From: Bjorn Helgaas <helgaas@kernel.org>
To: Sean V Kelley <sean.v.kelley@intel.com>
Cc: bhelgaas@google.com, Jonathan.Cameron@huawei.com,
xerces.zhao@gmail.com, rafael.j.wysocki@intel.com,
ashok.raj@intel.com, tony.luck@intel.com,
sathyanarayanan.kuppuswamy@intel.com, qiuxu.zhuo@intel.com,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>
Subject: Re: [PATCH v12 07/15] PCI/ERR: Use "bridge" for clarity in pcie_do_recovery()
Date: Wed, 2 Dec 2020 17:18:59 -0600 [thread overview]
Message-ID: <20201202231859.GA1484005@bjorn-Precision-5520> (raw)
In-Reply-To: <20201121001036.8560-8-sean.v.kelley@intel.com>
On Fri, Nov 20, 2020 at 04:10:28PM -0800, Sean V Kelley wrote:
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index 7a5af873d8bc..46a5b84f8842 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -151,24 +151,27 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_ers_result_t (*reset_subordinates)(struct pci_dev *pdev))
> {
> int type = pci_pcie_type(dev);
> - pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
> + struct pci_dev *bridge;
> struct pci_bus *bus;
> + pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
>
> /*
> - * Error recovery runs on all subordinates of the first downstream port.
> - * If the downstream port detected the error, it is cleared at the end.
> + * Error recovery runs on all subordinates of the bridge. If the
> + * bridge detected the error, it is cleared at the end.
> */
> if (!(type == PCI_EXP_TYPE_ROOT_PORT ||
> type == PCI_EXP_TYPE_DOWNSTREAM))
> - dev = pci_upstream_bridge(dev);
> - bus = dev->subordinate;
> + bridge = pci_upstream_bridge(dev);
> + else
> + bridge = dev;
I think there's a bug here even before your series. We started with:
pcie_do_recovery(struct pci_dev *dev, ..., pci_ers_result_t (*reset_link)())
{
if (!(pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM))
dev = dev->bus->self;
...
reset_link(dev);
so if we called pcie_do_recovery() with an Endpoint, we set "dev" to
the upstream bridge, either a Root Port or a Switch Downstream Port,
which we then pass on to reset_link(). For native AER and APEI,
that's aer_root_reset(), which assumes it gets a Root Port.
If we pass a Switch Downstream Port, aer_root_reset() writes to the
*switch port's* PCI_ERR_ROOT_COMMAND and PCI_ERR_ROOT_STATUS, which
are reserved since it's not a Root Port or an RCEC.
The writes probably don't *break* anything since those registers are
reserved, but they also don't disable the interrupt or clear the Root
Error Status.
Bjorn
next prev parent reply other threads:[~2020-12-02 23:19 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-21 0:10 [PATCH v12 00/15] Add RCEC handling to PCI/AER Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 01/15] AER: aer_root_reset() non-native handling Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 02/15] PCI/RCEC: Bind RCEC devices to the Root Port driver Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 03/15] PCI/RCEC: Cache RCEC capabilities in pci_init_capabilities() Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 04/15] PCI/ERR: Rename reset_link() to reset_subordinates() Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 05/15] PCI/ERR: Simplify by using pci_upstream_bridge() Sean V Kelley
2020-12-03 18:45 ` Kelley, Sean V
2020-12-03 22:25 ` Bjorn Helgaas
2020-11-21 0:10 ` [PATCH v12 06/15] PCI/ERR: Simplify by computing pci_pcie_type() once Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 07/15] PCI/ERR: Use "bridge" for clarity in pcie_do_recovery() Sean V Kelley
2020-12-02 23:18 ` Bjorn Helgaas [this message]
2020-11-21 0:10 ` [PATCH v12 08/15] PCI/ERR: Avoid negated conditional for clarity Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 09/15] PCI/ERR: Add pci_walk_bridge() to pcie_do_recovery() Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 10/15] PCI/ERR: Limit AER resets in pcie_do_recovery() Sean V Kelley
2020-11-23 23:28 ` Bjorn Helgaas
2020-11-23 23:57 ` Kelley, Sean V
2020-11-24 17:17 ` Bjorn Helgaas
2020-11-30 19:54 ` Kelley, Sean V
2020-12-01 0:25 ` Bjorn Helgaas
2020-12-01 1:09 ` Kuppuswamy, Sathyanarayanan
2020-12-01 1:13 ` Kelley, Sean V
2020-12-02 20:53 ` Kelley, Sean V
2020-12-02 21:27 ` Bjorn Helgaas
2020-12-02 22:54 ` Kelley, Sean V
2020-11-21 0:10 ` [PATCH v12 11/15] PCI/RCEC: Add pcie_link_rcec() to associate RCiEPs Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 12/15] PCI/RCEC: Add RCiEP's linked RCEC to AER/ERR Sean V Kelley
2020-12-02 23:44 ` Bjorn Helgaas
2020-12-03 0:51 ` Kelley, Sean V
2020-12-04 0:01 ` Bjorn Helgaas
2020-12-04 17:17 ` Kelley, Sean V
2020-12-04 17:24 ` Bjorn Helgaas
2020-12-05 21:30 ` Bjorn Helgaas
2020-12-07 17:23 ` Kelley, Sean V
2020-11-21 0:10 ` [PATCH v12 13/15] PCI/AER: Add pcie_walk_rcec() to RCEC AER handling Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 14/15] PCI/PME: Add pcie_walk_rcec() to RCEC PME handling Sean V Kelley
2020-11-21 0:10 ` [PATCH v12 15/15] PCI/AER: Add RCEC AER error injection support Sean V Kelley
2020-11-21 4:26 ` [PATCH v12 00/15] Add RCEC handling to PCI/AER Bjorn Helgaas
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