From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZqCvv/I17gGqUkGebXQdsA3sFbjPRLs6Ys4L1sg6zlr5JjbQPxw/PqH1YRnLMcBn8lvnajf ARC-Seal: i=1; a=rsa-sha256; t=1526467959; cv=none; d=google.com; s=arc-20160816; b=sWK2AIwTncnPRjzwT2T5io7aVVOYJ7yrD1s2ArFgK9ld8Y5AWWbYN9ogfd1a5Kjz1f SnLVYl4T1X1wP8EefwAB8t8BspJgarv6Jy6THunzwZUzBAzHzyl/zPKZDKrrWTleuLPm 7h58Zl3g/9EtoQlhZ6lZUv68qWw59BB8uDjEgEFXHOcPOt1v9KggU1hBpEnMWaycFKN/ J8lbYpR6cJAlIbG+fhR8VbKZTN2/pKx8i6APw44+9sCA7gUymUnDxRxsPv4YxppIcDem nlpMRiBdxuv07cS9K/IPNEDnrxBsCHOMgUp0PaW2xhx8c3bK5surtDppfmnXIbxY4kXb i+Pw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature :arc-authentication-results; bh=HY1CorqO79x6Qr+2IZG00KFbg0THsZ7KD+ySmcpVyyg=; b=N0hhPUrlQBfM4YE/jB6W0tkl2VAUB7JbsmuNw/gVb8LROshFVhDygPeZmcG3b1nZFP U9kFMoc1tIULEKGIKL4mv6WZG5OKFhmqk47W4T9z6xXgiUDcf1P/eijNm79p1YXLoKS6 V0P3o4GDZPpeMA+OWQegC0mxQyO+ESkKjCvQCzD8xe3dkoPfNPR2x8Pus6qoEYcwBAUe 5Vd2olhsfSZHIFsi8SkiPqhgeZXYzlJH+15MJ07AsOCC8I/F4AH1PjACDUqh5Efw/b6X AcoEunZAwmuwHhpSyRmVsagtX98dx5Jq2RCNqZSe3XL+LusIVQIw4lQmorbrOyhObL/m 5ITg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=EMmLNoRb; spf=pass (google.com: domain of helgaas@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=helgaas@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=EMmLNoRb; spf=pass (google.com: domain of helgaas@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=helgaas@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Date: Wed, 16 May 2018 05:52:36 -0500 From: Bjorn Helgaas To: poza@codeaurora.org Cc: Bjorn Helgaas , Philippe Ombredanne , Thomas Gleixner , Greg Kroah-Hartman , Kate Stewart , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Dongdong Liu , Keith Busch , Wei Zhang , Sinan Kaya , Timur Tabi Subject: Re: [PATCH v16 8/9] PCI/DPC: Unify and plumb error handling into DPC Message-ID: <20180516105236.GA217390@bhelgaas-glaptop.roam.corp.google.com> References: <1526035408-31328-1-git-send-email-poza@codeaurora.org> <1526035408-31328-9-git-send-email-poza@codeaurora.org> <20180515235632.GB11156@bhelgaas-glaptop.roam.corp.google.com> <2ca65f6b38668cfcf553833409ee38e3@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2ca65f6b38668cfcf553833409ee38e3@codeaurora.org> User-Agent: Mutt/1.9.2 (2017-12-15) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1600164111312988494?= X-GMAIL-MSGID: =?utf-8?q?1600617666396468199?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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 > > > > > > > > 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 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.