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Message-Id: <1514370022-4431-3-git-send-email-poza@codeaurora.org> Date: Wed, 27 Dec 2017 15:50:20 +0530 From: Oza Pawandeep <poza@...eaurora.org> To: Bjorn Helgaas <bhelgaas@...gle.com>, Philippe Ombredanne <pombredanne@...b.com>, Thomas Gleixner <tglx@...utronix.de>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Kate Stewart <kstewart@...uxfoundation.org>, linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org, Dongdong Liu <liudongdong3@...wei.com>, Gabriele Paoloni <gabriele.paoloni@...wei.com>, Keith Busch <keith.busch@...el.com>, Wei Zhang <wzhang@...com>, Sinan Kaya <okaya@...eaurora.org>, Timur Tabi <timur@...eaurora.org> Cc: Oza Pawandeep <poza@...eaurora.org> Subject: [PATCH 2/4] PCI/DPC/AER: Address Concurrency between AER and DPC This patch addresses the race condition between AER and DPC for recovery. Current DPC driver does not do recovery, e.g. calling end-point's driver's callbacks, which sanitize the device. DPC driver implements link_reset callback, and calls pci_do_recovery. Signed-off-by: Oza Pawandeep <poza@...eaurora.org> diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c index 2d976a6..e7ced58 100644 --- a/drivers/pci/pcie/pcie-dpc.c +++ b/drivers/pci/pcie/pcie-dpc.c @@ -15,6 +15,9 @@ #include <linux/pci.h> #include <linux/pcieport_if.h> #include "../pci.h" +#include "portdrv.h" + +static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev); struct rp_pio_header_log_regs { u32 dw0; @@ -67,6 +70,60 @@ struct dpc_dev { "Memory Request Completion Timeout", /* Bit Position 18 */ }; +static int find_dpc_dev_iter(struct device *device, void *data) +{ + struct pcie_port_service_driver *service_driver; + struct device **dev; + + dev = (struct device **) data; + + if (device->bus == &pcie_port_bus_type && device->driver) { + service_driver = to_service_driver(device->driver); + if (service_driver->service == PCIE_PORT_SERVICE_DPC) { + *dev = device; + return 1; + } + } + + return 0; +} + +struct device *pci_find_dpc_dev(struct pci_dev *pdev) +{ + struct device *dev = NULL; + + device_for_each_child(&pdev->dev, &dev, find_dpc_dev_iter); + + return dev; +} + +static int find_dpc_service_iter(struct device *device, void *data) +{ + struct pcie_port_service_driver *service_driver, **drv; + + drv = (struct pcie_port_service_driver **) data; + + if (device->bus == &pcie_port_bus_type && device->driver) { + service_driver = to_service_driver(device->driver); + if (service_driver->service == PCIE_PORT_SERVICE_DPC) { + *drv = service_driver; + return 1; + } + } + + return 0; +} + +struct pcie_port_service_driver *pci_find_dpc_service(struct pci_dev *dev) +{ + struct pcie_port_service_driver *drv = NULL; + + device_for_each_child(&dev->dev, &drv, find_dpc_service_iter); + + return drv; +} +EXPORT_SYMBOL(pci_find_dpc_service); + static int dpc_wait_rp_inactive(struct dpc_dev *dpc) { unsigned long timeout = jiffies + HZ; @@ -104,11 +161,23 @@ static void dpc_wait_link_inactive(struct dpc_dev *dpc) dev_warn(dev, "Link state not disabled for DPC event\n"); } -static void interrupt_event_handler(struct work_struct *work) +/** + * dpc_reset_link - reset link DPC routine + * @dev: pointer to Root Port's pci_dev data structure + * + * Invoked by Port Bus driver when performing link reset at Root Port. + */ +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; + struct pci_dev *dev, *temp; + struct dpc_dev *dpc; + struct pcie_device *pciedev; + struct device *devdpc; + + devdpc = pci_find_dpc_dev(pdev); + pciedev = to_pcie_device(devdpc); + dpc = get_service_data(pciedev); pci_lock_rescan_remove(); list_for_each_entry_safe_reverse(dev, temp, &parent->devices, @@ -125,7 +194,7 @@ static void interrupt_event_handler(struct work_struct *work) dpc_wait_link_inactive(dpc); if (dpc->rp && dpc_wait_rp_inactive(dpc)) - return; + return PCI_ERS_RESULT_DISCONNECT; if (dpc->rp && dpc->rp_pio_status) { pci_write_config_dword(pdev, dpc->cap_pos + PCI_EXP_DPC_RP_PIO_STATUS, @@ -135,6 +204,17 @@ static void interrupt_event_handler(struct work_struct *work) pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS, PCI_EXP_DPC_STATUS_TRIGGER | PCI_EXP_DPC_STATUS_INTERRUPT); + + return PCI_ERS_RESULT_RECOVERED; +} + +static void interrupt_event_handler(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. */ + pci_do_recovery(pdev, PCI_ERR_DPC_FATAL); } static void dpc_rp_pio_print_tlp_header(struct device *dev, @@ -339,6 +419,7 @@ static void dpc_remove(struct pcie_device *dev) .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/pcie-err.c b/drivers/pci/pcie/pcie-err.c index d59866c..8bac584 100644 --- a/drivers/pci/pcie/pcie-err.c +++ b/drivers/pci/pcie/pcie-err.c @@ -176,7 +176,7 @@ static pci_ers_result_t pci_default_reset_link(struct pci_dev *dev) return PCI_ERS_RESULT_RECOVERED; } -pci_ers_result_t pci_reset_link(struct pci_dev *dev) +pci_ers_result_t pci_reset_link(struct pci_dev *dev, int severity) { struct pci_dev *udev; pci_ers_result_t status; @@ -191,7 +191,10 @@ pci_ers_result_t pci_reset_link(struct pci_dev *dev) } /* Use the aer driver of the component firstly */ - driver = pci_find_aer_service(udev); + if (severity == PCI_ERR_DPC_FATAL) + driver = pci_find_dpc_service(udev); + else + driver = pci_find_aer_service(udev); if (driver && driver->reset_link) { status = driver->reset_link(udev); @@ -280,7 +283,8 @@ void pci_do_recovery(struct pci_dev *dev, int severity) mutex_lock(&pci_err_recovery_lock); - if (severity == PCI_ERR_AER_FATAL) + if ((severity == PCI_ERR_AER_FATAL) || + (severity == PCI_ERR_DPC_FATAL)) state = pci_channel_io_frozen; else state = pci_channel_io_normal; @@ -290,8 +294,9 @@ void pci_do_recovery(struct pci_dev *dev, int severity) "error_detected", pci_report_error_detected); - if (severity == PCI_ERR_AER_FATAL) { - result = pci_reset_link(dev); + if ((severity == PCI_ERR_AER_FATAL) || + (severity == PCI_ERR_DPC_FATAL)) { + result = pci_reset_link(dev, severity); if (result != PCI_ERS_RESULT_RECOVERED) goto failed; } diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h index 4f1992d..b013e24 100644 --- a/drivers/pci/pcie/portdrv.h +++ b/drivers/pci/pcie/portdrv.h @@ -80,4 +80,5 @@ static inline void pcie_port_platform_notify(struct pci_dev *port, int *mask){} #endif /* !CONFIG_ACPI */ struct pcie_port_service_driver *pci_find_aer_service(struct pci_dev *dev); +struct pcie_port_service_driver *pci_find_dpc_service(struct pci_dev *dev); #endif /* _PORTDRV_H_ */ diff --git a/include/linux/pci.h b/include/linux/pci.h index 083408e..123ee15 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -2005,6 +2005,7 @@ static inline resource_size_t pci_iov_resource_size(struct pci_dev *dev, int res #define PCI_ERR_AER_NONFATAL 0 #define PCI_ERR_AER_FATAL 1 #define PCI_ERR_AER_CORRECTABLE 2 +#define PCI_ERR_DPC_FATAL 4 pci_ers_result_t pci_broadcast_error_message(struct pci_dev *dev, enum pci_channel_state state, @@ -2014,7 +2015,7 @@ pci_ers_result_t pci_broadcast_error_message(struct pci_dev *dev, int pci_report_slot_reset(struct pci_dev *dev, void *data); int pci_report_resume(struct pci_dev *dev, void *data); int pci_report_error_detected(struct pci_dev *dev, void *data); -pci_ers_result_t pci_reset_link(struct pci_dev *dev); +pci_ers_result_t pci_reset_link(struct pci_dev *dev, int severity); pci_ers_result_t pci_merge_result(enum pci_ers_result orig, enum pci_ers_result new); void pci_do_recovery(struct pci_dev *dev, int severity); -- Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc., a Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
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