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path: root/drivers/pci/remove.c
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2024-11-30PCI/pwrctrl: Unregister platform device only if one actually existsBrian Norris1-2/+7
If a PCI device has an associated device_node with power supplies, pci_bus_add_device() creates platform devices for use by pwrctrl. When the PCI device is removed, pci_stop_dev() uses of_find_device_by_node() to locate the related platform device, then unregisters it. But when we remove a PCI device with no associated device node, dev_of_node(dev) is NULL, and of_find_device_by_node(NULL) returns the first device with "dev->of_node == NULL". The result is that we (a) mistakenly unregister a completely unrelated platform device, leading to issues like the first trace below, and (b) dereference the NULL pointer from dev_of_node() when clearing OF_POPULATED, as in the second trace. Unregister a platform device only if there is one associated with this PCI device. This resolves issues seen when doing: # echo 1 > /sys/bus/pci/devices/.../remove Sample issue from unregistering the wrong platform device: WARNING: CPU: 0 PID: 5095 at drivers/regulator/core.c:5885 regulator_unregister+0x140/0x160 Call trace: regulator_unregister+0x140/0x160 devm_rdev_release+0x1c/0x30 release_nodes+0x68/0x100 devres_release_all+0x98/0xf8 device_unbind_cleanup+0x20/0x70 device_release_driver_internal+0x1f4/0x240 device_release_driver+0x20/0x40 bus_remove_device+0xd8/0x170 device_del+0x154/0x380 device_unregister+0x28/0x88 of_device_unregister+0x1c/0x30 pci_stop_bus_device+0x154/0x1b0 pci_stop_and_remove_bus_device_locked+0x28/0x48 remove_store+0xa0/0xb8 dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 Later NULL pointer dereference for of_node_clear_flag(NULL, OF_POPULATED): Unable to handle kernel NULL pointer dereference at virtual address 00000000000000c0 Call trace: pci_stop_bus_device+0x190/0x1b0 pci_stop_and_remove_bus_device_locked+0x28/0x48 remove_store+0xa0/0xb8 dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 Link: https://lore.kernel.org/r/20241126210443.4052876-1-briannorris@chromium.org Fixes: 681725afb6b9 ("PCI/pwrctl: Remove pwrctl device without iterating over all children of pwrctl parent") Reported-by: Saurabh Sengar <ssengar@linux.microsoft.com> Closes: https://lore.kernel.org/r/1732890621-19656-1-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Brian Norris <briannorris@chromium.org> [bhelgaas: commit log] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2024-11-25Merge branch 'pci/pwrctl'Bjorn Helgaas1-9/+8
- Use of_platform_device_create() instead of of_platform_populate() to create pwrctl platform devices so we can control it based on the child nodes (Manivannan Sadhasivam) - Create pwrctrl platform devices only if there's a relevant power supply property (Manivannan Sadhasivam) - Add device link from the pwrctl supplier to the PCI dev to ensure pwrctl drivers are probed before the PCI dev driver; this avoids a race where pwrctl could change device power state while the PCI driver was active (Manivannan Sadhasivam) - Find pwrctl device for removal with of_find_device_by_node() instead of searching all children of the parent (Manivannan Sadhasivam) - Rename 'pwrctl' to 'pwrctrl' to use the same 'ctrl' suffix as 'bwctrl' and other PCI files to reduce confusion (Bjorn Helgaas) * pci/pwrctl: PCI/pwrctrl: Rename pwrctrl functions and structures PCI/pwrctrl: Rename pwrctl files to pwrctrl PCI/pwrctl: Remove pwrctl device without iterating over all children of pwrctl parent PCI/pwrctl: Ensure that pwrctl drivers are probed before PCI client drivers PCI/pwrctl: Create pwrctl device only if at least one power supply is present PCI/pwrctl: Use of_platform_device_create() to create pwrctl devices # Conflicts: # drivers/pci/bus.c # drivers/pci/remove.c
2024-11-21PCI/pwrctrl: Rename pwrctrl functions and structuresBjorn Helgaas1-2/+2
Rename pwrctrl functions and structures from "pwrctl" to "pwrctrl" to match the similar file renames. Link: https://lore.kernel.org/r/20241115214428.2061153-3-helgaas@kernel.org Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org> Acked-by: Krzysztof Wilczyński <kw@linux.com>
2024-11-21PCI/pwrctl: Remove pwrctl device without iterating over all children of ↵Manivannan Sadhasivam1-9/+8
pwrctl parent There is no need to iterate over all children of the pwrctl device parent to remove the pwrctl device. Since the pwrctl device associated with the PCI device can be found using of_find_device_by_node() API, use it directly instead. Any pwrctl devices lying around without getting associated with the PCI devices will be removed once their parent device gets removed. Link: https://lore.kernel.org/r/20241025-pci-pwrctl-rework-v2-5-568756156cbe@linaro.org Tested-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Tested-by: Krishna chaitanya chundru <quic_krichai@quicinc.com> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> [bhelgaas: commit log] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org> Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2024-11-11PCI: Make pci_destroy_dev() concurrent safeKeith Busch1-1/+1
Use an atomic flag instead of the racy check against the device's kobj parent. We shouldn't be poking into device implementation details at this level anyway. Link: https://lore.kernel.org/r/20241022224851.340648-3-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-11-11PCI: Make pci_stop_dev() concurrent safeKeith Busch1-10/+9
Use the atomic ADDED flag to ensure concurrent callers can't attempt to stop the device multiple times. Callers should currently all be holding the pci_rescan_remove_lock, so there shouldn't be an existing race. But that global lock can cause lock dependency issues, so this is preparing to reduce reliance on that lock by using the existing existing atomic bit ops. Link: https://lore.kernel.org/r/20241022224851.340648-2-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> [bhelgaas: squash https://lore.kernel.org/r/20241111180659.3321671-1-kbusch@meta.com] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-09-23Merge tag 'pci-v6.12-changes' of ↵Linus Torvalds1-1/+3
git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci Pull pci updates from Bjorn Helgaas: "Enumeration: - Wait for device readiness after reset by polling Vendor ID and looking for Configuration RRS instead of polling the Command register and looking for non-error completions, to avoid hardware retries done for RRS on non-Vendor ID reads (Bjorn Helgaas) - Rename CRS Completion Status to RRS ('Request Retry Status') to match PCIe r6.0 spec usage (Bjorn Helgaas) - Clear LBMS bit after a manual link retrain so we don't try to retrain a link when there's no downstream device anymore (Maciej W. Rozycki) - Revert to the original link speed after retraining fails instead of leaving it restricted to 2.5GT/s, so a future device has a chance to use higher speeds (Maciej W. Rozycki) - Wait for each level of downstream bus, not just the first, to become accessible before restoring devices on that bus (Ilpo Järvinen) - Add ARCH_PCI_DEV_GROUPS so s390 can add its own attribute_groups without having to stomp on the core's pdev->dev.groups (Lukas Wunner) Driver binding: - Export pcim_request_region(), a managed counterpart of pci_request_region(), for use by drivers (Philipp Stanner) - Export pcim_iomap_region() and deprecate pcim_iomap_regions() (Philipp Stanner) - Request the PCI BAR used by xboxvideo (Philipp Stanner) - Request and map drm/ast BARs with pcim_iomap_region() (Philipp Stanner) MSI: - Add MSI_FLAG_NO_AFFINITY flag for devices that mux MSIs onto a single IRQ line and cannot set the affinity of each MSI to a specific CPU core (Marek Vasut) - Use MSI_FLAG_NO_AFFINITY and remove unnecessary .irq_set_affinity() implementations in aardvark, altera, brcmstb, dwc, mediatek-gen3, mediatek, mobiveil, plda, rcar, tegra, vmd, xilinx-nwl, xilinx-xdma, and xilinx drivers to avoid 'IRQ: set affinity failed' warnings (Marek Vasut) Power management: - Add pwrctl support for ATH11K inside the WCN6855 package (Konrad Dybcio) PCI device hotplug: - Remove unnecessary hpc_ops struct from shpchp (ngn) - Check for PCI_POSSIBLE_ERROR(), not 0xffffffff, in cpqphp (weiyufeng) Virtualization: - Mark Creative Labs EMU20k2 INTx masking as broken (Alex Williamson) - Add an ACS quirk for Qualcomm SA8775P, which doesn't advertise