| Message ID | 1392173573-59844-6-git-send-email-wangyijing@huawei.com |
|---|---|
| State | Changes Requested |
| Headers | show |
Hi Yijing, On 02/12/2014 10:52 AM, Yijing Wang wrote: > Pci_dummy_ops does nothing when we use it to read/write > pci_device. So we can isolate pci device by replace its > bus pci_ops by pci_dummy_ops. This is preparation for > the later patch. > > Signed-off-by: Yijing Wang <wangyijing@huawei.com> > --- > drivers/pci/pci.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/pci.h | 4 +++ > 2 files changed, 66 insertions(+), 0 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index af34057..283e82e 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -2226,6 +2226,68 @@ bool pci_serial_number_changed(struct pci_dev *pdev) > } > EXPORT_SYMBOL(pci_serial_number_changed); > > +static int pci_dummy_read(struct pci_bus *bus, unsigned int devfn, > + int where, int size, u32 *val) > +{ > + return PCIBIOS_DEVICE_NOT_FOUND; > +} > + > +static int pci_dummy_write(struct pci_bus *bus, unsigned int devfn, > + int reg, int size, u32 val) > +{ > + return PCIBIOS_DEVICE_NOT_FOUND; > +} > + > +static struct pci_ops pci_dummy_ops = { > + .read = pci_dummy_read, > + .write = pci_dummy_write, > +}; > + > +static DEFINE_SPINLOCK(pci_freeze_lock); > +/** > + * pci_bus_freeze_device - freeze pci bus to access pci device > + * @bus: the pci bus to freeze > + * > + * Replace pci bus ops by pci_dummy_ops, protect system from > + * accessing pci devices. > + */ > +void pci_bus_freeze_device(struct pci_bus *bus) > +{ > + struct pci_ops *ops; > + unsigned long flags; > + > + spin_lock_irqsave(&pci_freeze_lock, flags); > + if (bus->is_frozen) > + goto out; > + bus->is_frozen = 1; > + ops = pci_bus_set_ops(bus, &pci_dummy_ops); > + bus->save_ops = ops; > +out: > + spin_unlock_irqrestore(&pci_freeze_lock, flags); > +} > + > +/** > + * pci_bus_unfreeze_device - unfreeze pci bus to acess pci devices > + * @bus: the pci bus to unfreeze > + * > + * Restore pci bus original ops, so pci bus can access > + * pci devices normally. > + */ > +void pci_bus_unfreeze_device(struct pci_bus *bus) > +{ > + unsigned long flags; > + > + BUG_ON(!bus->save_ops); > + spin_lock_irqsave(&pci_freeze_lock, flags); > + if (!bus->is_frozen) > + goto out; It seems that the BUG_ON() should placed here, otherwise it will be triggered if we try to unfreeze the same bus multiply. Regards, Gu > + pci_bus_set_ops(bus, bus->save_ops); > + bus->save_ops = NULL; > + bus->is_frozen = 0; > +out: > + spin_unlock_irqrestore(&pci_freeze_lock, flags); > +} > + > /** > * pci_configure_ari - enable or disable ARI forwarding > * @dev: the PCI device > diff --git a/include/linux/pci.h b/include/linux/pci.h > index d60c0b6..e3dd4ea 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -442,6 +442,7 @@ struct pci_bus { > struct resource busn_res; /* bus numbers routed to this bus */ > > struct pci_ops *ops; /* configuration access functions */ > + struct pci_ops *save_ops; /* save configuration access functions */ > struct msi_chip *msi; /* MSI controller */ > void *sysdata; /* hook for sys-specific extension */ > struct proc_dir_entry *procdir; /* directory entry in /proc/bus/pci */ > @@ -460,6 +461,7 @@ struct pci_bus { > struct bin_attribute *legacy_io; /* legacy I/O for this bus */ > struct bin_attribute *legacy_mem; /* legacy mem */ > unsigned int is_added:1; > + unsigned int is_frozen:1; > }; > > #define pci_bus_b(n) list_entry(n, struct pci_bus, node) > @@ -1026,6 +1028,8 @@ ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf); > ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf); > > bool pci_serial_number_changed(struct pci_dev *pdev); > +void pci_bus_freeze_device(struct pci_bus *bus); > +void pci_bus_unfreeze_device(struct pci_bus *bus); > > /* Helper functions for low-level code (drivers/pci/setup-[bus,res].c) */ > resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx); -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
