On Wed, 2024-06-05 at 16:11 -0500, Bjorn Helgaas wrote:
> On Wed, Jun 05, 2024 at 10:15:59AM +0200, Philipp Stanner wrote:
> > The bit describing whether the PCI device is currently enabled is
> > stored
> > in struct pci_devres. Besides this struct being subject of a
> > cleanup
> > process, struct pci_device is in general the right place to store
> > this
> > information, since it is not devres-specific.
> >
> > Move the 'enabled' boolean bit to struct pci_dev.
>
> I think this (and the similar 'pinned' patch) appeared in v6.
Yes. This patch and its brothers serve to remove members from
struct pci_devres step by step, so it can ultimately be removed, so
that we won't have a generic devres struct anymore, but actual
resource-specific structs.
>
> It sounds plausible to have this in struct pci_dev, but it's
> confusing
> to have both:
>
> pci_dev.enabled
> pci_dev.enable_cnt, used by pci_is_enabled()
>
> I haven't looked hard enough to see whether both are required. If
> they are, I think we should rename "enabled" to something descriptive
> enough to make it obviously different from "enable_cnt".
I took a look at it and I think we can actually drop "enabled" and use
"enable_cnt" for everything. That would even simplify things more, I'd
say.
Let me provide that in v8.
P.
>
> > Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx>
> > ---
> > drivers/pci/devres.c | 11 ++++-------
> > drivers/pci/pci.c | 17 ++++++++++-------
> > drivers/pci/pci.h | 1 -
> > include/linux/pci.h | 1 +
> > 4 files changed, 15 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
> > index 572a4e193879..ea590caf8995 100644
> > --- a/drivers/pci/devres.c
> > +++ b/drivers/pci/devres.c
> > @@ -398,7 +398,7 @@ static void pcim_release(struct device *gendev,
> > void *res)
> > if (this->restore_intx)
> > pci_intx(dev, this->orig_intx);
> >
> > - if (this->enabled && !this->pinned)
> > + if (!this->pinned)
> > pci_disable_device(dev);
> > }
> >
> > @@ -441,14 +441,11 @@ int pcim_enable_device(struct pci_dev *pdev)
> > dr = get_pci_dr(pdev);
> > if (unlikely(!dr))
> > return -ENOMEM;
> > - if (dr->enabled)
> > - return 0;
> >
> > rc = pci_enable_device(pdev);
> > - if (!rc) {
> > + if (!rc)
> > pdev->is_managed = 1;
> > - dr->enabled = 1;
> > - }
> > +
> > return rc;
> > }
> > EXPORT_SYMBOL(pcim_enable_device);
> > @@ -466,7 +463,7 @@ void pcim_pin_device(struct pci_dev *pdev)
> > struct pci_devres *dr;
> >
> > dr = find_pci_dr(pdev);
> > - WARN_ON(!dr || !dr->enabled);
> > + WARN_ON(!dr || !pdev->enabled);
> > if (dr)
> > dr->pinned = 1;
> > }
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 8dd711b9a291..04accdfab7ce 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -2011,6 +2011,9 @@ static int do_pci_enable_device(struct
> > pci_dev *dev, int bars)
> > u16 cmd;
> > u8 pin;
> >
> > + if (dev->enabled)
> > + return 0;
> > +
> > err = pci_set_power_state(dev, PCI_D0);
> > if (err < 0 && err != -EIO)
> > return err;
> > @@ -2025,7 +2028,7 @@ static int do_pci_enable_device(struct
> > pci_dev *dev, int bars)
> > pci_fixup_device(pci_fixup_enable, dev);
> >
> > if (dev->msi_enabled || dev->msix_enabled)
> > - return 0;
> > + goto success_out;
> >
> > pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
> > if (pin) {
> > @@ -2035,6 +2038,8 @@ static int do_pci_enable_device(struct
> > pci_dev *dev, int bars)
> > cmd &
> > ~PCI_COMMAND_INTX_DISABLE);
> > }
> >
> > +success_out:
> > + dev->enabled = true;
> > return 0;
> > }
> >
> > @@ -2193,6 +2198,9 @@ static void do_pci_disable_device(struct
> > pci_dev *dev)
> > {
> > u16 pci_command;
> >
> > + if (!dev->enabled)
> > + return;
> > +
> > pci_read_config_word(dev, PCI_COMMAND, &pci_command);
> > if (pci_command & PCI_COMMAND_MASTER) {
> > pci_command &= ~PCI_COMMAND_MASTER;
> > @@ -2200,6 +2208,7 @@ static void do_pci_disable_device(struct
> > pci_dev *dev)
> > }
> >
> > pcibios_disable_device(dev);
> > + dev->enabled = false;
> > }
> >
> > /**
> > @@ -2227,12 +2236,6 @@ void pci_disable_enabled_device(struct
> > pci_dev *dev)
> > */
> > void pci_disable_device(struct pci_dev *dev)
> > {
> > - struct pci_devres *dr;
> > -
> > - dr = find_pci_dr(dev);
> > - if (dr)
> > - dr->enabled = 0;
> > -
> > dev_WARN_ONCE(&dev->dev, atomic_read(&dev->enable_cnt) <=
> > 0,
> > "disabling already-disabled device");
> >
> > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> > index 9fd50bc99e6b..e223e0f7dada 100644
> > --- a/drivers/pci/pci.h
> > +++ b/drivers/pci/pci.h
> > @@ -823,7 +823,6 @@ static inline pci_power_t
> > mid_pci_get_power_state(struct pci_dev *pdev)
> > * then remove them from here.
> > */
> > struct pci_devres {
> > - unsigned int enabled:1;
> > unsigned int pinned:1;
> > unsigned int orig_intx:1;
> > unsigned int restore_intx:1;
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index 16493426a04f..110548f00b3b 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -367,6 +367,7 @@ struct pci_dev {
> > this is D0-D3, D0 being
> > fully
> > functional, and D3 being
> > off. */
> > u8 pm_cap; /* PM capability offset */
> > + unsigned int enabled:1; /* Whether this dev is
> > enabled */
> > unsigned int imm_ready:1; /* Supports Immediate
> > Readiness */
> > unsigned int pme_support:5; /* Bitmask of states from
> > which PME#
> > can be generated */
> > --
> > 2.45.0
> >
>