ACS but does provide ACS-like features (Subramanian Ananthanarayanan) IOMMU: - Add function 0 DMA alias quirk for Glenfly Arise audio function, which uses the function 0 Requester ID (WangYuli) NPEM: - Add Native PCIe Enclosure Management (NPEM) support for sysfs control of NVMe RAID storage indicators (ok/fail/locate/ rebuild/etc) (Mariusz Tkaczyk) - Add support for the ACPI _DSM PCIe SSD status LED management, which is functionally similar to NPEM but mediated by platform firmware (Mariusz Tkaczyk) Device trees: - Drop minItems and maxItems from ranges in PCI generic host binding since host bridges may have several MMIO and I/O port apertures (Frank Li) - Add kirin, rcar-gen2, uniphier DT binding top-level constraints for clocks (Krzysztof Kozlowski) Altera PCIe controller driver: - Convert altera DT bindings from text to YAML (Matthew Gerlach) - Replace TLP_REQ_ID() with macro PCI_DEVID(), which does the same thing and is what other drivers use (Jinjie Ruan) Broadcom STB PCIe controller driver: - Add DT binding maxItems for reset controllers (Jim Quinlan) - Use the 'bridge' reset method if described in the DT (Jim Quinlan) - Use the 'swinit' reset method if described in the DT (Jim Quinlan) - Add 'has_phy' so the existence of a 'rescal' reset controller doesn't imply software control of it (Jim Quinlan) - Add support for many inbound DMA windows (Jim Quinlan) - Rename SoC 'type' to 'soc_base' express the fact that SoCs come in families of multiple similar devices (Jim Quinlan) - Add Broadcom 7712 DT description and driver support (Jim Quinlan) - Sort enums, pcie_offsets[], pcie_cfg_data, .compatible strings for maintainability (Bjorn Helgaas) Freescale i.MX6 PCIe controller driver: - Add imx6q-pcie 'dbi2' and 'atu' reg-names for i.MX8M Endpoints (Richard Zhu) - Fix a code restructuring error that caused i.MX8MM and i.MX8MP Endpoints to fail to establish link (Richard Zhu) - Fix i.MX8MP Endpoint occasional failure to trigger MSI by enforcing outbound alignment requirement (Richard Zhu) - Call phy_power_off() in the .probe() error path (Frank Li) - Rename internal names from imx6_* to imx_* since i.MX7/8/9 are also supported (Frank Li) - Manage Refclk by using SoC-specific callbacks instead of switch statements (Frank Li) - Manage core reset by using SoC-specific callbacks instead of switch statements (Frank Li) - Expand comments for erratum ERR010728 workaround (Frank Li) - Use generic PHY APIs to configure mode, speed, and submode, which is harmless for devices that implement their own internal PHY management and don't set the generic imx_pcie->phy (Frank Li) - Add i.MX8Q (i.MX8QM, i.MX8QXP, and i.MX8DXL) DT binding and driver Root Complex support (Richard Zhu) Freescale Layerscape PCIe controller driver: - Replace layerscape-pcie DT binding compatible fsl,lx2160a-pcie with fsl,lx2160ar2-pcie (Frank Li) - Add layerscape-pcie DT binding deprecated 'num-viewport' property to address a DT checker warning (Frank Li) - Change layerscape-pcie DT binding 'fsl,pcie-scfg' to phandle-array (Frank Li) Loongson PCIe controller driver: - Increase max PCI hosts to 8 for Loongson-3C6000 and newer chipsets (Huacai Chen) Marvell Aardvark PCIe controller driver: - Fix issue with emulating Configuration RRS for two-byte reads of Vendor ID; previously it only worked for four-byte reads (Bjorn Helgaas) MediaTek PCIe Gen3 controller driver: - Add per-SoC struct mtk_gen3_pcie_pdata to support multiple SoC types (Lorenzo Bianconi) - Use reset_bulk APIs to manage PHY reset lines (Lorenzo Bianconi) - Add DT and driver support for Airoha EN7581 PCIe controller (Lorenzo Bianconi) Qualcomm PCIe controller driver: - Update qcom,pcie-sc7280 DT binding with eight interrupts (Rayyan Ansari) - Add back DT 'vddpe-3v3-supply', which was incorrectly removed earlier (Johan Hovold) - Drop endpoint redundant masking of global IRQ events (Manivannan Sadhasivam) - Clarify unknown global IRQ message and only log it once to avoid a flood (Manivannan Sadhasivam) - Add 'linux,pci-domain' property to endpoint DT binding (Manivannan Sadhasivam) - Assign PCI domain number for endpoint controllers (Manivannan Sadhasivam) - Add 'qcom_pcie_ep' and the PCI domain number to IRQ names for endpoint controller (Manivannan Sadhasivam) - Add global SPI interrupt for PCIe link events to DT binding (Manivannan Sadhasivam) - Add global RC interrupt handler to handle 'Link up' events and automatically enumerate hot-added devices (Manivannan Sadhasivam) - Avoid mirroring of DBI and iATU register space so it doesn't overlap BAR MMIO space (Prudhvi Yarlagadda) - Enable controller resources like PHY only after PERST# is deasserted to partially avoid the problem that the endpoint SoC crashes when accessing things when Refclk is absent (Manivannan Sadhasivam) - Add 16.0 GT/s equalization and RX lane margining settings (Shashank Babu Chinta Venkata) - Pass domain number to pci_bus_release_domain_nr() explicitly to avoid a NULL pointer dereference (Manivannan Sadhasivam) Renesas R-Car PCIe controller driver: - Make the read-only const array 'check_addr' static (Colin Ian King) - Add R-Car V4M (R8A779H0) PCIe host and endpoint to DT binding (Yoshihiro Shimoda) TI DRA7xx PCIe controller driver: - Request IRQF_ONESHOT for 'dra7xx-pcie-main' IRQ since the primary handler is NULL (Siddharth Vadapalli) - Handle IRQ request errors during root port and endpoint probe (Siddharth Vadapalli) TI J721E PCIe driver: - Add DT 'ti,syscon-acspcie-proxy-ctrl' and driver support to enable the ACSPCIE module to drive Refclk for the Endpoint (Siddharth Vadapalli) - Extract the cadence link setup from cdns_pcie_host_setup() so link setup can be done separately during resume (Thomas Richard) - Add T_PERST_CLK_US definition for the mandatory delay between Refclk becoming stable and PERST# being deasserted (Thomas Richard) - Add j721e suspend and resume support (Théo Lebrun) TI Keystone PCIe controller driver: - Fix NULL pointer checking when applying MRRS limitation quirk for AM65x SR 1.0 Errata #i2037 (Dan Carpenter) Xilinx NWL PCIe controller driver: - Fix off-by-one error in INTx IRQ handler that caused INTx interrupts to be lost or delivered as the wrong interrupt (Sean Anderson) - Rate-limit misc interrupt messages (Sean Anderson) - Turn off the clock on probe failure and device removal (Sean Anderson) - Add DT binding and driver support for enabling/disabling PHYs (Sean Anderson) - Add PCIe phy bindings for the ZCU102 (Sean Anderson) Xilinx XDMA PCIe controller driver: - Add support for Xilinx QDMA Soft IP PCIe Root Port Bridge to DT binding and xilinx-dma-pl driver (Thippeswamy Havalige) Miscellaneous: - Fix buffer overflow in kirin_pcie_parse_port() (Alexandra Diupina) - Fix minor kerneldoc issues and typos (Bjorn Helgaas) - Use PCI_DEVID() macro in aer_inject() instead of open-coding it (Jinjie Ruan) - Check pcie_find_root_port() return in x86 fixups to avoid NULL pointer dereferences (Samasth Norway Ananda) - Make pci_bus_type constant (Kunwu Chan) - Remove unused declarations of __pci_pme_wakeup() and pci_vpd_release() (Yue Haibing) - Remove any leftover .*.cmd files with make clean (zhang jiao) - Remove unused BILLION macro (zhang jiao)" * tag 'pci-v6.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (132 commits) PCI: Fix typos dt-bindings: PCI: qcom: Allow 'vddpe-3v3-supply' again tools: PCI: Remove unused BILLION macro tools: PCI: Remove .*.cmd files with make clean PCI: Pass domain number to pci_bus_release_domain_nr() explicitly PCI: dra7xx: Fix error handling when IRQ request fails in probe PCI: dra7xx: Fix threaded IRQ request for "dra7xx-pcie-main" IRQ PCI: qcom: Add RX lane margining settings for 16.0 GT/s PCI: qcom: Add equalization settings for 16.0 GT/s PCI: dwc: Always cache the maximum link speed value in dw_pcie::max_link_speed PCI: dwc: Rename 'dw_pcie::link_gen' to 'dw_pcie::max_link_speed' PCI: qcom-ep: Enable controller resources like PHY only after refclk is available PCI: Mark Creative Labs EMU20k2 INTx masking as broken dt-bindings: PCI: imx6q-pcie: Add reg-name "dbi2" and "atu" for i.MX8M PCIe Endpoint dt-bindings: PCI: altera: msi: Convert to YAML PCI: imx6: Add i.MX8Q PCIe Root Complex (RC) support PCI: Rename CRS Completion Status to RRS PCI: aardvark: Correct Configuration RRS checking PCI: Wait for device readiness with Configuration RRS PCI: brcmstb: Sort enums, pcie_offsets[], pcie_cfg_data, .compatible strings ...