>> +void pci_bus_unfreeze_device(struct pci_bus *bus) >> +{ >> + unsigned long flags; >> + >> + BUG_ON(!bus->save_ops); >> + spin_lock_irqsave(&pci_freeze_lock, flags); >> + if (!bus->is_frozen) >> + goto out; > > It seems that the BUG_ON() should placed here, otherwise it will be > triggered if we try to unfreeze the same bus multiply. > Oh, right, I should move it down, thanks for the good catch. > >> + pci_bus_set_ops(bus, bus->save_ops); >> + bus->save_ops = NULL; >> + bus->is_frozen = 0; >> +out: >> + spin_unlock_irqrestore(&pci_freeze_lock, flags); >> +} >> + >> /** >> * pci_configure_ari - enable or disable ARI forwarding >> * @dev: the PCI device >> diff --git a/include/linux/pci.h b/include/linux/pci.h >> index d60c0b6..e3dd4ea 100644 >> --- a/include/linux/pci.h >> +++ b/include/linux/pci.h >> @@ -442,6 +442,7 @@ struct pci_bus { >> struct resource busn_res; /* bus numbers routed to this bus */ >> >> struct pci_ops *ops; /* configuration access functions */ >> + struct pci_ops *save_ops; /* save configuration access functions */ >> struct msi_chip *msi; /* MSI controller */ >> void *sysdata; /* hook for sys-specific extension */ >> struct proc_dir_entry *procdir; /* directory entry in /proc/bus/pci */ >> @@ -460,6 +461,7 @@ struct pci_bus { >> struct bin_attribute *legacy_io; /* legacy I/O for this bus */ >> struct bin_attribute *legacy_mem; /* legacy mem */ >> unsigned int is_added:1; >> + unsigned int is_frozen:1; >> }; >> >> #define pci_bus_b(n) list_entry(n, struct pci_bus, node) >> @@ -1026,6 +1028,8 @@ ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf); >> ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf); >> >> bool pci_serial_number_changed(struct pci_dev *pdev); >> +void pci_bus_freeze_device(struct pci_bus *bus); >> +void pci_bus_unfreeze_device(struct pci_bus *bus); >> >> /* Helper functions for low-level code (drivers/pci/setup-[bus,res].c) */ >> resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx); > > > > . >
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index af34057..283e82e 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2226,6 +2226,68 @@ bool pci_serial_number_changed(struct pci_dev *pdev) } EXPORT_SYMBOL(pci_serial_number_changed); +static int pci_dummy_read(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 *val) +{ + return PCIBIOS_DEVICE_NOT_FOUND; +} + +static int pci_dummy_write(struct pci_bus *bus, unsigned int devfn, + int reg, int size, u32 val) +{ + return PCIBIOS_DEVICE_NOT_FOUND; +} + +static struct pci_ops pci_dummy_ops = { + .read = pci_dummy_read, + .write = pci_dummy_write, +}; + +static DEFINE_SPINLOCK(pci_freeze_lock); +/** + * pci_bus_freeze_device - freeze pci bus to access pci device + * @bus: the pci bus to freeze + * + * Replace pci bus ops by pci_dummy_ops, protect system from + * accessing pci devices. + */ +void pci_bus_freeze_device(struct pci_bus *bus) +{ + struct pci_ops *ops; + unsigned long flags; + + spin_lock_irqsave(&pci_freeze_lock, flags); + if (bus->is_frozen) + goto out; + bus->is_frozen = 1; + ops = pci_bus_set_ops(bus, &pci_dummy_ops); + bus->save_ops = ops; +out: + spin_unlock_irqrestore(&pci_freeze_lock, flags); +} + +/** + * pci_bus_unfreeze_device - unfreeze pci bus to acess pci devices + * @bus: the pci bus to unfreeze + * + * Restore pci bus original ops, so pci bus can access + * pci devices normally. + */ +void pci_bus_unfreeze_device(struct pci_bus *bus) +{ + unsigned long flags; + + BUG_ON(!bus->save_ops); + spin_lock_irqsave(&pci_freeze_lock, flags); + if (!bus->is_frozen) + goto out; + pci_bus_set_ops(bus, bus->save_ops); + bus->save_ops = NULL; + bus->is_frozen = 0; +out: + spin_unlock_irqrestore(&pci_freeze_lock, flags); +} + /** * pci_configure_ari - enable or disable ARI forwarding * @dev: the PCI device diff --git a/include/linux/pci.h b/include/linux/pci.h index d60c0b6..e3dd4ea 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -442,6 +442,7 @@ struct pci_bus { struct resource busn_res; /* bus numbers routed to this bus */ struct pci_ops *ops; /* configuration access functions */ + struct pci_ops *save_ops; /* save configuration access functions */ struct msi_chip *msi; /* MSI controller */ void *sysdata; /* hook for sys-specific extension */ struct proc_dir_entry *procdir; /* directory entry in /proc/bus/pci */ @@ -460,6 +461,7 @@ struct pci_bus { struct bin_attribute *legacy_io; /* legacy I/O for this bus */ struct bin_attribute *legacy_mem; /* legacy mem */ unsigned int is_added:1; + unsigned int is_frozen:1; }; #define pci_bus_b(n) list_entry(n, struct pci_bus, node) @@ -1026,6 +1028,8 @@ ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf); ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf); bool pci_serial_number_changed(struct pci_dev *pdev); +void pci_bus_freeze_device(struct pci_bus *bus); +void pci_bus_unfreeze_device(struct pci_bus *bus); /* Helper functions for low-level code (drivers/pci/setup-[bus,res].c) */ resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx);
Pci_dummy_ops does nothing when we use it to read/write pci_device. So we can isolate pci device by replace its bus pci_ops by pci_dummy_ops. This is preparation for the later patch. Signed-off-by: Yijing Wang <wangyijing@huawei.com> --- drivers/pci/pci.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/pci.h | 4 +++ 2 files changed, 66 insertions(+), 0 deletions(-)