From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- drivers/tc/tc-driver.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) create mode 100644 drivers/tc/tc-driver.c (limited to 'drivers/tc/tc-driver.c') diff --git a/drivers/tc/tc-driver.c b/drivers/tc/tc-driver.c new file mode 100644 index 000000000..2f6d14759 --- /dev/null +++ b/drivers/tc/tc-driver.c @@ -0,0 +1,109 @@ +/* + * TURBOchannel driver services. + * + * Copyright (c) 2005 James Simmons + * Copyright (c) 2006 Maciej W. Rozycki + * + * Loosely based on drivers/dio/dio-driver.c and + * drivers/pci/pci-driver.c. + * + * This file is subject to the terms and conditions of the GNU + * General Public License. See the file "COPYING" in the main + * directory of this archive for more details. + */ + +#include +#include +#include + +/** + * tc_register_driver - register a new TC driver + * @drv: the driver structure to register + * + * Adds the driver structure to the list of registered drivers + * Returns a negative value on error, otherwise 0. + * If no error occurred, the driver remains registered even if + * no device was claimed during registration. + */ +int tc_register_driver(struct tc_driver *tdrv) +{ + return driver_register(&tdrv->driver); +} +EXPORT_SYMBOL(tc_register_driver); + +/** + * tc_unregister_driver - unregister a TC driver + * @drv: the driver structure to unregister + * + * Deletes the driver structure from the list of registered TC drivers, + * gives it a chance to clean up by calling its remove() function for + * each device it was responsible for, and marks those devices as + * driverless. + */ +void tc_unregister_driver(struct tc_driver *tdrv) +{ + driver_unregister(&tdrv->driver); +} +EXPORT_SYMBOL(tc_unregister_driver); + +/** + * tc_match_device - tell if a TC device structure has a matching + * TC device ID structure + * @tdrv: the TC driver to earch for matching TC device ID strings + * @tdev: the TC device structure to match against + * + * Used by a driver to check whether a TC device present in the + * system is in its list of supported devices. Returns the matching + * tc_device_id structure or %NULL if there is no match. + */ +static const struct tc_device_id *tc_match_device(const struct tc_driver *tdrv, + struct tc_dev *tdev) +{ + const struct tc_device_id *id = tdrv->id_table; + + if (id) { + while (id->name[0] || id->vendor[0]) { + if (strcmp(tdev->name, id->name) == 0 && + strcmp(tdev->vendor, id->vendor) == 0) + return id; + id++; + } + } + return NULL; +} + +/** + * tc_bus_match - Tell if a device structure has a matching + * TC device ID structure + * @dev: the device structure to match against + * @drv: the device driver to search for matching TC device ID strings + * + * Used by a driver to check whether a TC device present in the + * system is in its list of supported devices. Returns 1 if there + * is a match or 0 otherwise. + */ +static int tc_bus_match(struct device *dev, const struct device_driver *drv) +{ + struct tc_dev *tdev = to_tc_dev(dev); + const struct tc_driver *tdrv = to_tc_driver(drv); + const struct tc_device_id *id; + + id = tc_match_device(tdrv, tdev); + if (id) + return 1; + + return 0; +} + +const struct bus_type tc_bus_type = { + .name = "tc", + .match = tc_bus_match, +}; +EXPORT_SYMBOL(tc_bus_type); + +static int __init tc_driver_init(void) +{ + return bus_register(&tc_bus_type); +} + +postcore_initcall(tc_driver_init); -- cgit v1.3.1