2024-09-19Merge branch 'pci/controller/qcom'Bjorn Helgaas1-1/+1
- Drop endpoint redundant masking of global IRQ events (Manivannan Sadhasivam) - Clarify unknown global IRQ message and only log it once to avoid a flood (Manivannan Sadhasivam) - Add Manivannan Sadhasivam as maintainer of qcom endpoint driver (Manivannan Sadhasivam) - Add 'linux,pci-domain' property to endpoint DT binding (Manivannan Sadhasivam) - Assign PCI domain number for endpoint controllers (Manivannan Sadhasivam) - Add 'qcom_pcie_ep' and the PCI domain number to IRQ names for endpoint controller (Manivannan Sadhasivam) - Add global SPI interrupt for PCIe link events to DT binding (Manivannan Sadhasivam) - Add global RC interrupt handler to handle 'Link up' events and automatically enumerate hot-added devices (Manivannan Sadhasivam) - Avoid mirroring of DBI and iATU register space so it doesn't overlap BAR MMIO space (Prudhvi Yarlagadda) - Enable controller resources like PHY only after PERST# is deasserted to partially avoid the problem that the endpoint SoC crashes when accessing things when Refclk is absent (Manivannan Sadhasivam) - Rename dw_pcie.link_gen to max_link_speed to avoid ambiguity (Manivannan Sadhasivam) - Cache maximum link speed value in dw_pcie.max_link_speed for use by vendor drivers (Manivannan Sadhasivam) - Add 16.0 GT/s equalization and RX lane margining settings (Shashank Babu Chinta Venkata) - Pass domain number to pci_bus_release_domain_nr() explicitly to avoid a NULL pointer dereference (Manivannan Sadhasivam) * pci/controller/qcom: PCI: Pass domain number to pci_bus_release_domain_nr() explicitly PCI: qcom: Add RX lane margining settings for 16.0 GT/s PCI: qcom: Add equalization settings for 16.0 GT/s PCI: dwc: Always cache the maximum link speed value in dw_pcie::max_link_speed PCI: dwc: Rename 'dw_pcie::link_gen' to 'dw_pcie::max_link_speed' PCI: qcom-ep: Enable controller resources like PHY only after refclk is available PCI: qcom: Disable mirroring of DBI and iATU register space in BAR region PCI: qcom: Enumerate endpoints based on Link up event in 'global_irq' interrupt dt-bindings: PCI: qcom,pcie-sm8450: Add 'global' interrupt PCI: qcom-ep: Modify 'global_irq' and 'perst_irq' IRQ device names PCI: endpoint: Assign PCI domain number for endpoint controllers dt-bindings: PCI: pci-ep: Document 'linux,pci-domain' property dt-bindings: PCI: pci-ep: Update Maintainers PCI: qcom-ep: Reword the error message for receiving unknown global IRQ event PCI: qcom-ep: Drop the redundant masking of global IRQ events
2024-09-14PCI: Pass domain number to pci_bus_release_domain_nr() explicitlyManivannan Sadhasivam1-1/+1
The pci_bus_release_domain_nr() API is supposed to free the domain number allocated by pci_bus_find_domain_nr(). Most of the callers of pci_bus_find_domain_nr(), store the domain number in pci_bus::domain_nr. As such, the pci_bus_release_domain_nr() implicitly frees the domain number by dereferencing 'struct pci_bus'. However, one of the callers of this API, the PCI endpoint subsystem, doesn't have 'struct pci_bus', so it only passes NULL. Due to this, the API will end up dereferencing the NULL pointer. To fix this issue, pass the domain number to this API explicitly. Since 'struct pci_bus' is not used for anything else other than extracting the domain number, it makes sense to pass the domain number directly. Fixes: 0328947c5032 ("PCI: endpoint: Assign PCI domain number for endpoint controllers") Closes: https://lore.kernel.org/linux-pci/c0c40ddb-bf64-4b22-9dd1-8dbb18aa2813@stanley.mountain Link: https://lore.kernel.org/linux-pci/20240912053025.25314-1-manivannan.sadhasivam@linaro.org Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> [kwilczynski: commit log] Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
2024-09-05PCI/NPEM: Add Native PCIe Enclosure Management supportMariusz Tkaczyk1-0/+2
Native PCIe Enclosure Management (NPEM, PCIe r6.1 sec 6.28) allows managing LEDs in storage enclosures. NPEM is indication oriented and it does not give direct access to LEDs. Although each indication *could* represent an individual LED, multiple indications could also be represented as a single, multi-color LED or a single LED blinking in a specific interval. The specification leaves that open. Each enabled indication (capability register bit on) is represented as a ledclass_dev which can be controlled through sysfs. For every ledclass device only 2 brightness states are allowed: LED_ON (1) or LED_OFF (0). This corresponds to the NPEM control register (Indication bit on/off). Ledclass devices appear in sysfs as child devices (subdirectory) of PCI device which has an NPEM Extended Capability and indication is enabled in NPEM capability register. For example, these are LEDs created for pcieport "10000:02:05.0" on my setup: leds/ ├── 10000:02:05.0:enclosure:fail ├── 10000:02:05.0:enclosure:locate ├── 10000:02:05.0:enclosure:ok └── 10000:02:05.0:enclosure:rebuild They can be also found in "/sys/class/leds" directory. The parent PCIe device domain/bus/device/function address is used to guarantee uniqueness across leds subsystem. To enable/disable a "fail" indication, the "brightness" file can be edited: echo 1 > ./leds/10000:02:05.0:enclosure:fail/brightness echo 0 > ./leds/10000:02:05.0:enclosure:fail/brightness PCIe r6.1, sec 7.9.19.2 defines the possible indications. Multiple indications for same parent PCIe device can conflict and hardware may update them when processing new request. To avoid issues, driver refresh all indications by reading back control register. This driver expects to be the exclusive NPEM extended capability manager. It waits up to 1 second after imposing new request, it doesn't verify if controller is busy before write, and it assumes the mutex lock gives protection from concurrent updates. If _DSM LED management is available, we assume the platform may be using NPEM for its own purposes (see PCI Firmware Spec r3.3 sec 4.7), so the driver does not use NPEM. A future patch will add _DSM support; an info message notes whether NPEM or _DSM is being used. NPEM is a PCIe extended capability so it should be registered in pcie_init_capabilities() but it is not possible due to LED dependency. The parent pci_device must be added earlier for led_classdev_register() to be successful. NPEM does not require configuration on kernel side, so it is safe to register LED devices later. Link: https://lore.kernel.org/r/20240904104848.23480-3-mariusz.tkaczyk@linux.intel.com Suggested-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Tested-by: Stuart Hayes <stuart.w.hayes@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
2024-09-04PCI: Don't rely on of_platform_depopulate() for reused OF-nodesBartosz Golaszewski1-1/+17
of_platform_depopulate() doesn't play nicely with reused OF nodes - it ignores the ones that are not marked explicitly as populated and it may happen that the PCI device goes away before the platform device in which case the PCI core clears the OF_POPULATED bit. Unconditionally unregister the platform devices for child nodes when stopping the PCI device. Link: https://lore.kernel.org/r/20240823093323.33450-2-brgl@bgdev.pl Fixes: 8fb18619d910 ("PCI/pwrctl: Create platform devices for child OF nodes of the port node") Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
