| Message ID | 20180226031911.18980.80488.stgit@mdrustad-mac04.local (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
From: Mark Rustad <mark.d.rustad@intel.com> Date: Sun, 25 Feb 2018 19:19:11 -0800 > diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c > index 677924ae0350..ddd44a9d93ec 100644 > --- a/drivers/pci/iov.c > +++ b/drivers/pci/iov.c > @@ -367,6 +367,54 @@ static void sriov_disable(struct pci_dev *dev) > pci_iov_set_numvfs(dev, 0); > } > > +/** > + * pci_sriov_disable - standard helper to disable SR-IOV > + * @dev:the PCI PF device whose VFs are to be disabled > + */ > +int pci_sriov_disable(struct pci_dev *dev) > +{ > + /* > + * If vfs are assigned we cannot shut down SR-IOV without causing > + * issues, so just leave the hardware available. > + */ > + if (pci_vfs_assigned(dev)) { > + pci_warn(&dev->dev, > + "Cannot disable SR-IOV while VFs are assigned - VFs will not be deallocated\n"); > + return -EPERM; > + } > + pci_disable_sriov(dev); > + return 0; > +} > + > +static int pci_sriov_enable(struct pci_dev *dev, int num_vfs) > +{ > + int rc; > + > + if (pci_num_vf(dev)) > + return -EINVAL; > + > + rc = pci_enable_sriov(dev, num_vfs); > + if (rc) { > + pci_warn(dev, "Failed to enable PCI sriov: %d\n", rc); > + return rc; > + } > + dev_info(dev, "SR-IOV enabled with %d VFs\n", num_vfs); > + return num_vfs; > +} I don't like these helpers on many different levels. The pci_num_vf() test in pci_sriov_enable() is redundant, the pci_enable_sriov() code path does that check and returns the same exact error code from sriov_enable(). Just call pci_enable_sriov() directly. The log message adds no value justifying an entirely new (and confusingly named) helper. If the log message is useful, add it to pci_enable_sriov(). Speaking of naming, is this stuff confusing or what? As a programmer what am I supposed to think when I consider what may be the difference between two interfaces, the only difference in naming is that two words are transposed? pci_enable_sriov() pci_sriov_enable() pci_disable_sriov() pci_sriov_disable() ?!?!?!?! As per pci_sriov_disable() explicitly, all it does different is check for vf assignment and return failure. If you want a little help that does that, name it appropriately. pci_disable_sriov_if_unassigned() So kill off pci_sriov_enable() helper completely, it is unnecessary, and rename the disable helper so that it says something meaningful to the reader. Thanks.
> On Feb 27, 2018, at 7:35 AM, David Miller <davem@davemloft.net> wrote: > > I don't like these helpers on many different levels. <snip much embarrassment> > So kill off pci_sriov_enable() helper completely, it is unnecessary, > and rename the disable helper so that it says something meaningful to > the reader. Yes. Once pointed out, I completely agree with your comments and wish that I had seen those things myself. > Thanks. V3 was junk, but your comments apply to V4 as well, so please ignore it. Thank you for your valuable review.
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 677924ae0350..ddd44a9d93ec 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -367,6 +367,54 @@ static void sriov_disable(struct pci_dev *dev) pci_iov_set_numvfs(dev, 0); } +/** + * pci_sriov_disable - standard helper to disable SR-IOV + * @dev:the PCI PF device whose VFs are to be disabled + */ +int pci_sriov_disable(struct pci_dev *dev) +{ + /* + * If vfs are assigned we cannot shut down SR-IOV without causing + * issues, so just leave the hardware available. + */ + if (pci_vfs_assigned(dev)) { + pci_warn(&dev->dev, + "Cannot disable SR-IOV while VFs are assigned - VFs will not be deallocated\n"); + return -EPERM; + } + pci_disable_sriov(dev); + return 0; +} + +static int pci_sriov_enable(struct pci_dev *dev, int num_vfs) +{ + int rc; + + if (pci_num_vf(dev)) + return -EINVAL; + + rc = pci_enable_sriov(dev, num_vfs); + if (rc) { + pci_warn(dev, "Failed to enable PCI sriov: %d\n", rc); + return rc; + } + dev_info(dev, "SR-IOV enabled with %d VFs\n", num_vfs); + return num_vfs; +} + +/** + * pci_sriov_configure - standard helper to configure SR-IOV + * @dev: the PCI PF device that is configuring SR-IOV + */ +int pci_sriov_configure(struct pci_dev *dev, int num_vfs) +{ + if (num_vfs) + return pci_sriov_enable(dev, num_vfs); + if (!pci_num_vf(dev)) + return -EINVAL; + return pci_sriov_disable(dev); +} + static int sriov_init(struct pci_dev *dev, int pos) { int i, bar64; diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index 48d4d1cf1cb6..37e353c4f8b4 100644 --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -584,6 +584,7 @@ static void virtio_pci_remove(struct pci_dev *pci_dev) else virtio_pci_modern_remove(vp_dev); + pci_sriov_disable(pci_dev); pci_disable_device(pci_dev); put_device(dev); } @@ -596,6 +597,7 @@ static struct pci_driver virtio_pci_driver = { #ifdef CONFIG_PM_SLEEP .driver.pm = &virtio_pci_pm_ops, #endif + .sriov_configure = pci_sriov_configure, }; module_pci_driver(virtio_pci_driver); diff --git a/include/linux/pci.h b/include/linux/pci.h index 024a1beda008..ef6b359afefd 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1947,6 +1947,8 @@ int pci_iov_virtfn_devfn(struct pci_dev *dev, int id); int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn); void pci_disable_sriov(struct pci_dev *dev); +int pci_sriov_disable(struct pci_dev *dev); +int pci_sriov_configure(struct pci_dev *dev, int num_vfs); int pci_iov_add_virtfn(struct pci_dev *dev, int id); void pci_iov_remove_virtfn(struct pci_dev *dev, int id); int pci_num_vf(struct pci_dev *dev); @@ -1973,6 +1975,14 @@ static inline int pci_iov_add_virtfn(struct pci_dev *dev, int id) static inline void pci_iov_remove_virtfn(struct pci_dev *dev, int id) { } static inline void pci_disable_sriov(struct pci_dev *dev) { } +static inline int pci_sriov_disable(struct pci_dev *dev) +{ + return -ENODEV; +} +static inline int pci_sriov_configure(struct pci_dev *dev, int num_vfs) +{ + return -ENODEV; +} static inline int pci_num_vf(struct pci_dev *dev) { return 0; } static inline int pci_vfs_assigned(struct pci_dev *dev) { return 0; }