Re: [PATCH v4 4/8] PCI: replace pci_dev::driver usage that gets the driver name

Bjorn Helgaas
2021-09-28T17:18:02Z

[+to Oliver, Russell for eeh_driver_name() question below]

On Mon, Sep 27, 2021 at 10:43:22PM +0200, Uwe Kleine-König wrote:
> From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
>
> struct pci_dev::driver holds (apart from a constant offset) the same
> data as struct pci_dev::dev->driver. With the goal to remove struct
> pci_dev::driver to get rid of data duplication replace getting the
> driver name by dev_driver_string() which implicitly makes use of struct
> pci_dev::dev->driver.

When you repost to fix the build issue, can you capitalize the subject
line to match the other?

Also, would you mind using "pci_dev.driver" instead of
"pci_dev::driver"? AFAIK, the "::" operator is not actually part of
C, so I think it's more confusing than useful.

> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
> arch/powerpc/include/asm/ppc-pci.h | 9 ++++++++-
> drivers/bcma/host_pci.c | 7 ++++---
> drivers/crypto/hisilicon/qm.c | 2 +-
> drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c | 2 +-
> drivers/net/ethernet/marvell/prestera/prestera_pci.c | 2 +-
> drivers/net/ethernet/mellanox/mlxsw/pci.c | 2 +-
> drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c | 2 +-
> drivers/ssb/pcihost_wrapper.c | 8 +++++---
> 8 files changed, 22 insertions(+), 12 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/ppc-pci.h b/arch/powerpc/include/asm/ppc-pci.h
> index 2b9edbf6e929..e8f1795a2acf 100644
> --- a/arch/powerpc/include/asm/ppc-pci.h
> +++ b/arch/powerpc/include/asm/ppc-pci.h
> @@ -57,7 +57,14 @@ void eeh_sysfs_remove_device(struct pci_dev *pdev);
>
> static inline const char *eeh_driver_name(struct pci_dev *pdev)
> {
> - return (pdev && pdev->driver) ? pdev->driver->name : "<null>";
> + if (pdev) {
> + const char *drvstr = dev_driver_string(&pdev->dev);
> +
> + if (strcmp(drvstr, ""))
> + return drvstr;
> + }
> +
> + return "<null>";

Can we just do this?

if (pdev)
return dev_driver_string(&pdev->dev);

return "<null>";

I think it's more complicated than it's worth to include a strcmp().
It's possible this will change those error messages about "Might be
infinite loop in %s driver", but that doesn't seem like a huge deal.

I moved Oliver to "to:" and added Russell in case they object.

> }
>
> #endif /* CONFIG_EEH */
> diff --git a/drivers/bcma/host_pci.c b/drivers/bcma/host_pci.c
> index 69c10a7b7c61..0973022d4b13 100644
> --- a/drivers/bcma/host_pci.c
> +++ b/drivers/bcma/host_pci.c
> @@ -175,9 +175,10 @@ static int bcma_host_pci_probe(struct pci_dev *dev,
> if (err)
> goto err_kfree_bus;
>
> - name = dev_name(&dev->dev);
> - if (dev->driver && dev->driver->name)
> - name = dev->driver->name;
> + name = dev_driver_string(&dev->dev);
> + if (!strcmp(name, ""))
> + name = dev_name(&dev->dev);
> err = pci_request_regions(dev, name);

Again seems more complicated than it's worth to me. This is in the
driver's .probe() method, so really_probe() has already set
"dev->driver = drv", which means dev->driver is always set to
&bcma_pci_bridge_driver here, and bcma_pci_bridge_driver.name is
always "bcma-pci-bridge".