2024-06-12PCI/pwrctl: Create platform devices for child OF nodes of the port nodeBartosz Golaszewski1-1/+2
In preparation for introducing PCI device power control - a set of library functions that will allow powering-up of PCI devices before they're detected on the PCI bus - we need to populate the devices defined on the device-tree. We are reusing the platform bus as it provides us with all the infrastructure we need to match the pwrctl drivers against the compatibles from OF nodes. These platform devices will be probed by the driver core and bound to the PCI pwrctl drivers we'll introduce later. Tested-by: Amit Pundir <amit.pundir@linaro.org> Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T Acked-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://lore.kernel.org/r/20240612082019.19161-4-brgl@bgdev.pl Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2023-08-22PCI: Create device tree node for bridgeLizhi Hou1-0/+1
The PCI endpoint device such as Xilinx Alveo PCI card maps the register spaces from multiple hardware peripherals to its PCI BAR. Normally, the PCI core discovers devices and BARs using the PCI enumeration process. There is no infrastructure to discover the hardware peripherals that are present in a PCI device, and which can be accessed through the PCI BARs. Apparently, the device tree framework requires a device tree node for the PCI device. Thus, it can generate the device tree nodes for hardware peripherals underneath. Because PCI is self discoverable bus, there might not be a device tree node created for PCI devices. Furthermore, if the PCI device is hot pluggable, when it is plugged in, the device tree nodes for its parent bridges are required. Add support to generate device tree node for PCI bridges. Add an of_pci_make_dev_node() interface that can be used to create device tree node for PCI devices. Add a PCI_DYNAMIC_OF_NODES config option. When the option is turned on, the kernel will generate device tree nodes for PCI bridges unconditionally. Initially, add the basic properties for the dynamically generated device tree nodes which include #address-cells, #size-cells, device_type, compatible, ranges, reg. Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com> Link: https://lore.kernel.org/r/1692120000-46900-3-git-send-email-lizhi.hou@amd.com Signed-off-by: Rob Herring <robh@kernel.org>
2023-04-30Merge tag 'cxl-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxlLinus Torvalds1-0/+1
Pull compute express link updates from Dan Williams: "DOE support is promoted from drivers/cxl/ to drivers/pci/ with Bjorn's blessing, and the CXL core continues to mature its media management capabilities with support for listing and injecting media errors. Some late fixes that missed v6.3-final are also included: - Refactor the DOE infrastructure (Data Object Exchange PCI-config-cycle mailbox) to be a facility of the PCI core rather than the CXL core. This is foundational for upcoming support for PCI device-attestation and PCIe / CXL link encryption. - Add support for retrieving and injecting poison for CXL memory expanders. This enabling uses trace-events to convey CXL media error records to user tooling. It includes translation of device-local addresses (DPA) to system physical addresses (SPA) and their corresponding CXL region. - Fixes for decoder enumeration that missed v6.3-final - Miscellaneous fixups" * tag 'cxl-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (38 commits) cxl/test: Add mock test for set_timestamp cxl/mbox: Update CMD_RC_TABLE tools/testing/cxl: Require CONFIG_DEBUG_FS tools/testing/cxl: Add a sysfs attr to test poison inject limits tools/testing/cxl: Use injected poison for get poison list tools/testing/cxl: Mock the Clear Poison mailbox command tools/testing/cxl: Mock the Inject Poison mailbox command cxl/mem: Add debugfs attributes for poison inject and clear cxl/memdev: Trace inject and clear poison as cxl_poison events cxl/memdev: Warn of poison inject or clear to a mapped region cxl/memdev: Add support for the Clear Poison mailbox command cxl/memdev: Add support for the Inject Poison mailbox command tools/testing/cxl: Mock support for Get Poison List cxl/trace: Add an HPA to cxl_poison trace events cxl/region: Provide region info to the cxl_poison trace event cxl/memdev: Add trigger_poison_list sysfs attribute cxl/trace: Add TRACE support for CXL media-error records cxl/mbox: Add GET_POISON_LIST mailbox command cxl/mbox: Initialize the poison state cxl/mbox: Restrict poison cmds to debugfs cxl_raw_allow_all ...
2023-04-27Merge tag 'pci-v6.4-changes' of ↵Linus Torvalds1-3/+2
git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci Pull pci updates from Bjorn Helgaas: "Resource management: - Add pci_dev_for_each_resource() and pci_bus_for_each_resource() iterators PCIe native device hotplug: - Fix AB-BA deadlock between reset_lock and device_lock Power management: - Wait longer for devices to become ready after resume (as we do for reset) to accommodate Intel Titan Ridge xHCI devices - Extend D3hot delay for NVIDIA HDA controllers to avoid unrecoverable devices after a bus reset Error handling: - Clear PCIe Device Status after EDR since generic error recovery now only clears it when AER is native ASPM: - Work around Chromebook firmware defect that clobbers Capability list (including ASPM L1 PM Substates Cap) when returning from D3cold to D0 Freescale i.MX6 PCIe controller driver: - Install imprecise external abort handler only when DT indicates PCIe support Freescale Layerscape PCIe controller driver: - Add ls1028a endpoint mode support Qualcomm PCIe controller driver: - Add SM8550 DT binding and driver support - Add SDX55 DT binding and driver support - Use bulk APIs for clocks of IP 1.0.0, 2.3.2, 2.3.3 - Use bulk APIs for reset of IP 2.1.0, 2.3.3, 2.4.0 - Add DT "mhi" register region for supported SoCs - Expose link transition counts via debugfs to help debug low power issues - Support system suspend and resume; reduce interconnect bandwidth and turn off clock and PHY if there are no active devices - Enable async probe by default to reduce boot time Miscellaneous: - Sort controller Kconfig entries by vendor" * tag 'pci-v6.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (56 commits) PCI: xilinx: Drop obsolete dependency on COMPILE_TEST PCI: mobiveil: Sort Kconfig entries by vendor PCI: dwc: Sort Kconfig entries by vendor PCI: Sort controller Kconfig entries by vendor PCI: Use consistent controller Kconfig menu entry language PCI: xilinx-nwl: Add 'Xilinx' to Kconfig prompt PCI: hv: Add 'Microsoft' to Kconfig prompt PCI: meson: Add 'Amlogic' to Kconfig prompt PCI: Use of_property_present() for testing DT property presence PCI/PM: Extend D3hot delay for NVIDIA HDA controllers dt-bindings: PCI: qcom: Document msi-map and msi-map-mask properties PCI: qcom: Add SM8550 PCIe support dt-bindings: PCI: qcom: Add SM8550 compatible PCI: qcom: Add support for SDX55 SoC dt-bindings: PCI: qcom-ep: Fix the unit address used in example dt-bindings: PCI: qcom: Add SDX55 SoC dt-bindings: PCI: qcom: Update maintainers entry PCI: qcom: Enable async probe by default PCI: qcom: Add support for system suspend and resume PCI/PM: Drop pci_bridge_wait_for_secondary_bus() timeout parameter ...
