-device data) for you. This is
>> misuse :/
>> 
>> You are missing one parent device struct apparently.
>> 
>> Oh, I think I see something like it. The unused "struct ionic_devlink".
>
>If I'm not mistaken, the alloc is only allocating enough for a pointer, not
>the whole per device struct, and a few lines down from here the pointer to
>the new devlink struct is assigned to ionic->dl.  This was based on what I
>found in the qed driver's qed_devlink_register(), and it all seems to work.

I'm not saying your code won't work. What I say is that you should have
a struct for device that would be allocated by devlink_alloc()

The ionic struct should be associated with devlink_port. That you are
missing too.

>
>That unused struct ionic_devlink does need to go away, it was superfluous
>after working out a better typecast off of devlink_priv().
>
>I'll remove the unused struct ionic_devlink, but I think the rest is okay.
>
>sln
>
>> 
>> 
>> > +	if (!dl) {
>> > +		dev_warn(ionic->dev, "devlink_alloc failed");
>> > +		return -ENOMEM;
>> > +	}
>> > +
>> > +	ip = (struct ionic **)devlink_priv(dl);
>> > +	*ip = ionic;
>> > +	ionic->dl = dl;
>> > +
>> > +	err = devlink_register(dl, ionic->dev);
>> > +	if (err) {
>> > +		dev_warn(ionic->dev, "devlink_register failed: %d\n", err);
>> > +		goto err_dl_free;
>> > +	}
>> > +
>> > +	return 0;
>> > +
>> > +err_dl_free:
>> > +	ionic->dl = NULL;
>> > +	devlink_free(dl);
>> > +	return err;
>> > +}
>> > +
>> > +void ionic_devlink_unregister(struct ionic *ionic)
>> > +{
>> > +	if (!ionic->dl)
>> > +		return;
>> > +
>> > +	devlink_unregister(ionic->dl);
>> > +	devlink_free(ionic->dl);
>> > +}
>> > diff --git a/drivers/net/ethernet/pensando/ionic/ionic_devlink.h b/drivers/net/ethernet/pensando/ionic/ionic_devlink.h
>> > new file mode 100644
>> > index 000000000000..35528884e29f
>> > --- /dev/null
>> > +++ b/drivers/net/ethernet/pensando/ionic/ionic_devlink.h
>> > @@ -0,0 +1,12 @@
>> > +/* SPDX-License-Identifier: GPL-2.0 */
>> > +/* Copyright(c) 2017 - 2019 Pensando Systems, Inc */
>> > +
>> > +#ifndef _IONIC_DEVLINK_H_
>> > +#define _IONIC_DEVLINK_H_
>> > +
>> > +#include <net/devlink.h>
>> > +
>> > +int ionic_devlink_register(struct ionic *ionic);
>> > +void ionic_devlink_unregister(struct ionic *ionic);
>> > +
>> > +#endif /* _IONIC_DEVLINK_H_ */
>> > -- 
>> > 2.17.1
>> > 
>