Messages in this thread | | | Date | Wed, 16 May 2018 18:21:09 +0530 | From | poza@codeauro ... | Subject | Re: [PATCH v16 8/9] PCI/DPC: Unify and plumb error handling into DPC |
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On 2018-05-16 16:22, Bjorn Helgaas wrote: > On Wed, May 16, 2018 at 01:46:25PM +0530, poza@codeaurora.org wrote: >> On 2018-05-16 05:26, Bjorn Helgaas wrote: >> > On Fri, May 11, 2018 at 05:22:08PM +0530, poza@codeaurora.org wrote: >> > > On 2018-05-11 16:13, Oza Pawandeep wrote: >> > > > DPC driver implements link_reset callback, and calls >> > > > pci_do_fatal_recovery(). >> > > > >> > > > Which follows standard path of ERR_FATAL recovery. >> > > > >> > > > Signed-off-by: Oza Pawandeep <poza@codeaurora.org> >> > > > >> > > > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h >> > > > index 5e8857a..6af7595 100644 >> > > > --- a/drivers/pci/pci.h >> > > > +++ b/drivers/pci/pci.h >> > > > @@ -354,7 +354,7 @@ static inline resource_size_t >> > > > pci_resource_alignment(struct pci_dev *dev, >> > > > void pci_enable_acs(struct pci_dev *dev); >> > > > >> > > > /* PCI error reporting and recovery */ >> > > > -void pcie_do_fatal_recovery(struct pci_dev *dev); >> > > > +void pcie_do_fatal_recovery(struct pci_dev *dev, u32 service); >> > > > void pcie_do_nonfatal_recovery(struct pci_dev *dev); >> > > > >> > > > bool pcie_wait_for_link(struct pci_dev *pdev, bool active); >> > > > diff --git a/drivers/pci/pcie/aer/aerdrv_core.c >> > > > b/drivers/pci/pcie/aer/aerdrv_core.c >> > > > index fdfc474..36e622d 100644 >> > > > --- a/drivers/pci/pcie/aer/aerdrv_core.c >> > > > +++ b/drivers/pci/pcie/aer/aerdrv_core.c >> > > > @@ -254,7 +254,7 @@ static void handle_error_source(struct pcie_device >> > > > *aerdev, >> > > > } else if (info->severity == AER_NONFATAL) >> > > > pcie_do_nonfatal_recovery(dev); >> > > > else if (info->severity == AER_FATAL) >> > > > - pcie_do_fatal_recovery(dev); >> > > > + pcie_do_fatal_recovery(dev, PCIE_PORT_SERVICE_AER); >> > > > } >> > > > >> > > > #ifdef CONFIG_ACPI_APEI_PCIEAER >> > > > @@ -321,7 +321,7 @@ static void aer_recover_work_func(struct work_struct >> > > > *work) >> > > > if (entry.severity == AER_NONFATAL) >> > > > pcie_do_nonfatal_recovery(pdev); >> > > > else if (entry.severity == AER_FATAL) >> > > > - pcie_do_fatal_recovery(pdev); >> > > > + pcie_do_fatal_recovery(pdev, PCIE_PORT_SERVICE_AER); >> > > > pci_dev_put(pdev); >> > > > } >> > > > } >> > > > diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c >> > > > index 80ec384..5680c13 100644 >> > > > --- a/drivers/pci/pcie/dpc.c >> > > > +++ b/drivers/pci/pcie/dpc.c >> > > > @@ -73,29 +73,31 @@ static void dpc_wait_link_inactive(struct dpc_dev >> > > > *dpc) >> > > > pcie_wait_for_link(pdev, false); >> > > > } >> > > > >> > > > -static void dpc_work(struct work_struct *work) >> > > > +static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev) >> > > > { >> > > > - struct dpc_dev *dpc = container_of(work, struct dpc_dev, work); >> > > > - struct pci_dev *dev, *temp, *pdev = dpc->dev->port; >> > > > - struct pci_bus *parent = pdev->subordinate; >> > > > - u16 cap = dpc->cap_pos, ctl; >> > > > - >> > > > - pci_lock_rescan_remove(); >> > > > - list_for_each_entry_safe_reverse(dev, temp, &parent->devices, >> > > > - bus_list) { >> > > > - pci_dev_get(dev); >> > > > - pci_dev_set_disconnected(dev, NULL); >> > > > - if (pci_has_subordinate(dev)) >> > > > - pci_walk_bus(dev->subordinate, >> > > > - pci_dev_set_disconnected, NULL); >> > > > - pci_stop_and_remove_bus_device(dev); >> > > > - pci_dev_put(dev); >> > > > - } >> > > > - pci_unlock_rescan_remove(); >> > > > - >> > > > + struct dpc_dev *dpc; >> > > > + struct pcie_device *pciedev; >> > > > + struct device *devdpc; >> > > > + u16 cap, ctl; >> > > > + >> > > > + /* >> > > > + * DPC disables the Link