2023-04-18PCI/DOE: Create mailboxes on device enumerationLukas Wunner1-0/+1
Currently a DOE instance cannot be shared by multiple drivers because each driver creates its own pci_doe_mb struct for a given DOE instance. For the same reason a DOE instance cannot be shared between the PCI core and a driver. Moreover, finding out which protocols a DOE instance supports requires creating a pci_doe_mb for it. If a device has multiple DOE instances, a driver looking for a specific protocol may need to create a pci_doe_mb for each of the device's DOE instances and then destroy those which do not support the desired protocol. That's obviously an inefficient way to do things. Overcome these issues by creating mailboxes in the PCI core on device enumeration. Provide a pci_find_doe_mailbox() API call to allow drivers to get a pci_doe_mb for a given (pci_dev, vendor, protocol) triple. This API is modeled after pci_find_capability() and can later be amended with a pci_find_next_doe_mailbox() call to iterate over all mailboxes of a given pci_dev which support a specific protocol. On removal, destroy the mailboxes in pci_destroy_dev(), after the driver is unbound. This allows drivers to use DOE in their ->remove() hook. On surprise removal, cancel ongoing DOE exchanges and prevent new ones from being scheduled. Thereby ensure that a hot-removed device doesn't needlessly wait for a running exchange to time out. Tested-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Reviewed-by: Ming Li <ming4.li@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://lore.kernel.org/r/40a6f973f72ef283d79dd55e7e6fddc7481199af.1678543498.git.lukas@wunner.de Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-04-07PCI: Fix use-after-free in pci_bus_release_domain_nr()Rob Herring1-2/+3
Commit c14f7ccc9f5d ("PCI: Assign PCI domain IDs by ida_alloc()") introduced a use-after-free bug in the bus removal cleanup. The issue was found with kfence: [ 19.293351] BUG: KFENCE: use-after-free read in pci_bus_release_domain_nr+0x10/0x70 [ 19.302817] Use-after-free read at 0x000000007f3b80eb (in kfence-#115): [ 19.309677] pci_bus_release_domain_nr+0x10/0x70 [ 19.309691] dw_pcie_host_deinit+0x28/0x78 [ 19.309702] tegra_pcie_deinit_controller+0x1c/0x38 [pcie_tegra194] [ 19.309734] tegra_pcie_dw_probe+0x648/0xb28 [pcie_tegra194] [ 19.309752] platform_probe+0x90/0xd8 ... [ 19.311457] kfence-#115: 0x00000000063a155a-0x00000000ba698da8, size=1072, cache=kmalloc-2k [ 19.311469] allocated by task 96 on cpu 10 at 19.279323s: [ 19.311562] __kmem_cache_alloc_node+0x260/0x278 [ 19.311571] kmalloc_trace+0x24/0x30 [ 19.311580] pci_alloc_bus+0x24/0xa0 [ 19.311590] pci_register_host_bridge+0x48/0x4b8 [ 19.311601] pci_scan_root_bus_bridge+0xc0/0xe8 [ 19.311613] pci_host_probe+0x18/0xc0 [ 19.311623] dw_pcie_host_init+0x2c0/0x568 [ 19.311630] tegra_pcie_dw_probe+0x610/0xb28 [pcie_tegra194] [ 19.311647] platform_probe+0x90/0xd8 ... [ 19.311782] freed by task 96 on cpu 10 at 19.285833s: [ 19.311799] release_pcibus_dev+0x30/0x40 [ 19.311808] device_release+0x30/0x90 [ 19.311814] kobject_put+0xa8/0x120 [ 19.311832] device_unregister+0x20/0x30 [ 19.311839] pci_remove_bus+0x78/0x88 [ 19.311850] pci_remove_root_bus+0x5c/0x98 [ 19.311860] dw_pcie_host_deinit+0x28/0x78 [ 19.311866] tegra_pcie_deinit_controller+0x1c/0x38 [pcie_tegra194] [ 19.311883] tegra_pcie_dw_probe+0x648/0xb28 [pcie_tegra194] [ 19.311900] platform_probe+0x90/0xd8 ... [ 19.313579] CPU: 10 PID: 96 Comm: kworker/u24:2 Not tainted 6.2.0 #4 [ 19.320171] Hardware name: /, BIOS 1.0-d7fb19b 08/10/2022 [ 19.325852] Workqueue: events_unbound deferred_probe_work_func The stack trace is a bit misleading as dw_pcie_host_deinit() doesn't directly call pci_bus_release_domain_nr(). The issue turns out to be in pci_remove_root_bus() which first calls pci_remove_bus() which frees the struct pci_bus when its struct device is released. Then pci_bus_release_domain_nr() is called and accesses the freed struct pci_bus. Reordering these fixes the issue. Fixes: c14f7ccc9f5d ("PCI: Assign PCI domain IDs by ida_alloc()") Link: https://lore.kernel.org/r/20230329123835.2724518-1-robh@kernel.org Link: https://lore.kernel.org/r/b529cb69-0602-9eed-fc02-2f068707a006@nvidia.com Reported-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Rob Herring <robh@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Cc: stable@vger.kernel.org # v6.2+ Cc: Pali Rohár <pali@kernel.org>
2023-04-04PCI: Introduce pci_dev_for_each_resource()Mika Westerberg1-3/+2
Instead of open-coding it everywhere introduce a tiny helper that can be used to iterate over each resource of a PCI device, and convert the most obvious users into it. While at it drop doubled empty line before pdev_sort_resources(). No functional changes intended. Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230330162434.35055-4-andriy.shevchenko@linux.intel.com Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Krzysztof Wilczyński <kw@linux.com>
2022-11-08PCI: Assign PCI domain IDs by ida_alloc()Pali Rohár1-0/+6
Replace assignment of PCI domain IDs from atomic_inc_return() to ida_alloc(). Use two IDAs, one for static domain allocations (those which are defined in device tree) and second for dynamic allocations (all other). During removal of root bus / host bridge, also release the domain ID. The released ID can be reused again, for example when dynamically loading and unloading native PCI host bridge drivers. This change also allows to mix static device tree assignment and dynamic by kernel as all static allocations are reserved in dynamic pool. [bhelgaas: set "err" if "bus->domain_nr < 0"] Link: https://lore.kernel.org/r/20220714184130.5436-1-pali@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2021-08-18PCI: Remove reset_fn field from pci_devAmey Narkhede1-1/+0
"reset_fn" indicates whether the device supports any reset mechanism. Remove the use of reset_fn in favor of the reset_methods array that tracks supported reset mechanisms of a device and their ordering. The octeon driver incorrectly used reset_fn to detect whether the device supports FLR or not. Use pcie_reset_flr() to probe whether it supports FLR. Co-developed-by: Alex Williamson <alex.williamson@redhat.com> Link: https://lore.kernel.org/r/20210817180500.1253-5-ameynarkhede03@gmail.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
2021-04-28PCI/sysfs: Convert "reset" to static attributeKrzysztof Wilczyński1-0/+2
The "reset" sysfs attribute allows for resetting a PCI function. Previously it was dynamically created either by pci_bus_add_device() or the pci_sysfs_init() initcall, but since it doesn't need to be created or removed dynamically, we can use a static attribute so the device model takes care of addition and removal automatically. Convert "reset" to a static attribute and use the .is_visible() callback to check whether the device supports reset. Clear reset_fn in pci_stop_dev() instead of pci_remove_capabilities_sysfs() since we no longer explicitly remove the "reset" sysfs file. [bhelgaas: commit log] Suggested-by: Oliver O'Halloran <oohall@gmail.com> Link: https://lore.kernel.org/r/20210416205856.3234481-4-kw@linux.com Signed-off-by: Krzysztof Wilczyński <kw@linux.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2020-05-15PCI: Fix pci_host_bridge struct device release/free handlingRob Herring1-1/+1
The PCI code has several paths where the struct pci_host_bridge is freed directly. This is wrong because it contains a struct device which is refcounted and should be freed using put_device(). This can result in use-after-free errors. I think this problem has existed since 2012 with commit 7b5436635800 ("PCI: add generic device into pci_host_bridge struct"). It generally hasn't mattered as most host bridge drivers are still built-in and can't unbind. The problem is a struct device should never be freed directly once device_initialize() is called and a ref is held, but that doesn't happen until pci_register_host_bridge(). There's then a window between allocating the host bridge and pci_register_host_bridge() where kfree should be used. This is fragile and requires callers to do the right thing. To fix this, we need to split device_register() into device_initialize() and device_add() calls, so that the host bridge struct is always freed by using a put_device(). devm_pci_alloc_host_bridge() is using devm_kzalloc() to allocate struct pci_host_bridge which will be freed directly. Instead, we can use a custom devres action to call put_device(). Link: https://lore.kernel.org/r/20200513223859.11295-2-robh@kernel.org Reported-by: Anders Roxell <anders.roxell@linaro.org> Tested-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Rob Herring <robh@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