Almost all callers of pci_request_regions() just hardcode the driver
name or use a DRV_NAME #define

So I think we should just do:

err = pci_request_regions(dev, "bcma-pci-bridge");

> if (err)
> goto err_pci_disable;
> diff --git a/drivers/crypto/hisilicon/qm.c b/drivers/crypto/hisilicon/qm.c
> index 369562d34d66..8f361e54e524 100644
> --- a/drivers/crypto/hisilicon/qm.c
> +++ b/drivers/crypto/hisilicon/qm.c
> @@ -3085,7 +3085,7 @@ static int qm_alloc_uacce(struct hisi_qm *qm)
> };
> int ret;
>
> - ret = strscpy(interface.name, pdev->driver->name,
> + ret = strscpy(interface.name, dev_driver_string(&pdev->dev),
> sizeof(interface.name));
> if (ret < 0)
> return -ENAMETOOLONG;
> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
> index 7ea511d59e91..f279edfce3f1 100644
> --- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
> @@ -606,7 +606,7 @@ static void hns3_get_drvinfo(struct net_device *netdev,
> return;
> }
>
> - strncpy(drvinfo->driver, h->pdev->driver->name,
> + strncpy(drvinfo->driver, dev_driver_string(&h->pdev->dev),
> sizeof(drvinfo->driver));
> drvinfo->driver[sizeof(drvinfo->driver) - 1] = '\0';
>
> diff --git a/drivers/net/ethernet/marvell/prestera/prestera_pci.c b/drivers/net/ethernet/marvell/prestera/prestera_pci.c
> index a250d394da38..a8f007f6dad2 100644
> --- a/drivers/net/ethernet/marvell/prestera/prestera_pci.c
> +++ b/drivers/net/ethernet/marvell/prestera/prestera_pci.c
> @@ -720,7 +720,7 @@ static int prestera_fw_load(struct prestera_fw *fw)
> static int prestera_pci_probe(struct pci_dev *pdev,
> const struct pci_device_id *id)
> {
> - const char *driver_name = pdev->driver->name;
> + const char *driver_name = dev_driver_string(&pdev->dev);
> struct prestera_fw *fw;
> int err;
>
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci.c b/drivers/net/ethernet/mellanox/mlxsw/pci.c
> index 13b0259f7ea6..8f306364f7bf 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/pci.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/pci.c
> @@ -1876,7 +1876,7 @@ static void mlxsw_pci_cmd_fini(struct mlxsw_pci *mlxsw_pci)
>
> static int mlxsw_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> {
> - const char *driver_name = pdev->driver->name;
> + const char *driver_name = dev_driver_string(&pdev->dev);
> struct mlxsw_pci *mlxsw_pci;
> int err;
>
> diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c b/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c
> index 0685ece1f155..23dfb599c828 100644
> --- a/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c
> +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c
> @@ -202,7 +202,7 @@ nfp_get_drvinfo(struct nfp_app *app, struct pci_dev *pdev,
> {
> char nsp_version[ETHTOOL_FWVERS_LEN] = {};
>
> - strlcpy(drvinfo->driver, pdev->driver->name, sizeof(drvinfo->driver));
> + strlcpy(drvinfo->driver, dev_driver_string(&pdev->dev), sizeof(drvinfo->driver));
> nfp_net_get_nspinfo(app, nsp_version);
> snprintf(drvinfo->fw_version, sizeof(drvinfo->fw_version),
> "%s %s %s %s", vnic_version, nsp_version,
> diff --git a/drivers/ssb/pcihost_wrapper.c b/drivers/ssb/pcihost_wrapper.c
> index 410215c16920..4938ed5cfae5 100644
> --- a/drivers/ssb/pcihost_wrapper.c
> +++ b/drivers/ssb/pcihost_wrapper.c
> @@ -78,9 +78,11 @@ static int ssb_pcihost_probe(struct pci_dev *dev,
> err = pci_enable_device(dev);
> if (err)
> goto err_kfree_ssb;
> - name = dev_name(&dev->dev);
> - if (dev->driver && dev->driver->name)
> - name = dev->driver->name;
> +
> + name = dev_driver_string(&dev->dev);
> + if (*name == '\0')
> + name = dev_name(&dev->dev);
> +
> err = pci_request_regions(dev, name);

Also seems like more trouble than it's worth. This one is a little
strange but is always called for either b43_pci_bridge_driver or
b44_pci_driver, both of which have .name set, so I think we should
simply do:

err = pci_request_regions(dev, dev_driver_string(&dev->dev));

> if (err)
> goto err_pci_disable;
> --
> 2.30.2
>