automatically in hardware, so it has >> > > > + * already been reset by the time we get here. >> > > > + */ >> > > > + >> > > > + devdpc = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC); >> > > > + pciedev = to_pcie_device(devdpc); >> > > > + dpc = get_service_data(pciedev); >> > > > + cap = dpc->cap_pos; >> > > > + >> > > > + /* >> > > > + * Waiting until the link is inactive, then clearing DPC >> > > > + * trigger status to allow the port to leave DPC. >> > > > + */ >> > > > dpc_wait_link_inactive(dpc); >> > > > + >> > > > if (dpc->rp_extensions && dpc_wait_rp_inactive(dpc)) >> > > > - return; >> > > > + return PCI_ERS_RESULT_DISCONNECT; >> > > > if (dpc->rp_extensions && dpc->rp_pio_status) { >> > > > pci_write_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_STATUS, >> > > > dpc->rp_pio_status); >> > > > @@ -108,6 +110,17 @@ static void dpc_work(struct work_struct *work) >> > > > pci_read_config_word(pdev, cap + PCI_EXP_DPC_CTL, &ctl); >> > > > pci_write_config_word(pdev, cap + PCI_EXP_DPC_CTL, >> > > > ctl | PCI_EXP_DPC_CTL_INT_EN); >> > > > + >> > > > + return PCI_ERS_RESULT_RECOVERED; >> > > > +} >> > > > + >> > > > +static void dpc_work(struct work_struct *work) >> > > > +{ >> > > > + struct dpc_dev *dpc = container_of(work, struct dpc_dev, work); >> > > > + struct pci_dev *pdev = dpc->dev->port; >> > > > + >> > > > + /* From DPC point of view error is always FATAL. */ >> > > > + pcie_do_fatal_recovery(pdev, PCIE_PORT_SERVICE_DPC); >> > > > } >> > > > >> > > > static void dpc_process_rp_pio_error(struct dpc_dev *dpc) >> > > > @@ -288,6 +301,7 @@ static struct pcie_port_service_driver dpcdriver = { >> > > > .service = PCIE_PORT_SERVICE_DPC, >> > > > .probe = dpc_probe, >> > > > .remove = dpc_remove, >> > > > + .reset_link = dpc_reset_link, >> > > > }; >> > > > >> > > > static int __init dpc_service_init(void) >> > > > diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c >> > > > index 33a16b1..29ff148 100644 >> > > > --- a/drivers/pci/pcie/err.c >> > > > +++ b/drivers/pci/pcie/err.c >> > > > @@ -185,7 +185,7 @@ static pci_ers_result_t default_reset_link(struct >> > > > pci_dev *dev) >> > > > return PCI_ERS_RESULT_RECOVERED; >> > > > } >> > > > >> > > > -static pci_ers_result_t reset_link(struct pci_dev *dev) >> > > > +static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service) >> > > > { >> > > > struct pci_dev *udev; >> > > > pci_ers_result_t status; >> > > > @@ -200,7 +200,7 @@ static pci_ers_result_t reset_link(struct pci_dev >> > > > *dev) >> > > > } >> > > > >> > > > /* Use the aer driver of the component firstly */ >> > > > - driver = pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER); >> > > > + driver = pcie_port_find_service(udev, service); >> > > > >> > > > if (driver && driver->reset_link) { >> > > > status = driver->reset_link(udev); >> > > > @@ -287,7 +287,7 @@ static pci_ers_result_t >> > > > broadcast_error_message(struct pci_dev *dev, >> > > > * followed by re-enumeration of devices. >> > > > */ >> > > > >> > > > -void pcie_do_fatal_recovery(struct pci_dev *dev) >> > > > +void pcie_do_fatal_recovery(struct pci_dev *dev, u32 service) >> > > > { >> > > > struct pci_dev *udev; >> > > > struct pci_bus *parent; >> > > > @@ -313,7 +313,7 @@ void pcie_do_fatal_recovery(struct pci_dev *dev) >> > > > pci_dev_put(pdev); >> > > > } >> > > > >> > > > - result = reset_link(udev); >> > > > + result = reset_link(udev, service); >> > > > >> > > > if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) { >> > > > /* >> > > > diff --git a/include/linux/aer.h b/include/linux/aer.h >> > > > index 8f87bbe..0c506fe 100644 >> > > > --- a/include/linux/aer.h >> > > > +++ b/include/linux/aer.h >> > > > @@ -14,6 +14,7 @@ >> > > > #define AER_NONFATAL 0 >> > > > #define AER_FATAL 1 >> > > > #define AER_CORRECTABLE 2 >> > > > +#define DPC_FATAL 4 >> > >> > I think DPC_FATAL can be 3, since these values are not used as a bit >> > mask. >> > >> > > > struct pci_dev; >> > > >> > > >> > > Hi Bjorn, >> > > >> > > >> > > I have addressed all the comments, and I hope we are heading towards >> > > closure. >> > > >> > > I just figure that pcie_do_fatal_recovery (which is getting >> > > executed for >> > > DPC as well) >> > > >> > > if (result == PCI_ERS_RESULT_RECOVERED) { >> > > if (pcie_wait_for_link(udev, true)) >> > > pci_rescan_bus(udev->bus); >> > > pci_info(dev, "Device recovery successful\n"); >> > > } >> > > >> > > I have to correct it to >> > > >> > > if (service==AER && result == PCI_ERS_RESULT_RECOVERED) { >> > > if (pcie_wait_for_link(udev, true)) >> > > pci_rescan_bus(udev->bus); >> > > pci_info(dev, "Device recovery successful\n"); >> > > } >> > >> > This patch is mostly a restructuring of DPC and doesn't really change >> > its >> > behavior. DPC didn't previously call pcie_wait_for_link() or >> > pci_rescan_bus(), so I agree that adding the "service==AER" test will >> > help preserve the existing DPC behavior. >> > >> > However, the rescan should happen with DPC *somewhere* and we should >> > clarify where that is. Maybe for now we only need a comment about where >> > that happens. Ideally, we could eventually converge this so the same >> > mechanism is used for AER and DPC, so we wouldn't need a test like >> > "service=AER". > > Please still add a comment here about why the rescan behavior is > different.
I am not sure if I understand this comment. AER and DPC will follow the same path. if (result == PCI_ERS_RESULT_RECOVERED) { if (pcie_wait_for_link(udev, true)) pci_rescan_bus(udev->bus); pci_info(dev, "Device recovery successful\n"); }
so the above code will execute for both AER and DPC. and before re-enumerating both will wait for link to become active.
Regards, Oza.
> >> I am sorry I pasted the wrong snippet. >> following needs to be fixed in v17. >> from: >> if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) { >> /* >> * If the error is reported by a bridge, we think this >> error >> * is related to the downstream link of the bridge, so >> we >> * do error recovery on all subordinates of the bridge >> instead >> * of the bridge and clear the error status of the >> bridge. >> */ >> pci_walk_bus(dev->subordinate, report_resume, >> &result_data); >> pci_cleanup_aer_uncorrect_error_status(dev); >> } >> >> >> to >> >> if (service==AER && dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) { >> /* >> * If the error is reported by a bridge, we think this >> error >> * is related to the downstream link of the bridge, so >> we >> * do error recovery on all subordinates of the bridge >> instead >> * of the bridge and clear the error status of the >> bridge. >> */ >> pci_walk_bus(dev->subordinate, report_resume, >> &result_data); >> pci_cleanup_aer_uncorrect_error_status(dev); >> } >> >> this is only needed in case of AER. > > Oh, I missed this before. It makes sense to clear the AER status > here, but why do we need to call report_resume()? We just called all > the driver .remove() methods and detached the drivers from the > devices. So I don't think report_resume() will do anything > ("dev->driver" should be NULL) except set the dev->error_state to > pci_channel_io_normal. We probably don't need that because we didn't > change error_state in this fatal error path. > >> by the way I can not find pci/oza-v16 branch when I cloned >> git clone >> https://kernel.googlesource.com/pub/scm/linux/kernel/git/helgaas/pci > > Sorry, I must have forgotten to push it. It's there now at > > > https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/log/?h=pci/oza-v16 > > I don't know anything about the googlesource mirror, so I don't know > when it will get there.
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