2018-09-18PCI/ASPM: Fix link_state teardown on device removalLukas Wunner1-3/+1
Upon removal of the last device on a bus, the link_state of the bridge leading to that bus is sought to be torn down by having pci_stop_dev() call pcie_aspm_exit_link_state(). When ASPM was originally introduced by commit 7d715a6c1ae5 ("PCI: add PCI Express ASPM support"), it determined whether the device being removed is the last one by calling list_empty() on the bridge's subordinate devices list. That didn't work because the device is only removed from the list slightly later in pci_destroy_dev(). Commit 3419c75e15f8 ("PCI: properly clean up ASPM link state on device remove") attempted to fix it by calling list_is_last(), but that's not correct either because it checks whether the device is at the *end* of the list, not whether it's the last one *left* in the list. If the user removes the device which happens to be at the end of the list via sysfs but other devices are preceding the device in the list, the link_state is torn down prematurely. The real fix is to move the invocation of pcie_aspm_exit_link_state() to pci_destroy_dev() and reinstate the call to list_empty(). Remove a duplicate check for dev->bus->self because pcie_aspm_exit_link_state() already contains an identical check. Fixes: 7d715a6c1ae5 ("PCI: add PCI Express ASPM support") Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: stable@vger.kernel.org # v2.6.26
2018-08-15Merge branch 'pci/aspm'Bjorn Helgaas1-1/+0
- Use sysfs_match_string() to simplify ASPM sysfs parsing (Andy Shevchenko) - Remove unnecessary includes of <linux/pci-aspm.h> (Bjorn Helgaas) * pci/aspm: PCI: Remove unnecessary include of <linux/pci-aspm.h> iwlwifi: Remove unnecessary include of <linux/pci-aspm.h> ath9k: Remove unnecessary include of <linux/pci-aspm.h> igb: Remove unnecessary include of <linux/pci-aspm.h> PCI/ASPM: Convert to use sysfs_match_string() helper
2018-08-06PCI: Remove unnecessary include of <linux/pci-aspm.h>Bjorn Helgaas1-1/+0
Several PCI core files include pci-aspm.h even though they don't need anything provided by that file. Remove the unnecessary includes of it. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Sinan Kaya <okaya@kernel.org>
2018-07-31PCI: Fix is_added/is_busmaster race conditionHari Vyas1-2/+3
When a PCI device is detected, pdev->is_added is set to 1 and proc and sysfs entries are created. When the device is removed, pdev->is_added is checked for one and then device is detached with clearing of proc and sys entries and at end, pdev->is_added is set to 0. is_added and is_busmaster are bit fields in pci_dev structure sharing same memory location. A strange issue was observed with multiple removal and rescan of a PCIe NVMe device using sysfs commands where is_added flag was observed as zero instead of one while removing device and proc,sys entries are not cleared. This causes issue in later device addition with warning message "proc_dir_entry" already registered. Debugging revealed a race condition between the PCI core setting the is_added bit in pci_bus_add_device() and the NVMe driver reset work-queue setting the is_busmaster bit in pci_set_master(). As these fields are not handled atomically, that clears the is_added bit. Move the is_added bit to a separate private flag variable and use atomic functions to set and retrieve the device addition state. This avoids the race because is_added no longer shares a memory location with is_busmaster. Link: https://bugzilla.kernel.org/show_bug.cgi?id=200283 Signed-off-by: Hari Vyas <hari.vyas@broadcom.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de> Acked-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-26PCI: Add SPDX GPL-2.0 when no license was specifiedBjorn Helgaas1-0/+1
b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to files with no license") added SPDX GPL-2.0 to several PCI files that previously contained no license information. Add SPDX GPL-2.0 to all other PCI files that did not contain any license information and hence were under the default GPL version 2 license of the kernel. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-25PCI: Detach driver before procfs & sysfs teardown on device removeAlex Williamson1-1/+1
When removing a device, for example a VF being removed due to SR-IOV teardown, a "soft" hot-unplug via 'echo 1 > remove' in sysfs, or an actual hot-unplug, we first remove the procfs and sysfs attributes for the device before attempting to release the device from any driver bound to it. Unbinding the driver from the device can take time. The device might need to write out data or it might be actively in use. If it's in use by userspace through a vfio driver, the unbind might block until the user releases the device. This leads to a potentially non-trivial amount of time where the device exists, but we've torn down the interfaces that userspace uses to examine devices, for instance lspci might generate this sort of error: pcilib: Cannot open /sys/bus/pci/devices/0000:01:0a.3/config lspci: Unable to read the standard configuration space header of device 0000:01:0a.3 We don't seem to have any dependence on this teardown ordering in the kernel, so let's unbind the driver first, which is also more symmetric with the instantiation of the device in pci_bus_add_device(). Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2016-11-18PCI: Autosense device removal in pci_bridge_d3_update()Lukas Wunner1-1/+1
The algorithm to update the flag indicating whether a bridge may go to D3 makes a few optimizations based on whether the update was caused by the removal of a device on the one hand, versus the addition of a device or the change of its D3cold flags on the other hand. The information whether the update pertains to a removal is currently passed in by the caller, but the function may as well determine that itself by examining the device in question, thereby allowing for a considerable simplification and reduction of the code. Out of several options to determine removal, I've chosen the function device_is_registered() because it's cheap: It merely returns the dev->kobj.state_in_sysfs flag. That flag is set through device_add() when the root bus is scanned and cleared through device_remove(). The call to pci_bridge_d3_update() happens after each of these calls, respectively, so the ordering is correct. No functional change intended. Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-09-14PCI: Fix bridge_d3 update on device removalLukas Wunner1-2/+1
Starting with v4.8, we allow a PCIe port to runtime suspend to D3hot if the port itself and its children satisfy a number of conditions. Once a child is removed, we recheck those conditions in case the removed device was blocking the port from suspending. The rechecking needs to happen *after* the device has been removed from the bus it resides on. Otherwise when walking the port's subordinate bus in pci_bridge_d3_update(), the device being removed would erroneously still be taken into account. However the device is removed from the bus_list in pci_destroy_dev() and we currently recheck *before* that. Fix it. Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend") Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Rafael J. Wysocki <mika.westerberg@linux.intel.com>
2016-06-13PCI: Put PCIe ports into D3 during suspendMika Westerberg1-0/+2
Currently the Linux PCI core does not touch power state of PCI bridges and PCIe ports when system suspend is entered. Leaving them in D0 consumes power unnecessarily and may prevent the CPU from entering deeper C-states. With recent PCIe hardware we can power down the ports to save power given that we take into account few restrictions: - The PCIe port hardware is recent enough, starting from 2015. - Devices connected to PCIe ports are effectively in D3cold once the port is transitioned to D3 (the config space is not accessible anymore and the link may be powered down). - Devices behind the PCIe port need to be allowed to transition to D3cold and back. There is a way both drivers and userspace can forbid this. - If the device behind the PCIe port is capable of waking the system it needs to be able to do so from D3cold. This patch adds a new flag to struct pci_device called 'bridge_d3'. This flag is set and cleared by the PCI core whenever there is a change in power management state of any of the devices behind the PCIe port. When system later on is suspended we only need to check this flag and if it is true transition the port to D3 otherwise we leave it in D0. Also provide override mechanism via command line parameter "pcie_port_pm=[off|force]" that can be used to disable or enable the feature regardless of the BIOS manufacturing date. Tested-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-03-15Merge branch 'pci/resource' into nextBjorn Helgaas1-1/+0
