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 --- net/devres.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 net/devres.c (limited to 'net/devres.c') diff --git a/net/devres.c b/net/devres.c new file mode 100644 index 000000000..5ccf6ca31 --- /dev/null +++ b/net/devres.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * This file contains all networking devres helpers. + */ + +#include +#include +#include + +struct net_device_devres { + struct net_device *ndev; +}; + +static void devm_free_netdev(struct device *dev, void *this) +{ + struct net_device_devres *res = this; + + free_netdev(res->ndev); +} + +struct net_device *devm_alloc_etherdev_mqs(struct device *dev, int sizeof_priv, + unsigned int txqs, unsigned int rxqs) +{ + struct net_device_devres *dr; + + dr = devres_alloc(devm_free_netdev, sizeof(*dr), GFP_KERNEL); + if (!dr) + return NULL; + + dr->ndev = alloc_etherdev_mqs(sizeof_priv, txqs, rxqs); + if (!dr->ndev) { + devres_free(dr); + return NULL; + } + + devres_add(dev, dr); + + return dr->ndev; +} +EXPORT_SYMBOL(devm_alloc_etherdev_mqs); + +static void devm_unregister_netdev(struct device *dev, void *this) +{ + struct net_device_devres *res = this; + + unregister_netdev(res->ndev); +} + +static int netdev_devres_match(struct device *dev, void *this, void *match_data) +{ + struct net_device_devres *res = this; + struct net_device *ndev = match_data; + + return ndev == res->ndev; +} + +/** + * devm_register_netdev - resource managed variant of register_netdev() + * @dev: managing device for this netdev - usually the parent device + * @ndev: device to register + * + * This is a devres variant of register_netdev() for which the unregister + * function will be called automatically when the managing device is + * detached. Note: the net_device used must also be resource managed by + * the same struct device. + */ +int devm_register_netdev(struct device *dev, struct net_device *ndev) +{ + struct net_device_devres *dr; + int ret; + + /* struct net_device must itself be managed. For now a managed netdev + * can only be allocated by devm_alloc_etherdev_mqs() so the check is + * straightforward. + */ + if (WARN_ON(!devres_find(dev, devm_free_netdev, + netdev_devres_match, ndev))) + return -EINVAL; + + dr = devres_alloc(devm_unregister_netdev, sizeof(*dr), GFP_KERNEL); + if (!dr) + return -ENOMEM; + + ret = register_netdev(ndev); + if (ret) { + devres_free(dr); + return ret; + } + + dr->ndev = ndev; + devres_add(ndev->dev.parent, dr); + + return 0; +} +EXPORT_SYMBOL(devm_register_netdev); -- cgit v1.3.1