* pci/resource: PCI: Simplify pci_create_attr() control flow PCI: Don't leak memory if sysfs_create_bin_file() fails PCI: Simplify sysfs ROM cleanup PCI: Remove unused IORESOURCE_ROM_COPY and IORESOURCE_ROM_BIOS_COPY MIPS: Loongson 3: Keep CPU physical (not virtual) addresses in shadow ROM resource MIPS: Loongson 3: Use temporary struct resource * to avoid repetition ia64/PCI: Keep CPU physical (not virtual) addresses in shadow ROM resource ia64/PCI: Use ioremap() instead of open-coded equivalent ia64/PCI: Use temporary struct resource * to avoid repetition PCI: Clean up pci_map_rom() whitespace PCI: Remove arch-specific IORESOURCE_ROM_SHADOW size from sysfs PCI: Set ROM shadow location in arch code, not in PCI core PCI: Don't enable/disable ROM BAR if we're using a RAM shadow copy PCI: Don't assign or reassign immutable resources PCI: Mark shadow copy of VGA ROM as IORESOURCE_PCI_FIXED x86/PCI: Mark Broadwell-EP Home Agent & PCU as having non-compliant BARs PCI: Disable IO/MEM decoding for devices with non-compliant BARs
2016-03-12PCI: Remove unused IORESOURCE_ROM_COPY and IORESOURCE_ROM_BIOS_COPYBjorn Helgaas1-1/+0
The IORESOURCE_ROM_COPY and IORESOURCE_ROM_BIOS_COPY bits are unused. Remove them and code that depends on them. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2016-03-09PCI: Add pci_ops.{add,remove}_bus() callbacksThierry Reding1-0/+4
Add pci_ops.{add,remove}_bus() callbacks, which will be called on every newly created bus and when a bus is being removed, respectively. This can be used by drivers to implement driver-specific initialization and teardown of the bus, in addition to the architecture-specifics implemented by the pcibios_add_bus() and the pcibios_remove_bus() functions. Signed-off-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2015-04-08PCI: Export symbols required for loadable host driver modulesRay Jui1-0/+2
Export the following symbols so they can be referenced by a PCI host bridge driver compiled as a kernel loadable module: pci_common_swizzle pci_create_root_bus pci_stop_root_bus pci_remove_root_bus pci_assign_unassigned_bus_resources pci_fixup_irqs Signed-off-by: Ray Jui <rjui@broadcom.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
2014-02-01Revert "PCI: Remove from bus_list and release resources in pci_release_dev()"Rafael J. Wysocki1-0/+17
Revert commit ef83b0781a73 "PCI: Remove from bus_list and release resources in pci_release_dev()" that made some nasty race conditions become possible. For example, if a Thunderbolt link is unplugged and then replugged immediately, the pci_release_dev() resulting from the hot-remove code path may be racing with the hot-add code path which after that commit causes various kinds of breakage to happen (up to and including a hard crash of the whole system). Moreover, the problem that commit ef83b0781a73 attempted to address cannot happen any more after commit 8a4c5c329de7 "PCI: Check parent kobject in pci_destroy_dev()", because pci_destroy_dev() will now return immediately if it has already been executed for the given device. Note, however, that the invocation of msi_remove_pci_irq_vectors() removed by commit ef83b0781a73 from pci_free_resources() along with the other changes made by it is not added back because of subsequent code changes depending on that modification. Fixes: ef83b0781a73 (PCI: Remove from bus_list and release resources in pci_release_dev()) Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-15PCI: Check parent kobject in pci_destroy_dev()Rafael J. Wysocki1-0/+3
If pci_stop_and_remove_bus_device() is run concurrently for a device and its parent bridge via remove_callback(), both code paths attempt to acquire pci_rescan_remove_lock. If the child device removal acquires it first, there will be no problems. However, if the parent bridge removal acquires it first, it will eventually execute pci_destroy_dev() for the child device, but that device object will not be freed yet due to the reference held by the concurrent child removal. Consequently, both pci_stop_bus_device() and pci_remove_bus_device() will be executed for that device unnecessarily and pci_destroy_dev() will see a corrupted list head in that object. Moreover, an excess put_device() will be executed for that device in that case which may lead to a use-after-free in the final kobject_put() done by sysfs_schedule_callback_work(). To avoid that problem, make pci_destroy_dev() check if the device's parent kobject is NULL, which only happens after device_del() has already run for it. Make pci_destroy_dev() return immediately whithout doing anything in that case. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-01-14PCI: Add global pci_lock_rescan_remove()Rafael J. Wysocki1-0/+8
There are multiple PCI device addition and removal code paths that may be run concurrently with the generic PCI bus rescan and device removal that can be triggered via sysfs. If that happens, it may lead to multiple different, potentially dangerous race conditions. The most straightforward way to address those problems is to run the code in question under the same lock that is used by the generic rescan/remove code in pci-sysfs.c. To prepare for those changes, move the definition of the global PCI remove/rescan lock to probe.c and provide global wrappers, pci_lock_rescan_remove() and pci_unlock_rescan_remove(), allowing drivers to manipulate that lock. Also provide pci_stop_and_remove_bus_device_locked() for the callers of pci_stop_and_remove_bus_device() who only need to hold the rescan/remove lock around it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2013-12-19PCI: Remove from bus_list and release resources in pci_release_dev()Yinghai Lu1-19/+0
Previously we removed the pci_dev from the bus_list and released its resources in pci_destroy_dev(). But that's too early: it's possible to call pci_destroy_dev() twice for the same device (e.g., via sysfs), and that will cause an oops when we try to remove it from bus_list the second time. We should remove it from the bus_list only when the last reference to the pci_dev has been released, i.e., in pci_release_dev(). [bhelgaas: changelog] Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2013-12-19PCI: Use device_release_driver() in pci_stop_root_bus()Yinghai Lu1-2/+2
To be consistent with 4bff6749905d ("PCI: Move device_del() from pci_stop_dev() to pci_destroy_dev()", this changes pci_stop_root_bus() to use device_release_driver() instead of device_del(). This also changes pci_remove_root_bus() to use device_unregister() instead of put_device() so it corresponds with the device_register() call in pci_create_root_bus(). [bhelgaas: changelog] Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-12-19PCI: Move device_del() from pci_stop_dev() to pci_destroy_dev()Rafael J. Wysocki1-1/+3
After commit bcdde7e221a8 (sysfs: make __sysfs_remove_dir() recursive) I'm seeing traces analogous to the one below in Thunderbolt testing: WARNING: CPU: 3 PID: 76 at /scratch/rafael/work/linux-pm/fs/sysfs/group.c:214 sysfs_remove_group+0x59/0xe0() sysfs group ffffffff81c6c500 not found for kobject '0000:08' Modules linked in: ... CPU: 3 PID: 76 Comm: kworker/u16:7 Not tainted 3.13.0-rc1+ #76 Hardware name: Acer Aspire S5-391/Venus , BIOS V1.02 05/29/2012 Workqueue: kacpi_hotplug acpi_hotplug_work_fn 0000000000000009 ffff8801644b9ac8 ffffffff816b23bf 0000000000000007 ffff8801644b9b18 ffff8801644b9b08 ffffffff81046607 ffff88016925b800 0000000000000000 ffffffff81c6c500 ffff88016924f928 ffff88016924f800 Call Trace: [<ffffffff816b23bf>] dump_stack+0x4e/0x71 [<ffffffff81046607>] warn_slowpath_common+0x87/0xb0 [<ffffffff810466d1>] warn_slowpath_fmt+0x41/0x50 [<ffffffff811e42ef>] ? sysfs_get_dirent_ns+0x6f/0x80 [<ffffffff811e5389>] sysfs_remove_group+0x59/0xe0 [<ffffffff8149f00b>] dpm_sysfs_remove+0x3b/0x50 [<ffffffff81495818>] device_del+0x58/0x1c0 [<ffffffff814959c8>] device_unregister+0x48/0x60 [<ffffffff813254fe>] pci_remove_bus+0x6e/0x80 [<ffffffff81325548>] pci_remove_bus_device+0x38/0x110 [<ffffffff8132555d>] pci_remove_bus_device+0x4d/0x110 [<ffffffff81325639>] pci_stop_and_remove_bus_device+0x19/0x20 [<ffffffff813418d0>] disable_slot+0x20/0xe0 [<ffffffff81341a38>] acpiphp_check_bridge+0xa8/0xd0 [<ffffffff813427ad>] hotplug_event+0x17d/0x220 [<ffffffff81342880>] hotplug_event_work+0x30/0x70 [<ffffffff8136d665>] acpi_hotplug_work_fn+0x18/0x24 [<ffffffff81061331>] process_one_work+0x261/0x450 [<ffffffff81061a7e>] worker_thread+0x21e/0x370 [<ffffffff81061860>] ? rescuer_thread+0x300/0x300 [<ffffffff81068342>] kthread+0xd2/0xe0 [<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70 [<ffffffff816c19bc>] ret_from_fork+0x7c/0xb0 [<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70 (Mika Westerberg sees them too in his tests). Some investigation documented in kernel bug #65281 led me to the conclusion that the source of the problem is the device_del() in pci_stop_dev() as it now causes the sysfs directory of the device to be removed recursively along with all of its subdirectories. That includes the sysfs directory of the device's subordinate bus (dev->subordinate) and its "power" group. Consequently, when pci_remove_bus() is called for dev->subordinate in pci_remove_bus_device(), it calls device_unregister(&bus->dev), but at this point the sysfs directory of bus->dev doesn't exist any more and its "power" group doesn't exist either. Thus, when dpm_sysfs_remove() called from device_del() tries to remove that group, it triggers the above warning. That indicates a logical mistake in the design of pci_stop_and_remove_bus_device(), which causes bus device objects to be left behind their parents (bridge device objects) and can be fixed by moving the device_del() from pci_stop_dev() into pci_destroy_dev(), so pci_remove_bus() can be called for the device's subordinate bus before the device itself is unregistered from the hierarchy. Still, the driver, if any, should be detached from the device in pci_stop_dev(), so use device_release_driver() directly from there. References: https://bugzilla.kernel.org/show_bug.cgi?id=65281#c6 Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2013-11-14PCI: Fix whitespace, capitalization, and spelling errorsBjorn Helgaas1-1/+1
Fix whitespace, capitalization, and spelling errors. No functional change. I know "busses" is not an error, but "buses" was more common, so I used it consistently. Signed-off-by: Marta Rybczynska <rybczynska@gmail.com> (pci_reset_bridge_secondary_bus()) Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-13PCI: Add pcibios hooks for adding and removing PCI busesJiang Liu1-0/+1
On ACPI-based platforms, the pci_slot driver creates PCI slot devices according to information from ACPI tables by registering an ACPI PCI subdriver. The ACPI PCI subdriver will only be called when creating/ destroying PCI root buses, and it won't be called when hot-plugging P2P bridges. It may cause stale PCI slot devices after hot-removing a P2P bridge if that bridge has associated PCI slots. And the acpiphp driver has the same issue too. This patch introduces two hook points into the PCI core, which will be invoked when creating/destroying PCI buses for PCI host and P2P bridges. They could be used to setup/destroy platform dependent stuff in a unified way, both at boot time and for PCI hotplug operations. Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Signed-off-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Yinghai Lu <yinghai@kernel.org> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Myron Stowe <myron.stowe@redhat.com>
2013-04-13PCI: When removing bus, always remove legacy files & unregisterJiang Liu1-3/+0
We always call device_register() and pci_create_legacy_files() for a new bus before handing out the "struct pci_bus *". Therefore, there's no possiblity of removing the bus with pci_remove_bus() before those calls have been made, so we don't need to check "bus->is_added" before calling pci_remove_legacy_files() and device_unregister(). [bhelgaas: changelog] Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Signed-off-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Yinghai Lu <yinghai@kernel.org> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Toshi Kani <toshi.kani@hp.com>
2013-02-26Merge tag 'pci-v3.9-changes' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci Pull PCI changes from Bjorn Helgaas: "Host bridge hotplug - Major overhaul of ACPI host bridge add/start (Rafael Wysocki, Yinghai Lu) - Major overhaul of PCI/ACPI binding (Rafael Wysocki, Yinghai Lu) - Split out ACPI host bridge and ACPI PCI device hotplug (Yinghai Lu) - Stop caching _PRT and make independent of bus numbers (Yinghai Lu) PCI device hotplug - Clean up cpqphp dead code (Sasha Levin) - Disable ARI unless device and upstream bridge support it (Yijing Wang) - Initialize all hot-added devices (not functions 0-7) (Yijing Wang) Power management - Don't touch ASPM if disabled (Joe Lawrence) - Fix ASPM link state management (Myron Stowe) Miscellaneous - Fix PCI_EXP_FLAGS accessor (Alex Williamson) - Disable Bus Master in pci_device_shutdown (Konstantin Khlebnikov) - Document hotplug resource and MPS parameters (Yijing Wang) - Add accessor for PCIe capabilities (Myron Stowe) - Drop pciehp suspend/resume messages (Paul Bolle) - Make pci_slot built-in only (not a module) (Jiang Liu) - Remove unused PCI/ACPI bind ops (Jiang Liu) - Removed used pci_root_bus (Bjorn Helgaas)" * tag 'pci-v3.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (51 commits) PCI/ACPI: Don't cache _PRT, and don't associate them with bus numbers PCI: Fix PCI Express Capability accessors for PCI_EXP_FLAGS ACPI / PCI: Make pci_slot built-in only, not a module PCI/PM: Clear state_saved during suspend PCI: Use atomic_inc_return() rather than atomic_add_return() PCI: Catch attempts to disable already-disabled devices PCI: Disable Bus Master unconditionally in pci_device_shutdown() PCI: acpiphp: Remove dead code for PCI host bridge hotplug PCI: acpiphp: Create companion ACPI devices before creating PCI devices PCI: Remove unused "rc" in virtfn_add_bus() PCI: pciehp: Drop suspend/resume ENTRY messages PCI/ASPM: Don't touch ASPM if forcibly disabled PCI/ASPM: Deallocate upstream link state even if device is not PCIe PCI: Document MPS parameters pci=pcie_bus_safe, pci=pcie_bus_perf, etc PCI: Document hpiosize= and hpmemsize= resource reservation parameters PCI: Use PCI Express Capability accessor PCI: Introduce accessor to retrieve PCIe Capabilities Register PCI: Put pci_dev in device tree as early as possible PCI: Skip attaching driver in device_add() PCI: acpiphp: Keep driver loaded even if no slots found ...
2013-02-13PCI/PM: Clean up PME state when removing a deviceRafael J. Wysocki1-0/+2
Devices are added to pci_pme_list when drivers use pci_enable_wake() or pci_wake_from_d3(), but they aren't removed from the list unless the driver explicitly disables wakeup. Many drivers never disable wakeup, so their devices remain on the list even after they are removed, e.g., via hotplug. A subsequent PME poll will oops when it tries to touch the device. This patch disables PME# on a device before removing it, which removes the device from pci_pme_list. This is safe even if the device never had PME# enabled. This oops can be triggered by unplugging a Thunderbolt ethernet adapter on a Macbook Pro, as reported by Daniel below. [bhelgaas: changelog] Reference: http://lkml.kernel.org/r/CAMVG2svG21yiM1wkH4_2pen2n+cr2-Zv7TbH3Gj+8MwevZjDbw@mail.gmail.com Reported-and-tested-by: Daniel J Blueman <daniel@quora.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org
2013-01-26PCI: Make device create/destroy logic symmetricJiang Liu1-2/+2
According to device model documentation, the way to create/destroy PCI devices should be symmetric. The rule is to either use 1) device_register()/device_unregister() or 2) device_initialize()/device_add()/device_del()/put_device(). So change PCI core logic to follow the rule and get rid of the redundant pci_dev_get()/pci_dev_put() pair. Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-04PCI: Add pci_stop_and_remove_root_bus()Yinghai Lu1-0/+36
It supports both PCI root bus and PCI bus under PCI bridge. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2012-09-21PCI: Stop all children first, before removing all childrenYinghai Lu1-16/+35
This restores the previous behavior of stopping all child devices before removing any of them. The current SR-IOV design, where removing the PF also drops references on all the VFs, depends on having the VFs continue to exist after having been stopped. [bhelgaas: changelog] Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2012-08-22PCI: Leave normal LIST_POISON in deleted list entriesBjorn Helgaas1-3/+0
list_del() already sets next/prev to LIST_POISON1/LIST_POISON2, so we don't need to do anything special here to prevent further list accesses. Tested-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Yinghai Lu <yinghai@kernel.org>