x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

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 <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 215 insertions, 0 deletions

diff --git a/drivers/bcma/bcma_private.h b/drivers/bcma/bcma_private.h
new file mode 100644
index 000000000..6eded32d1
--- /dev/null
+++ b/drivers/bcma/bcma_private.h
@@ -0,0 +1,215 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_BCMA_PRIVATE_H_
+#define LINUX_BCMA_PRIVATE_H_
+
+#ifndef pr_fmt
+#define pr_fmt(fmt)		KBUILD_MODNAME ": " fmt
+#endif
+
+#include <linux/bcma/bcma.h>
+#include <linux/delay.h>
+
+#define bcma_err(bus, fmt, ...) \
+	dev_err((bus)->dev, "bus%d: " fmt, (bus)->num, ##__VA_ARGS__)
+#define bcma_warn(bus, fmt, ...) \
+	dev_warn((bus)->dev, "bus%d: " fmt, (bus)->num, ##__VA_ARGS__)
+#define bcma_info(bus, fmt, ...) \
+	dev_info((bus)->dev, "bus%d: " fmt, (bus)->num, ##__VA_ARGS__)
+#define bcma_debug(bus, fmt, ...) \
+	dev_dbg((bus)->dev, "bus%d: " fmt, (bus)->num, ##__VA_ARGS__)
+
+struct bcma_bus;
+
+/* main.c */
+bool bcma_wait_value(struct bcma_device *core, u16 reg, u32 mask, u32 value,
+		     int timeout);
+void bcma_prepare_core(struct bcma_bus *bus, struct bcma_device *core);
+void bcma_init_bus(struct bcma_bus *bus);
+void bcma_unregister_cores(struct bcma_bus *bus);
+int bcma_bus_register(struct bcma_bus *bus);
+void bcma_bus_unregister(struct bcma_bus *bus);
+int __init bcma_bus_early_register(struct bcma_bus *bus);
+#ifdef CONFIG_PM
+int bcma_bus_suspend(struct bcma_bus *bus);
+int bcma_bus_resume(struct bcma_bus *bus);
+#endif
+
+/* scan.c */
+void bcma_detect_chip(struct bcma_bus *bus);
+int bcma_bus_scan(struct bcma_bus *bus);
+
+/* sprom.c */
+int bcma_sprom_get(struct bcma_bus *bus);
+
+/* driver_chipcommon.c */
+void bcma_core_chipcommon_early_init(struct bcma_drv_cc *cc);
+void bcma_core_chipcommon_init(struct bcma_drv_cc *cc);
+void bcma_chipco_bcm4331_ext_pa_lines_ctl(struct bcma_drv_cc *cc, bool enable);
+#ifdef CONFIG_BCMA_DRIVER_MIPS
+void bcma_chipco_serial_init(struct bcma_drv_cc *cc);
+#endif /* CONFIG_BCMA_DRIVER_MIPS */
+
+/* driver_chipcommon_b.c */
+int bcma_core_chipcommon_b_init(struct bcma_drv_cc_b *ccb);
+void bcma_core_chipcommon_b_free(struct bcma_drv_cc_b *ccb);
+
+/* driver_chipcommon_pmu.c */
+void bcma_pmu_early_init(struct bcma_drv_cc *cc);
+void bcma_pmu_init(struct bcma_drv_cc *cc);
+u32 bcma_pmu_get_alp_clock(struct bcma_drv_cc *cc);
+u32 bcma_pmu_get_cpu_clock(struct bcma_drv_cc *cc);
+
+/**************************************************
+ * driver_chipcommon_sflash.c
+ **************************************************/
+
+#ifdef CONFIG_BCMA_PFLASH
+extern struct platform_device bcma_pflash_dev;
+int bcma_pflash_init(struct bcma_drv_cc *cc);
+#else
+static inline int bcma_pflash_init(struct bcma_drv_cc *cc)
+{
+	bcma_err(cc->core->bus, "Parallel flash not supported\n");
+	return 0;
+}
+#endif /* CONFIG_BCMA_PFLASH */
+
+#ifdef CONFIG_BCMA_SFLASH
+/* driver_chipcommon_sflash.c */
+int bcma_sflash_init(struct bcma_drv_cc *cc);
+extern struct platform_device bcma_sflash_dev;
+#else
+static inline int bcma_sflash_init(struct bcma_drv_cc *cc)
+{
+	bcma_err(cc->core->bus, "Serial flash not supported\n");
+	return 0;
+}
+#endif /* CONFIG_BCMA_SFLASH */
+
+#ifdef CONFIG_BCMA_NFLASH
+/* driver_chipcommon_nflash.c */
+int bcma_nflash_init(struct bcma_drv_cc *cc);
+extern struct platform_device bcma_nflash_dev;
+#else
+static inline int bcma_nflash_init(struct bcma_drv_cc *cc)
+{
+	bcma_err(cc->core->bus, "NAND flash not supported\n");
+	return 0;
+}
+#endif /* CONFIG_BCMA_NFLASH */
+
+#ifdef CONFIG_BCMA_HOST_PCI
+/* host_pci.c */
+extern int __init bcma_host_pci_init(void);
+extern void __exit bcma_host_pci_exit(void);
+#endif /* CONFIG_BCMA_HOST_PCI */
+
+/* host_soc.c */
+#if defined(CONFIG_BCMA_HOST_SOC) && defined(CONFIG_OF)
+extern int __init bcma_host_soc_register_driver(void);
+extern void __exit bcma_host_soc_unregister_driver(void);
+#else
+static inline int __init bcma_host_soc_register_driver(void)
+{
+	return 0;
+}
+static inline void __exit bcma_host_soc_unregister_driver(void)
+{
+}
+#endif /* CONFIG_BCMA_HOST_SOC && CONFIG_OF */
+
+/* driver_pci.c */
+#ifdef CONFIG_BCMA_DRIVER_PCI
+u32 bcma_pcie_read(struct bcma_drv_pci *pc, u32 address);
+void bcma_core_pci_early_init(struct bcma_drv_pci *pc);
+void bcma_core_pci_init(struct bcma_drv_pci *pc);
+void bcma_core_pci_up(struct bcma_drv_pci *pc);
+void bcma_core_pci_down(struct bcma_drv_pci *pc);
+#else
+static inline void bcma_core_pci_early_init(struct bcma_drv_pci *pc)
+{
+	WARN_ON(pc->core->bus->hosttype == BCMA_HOSTTYPE_PCI);
+}
+static inline void bcma_core_pci_init(struct bcma_drv_pci *pc)
+{
+	/* Initialization is required for PCI hosted bus */
+	WARN_ON(pc->core->bus->hosttype == BCMA_HOSTTYPE_PCI);
+}
+#endif
+
+/* driver_pcie2.c */
+#ifdef CONFIG_BCMA_DRIVER_PCI
+void bcma_core_pcie2_init(struct bcma_drv_pcie2 *pcie2);
+void bcma_core_pcie2_up(struct bcma_drv_pcie2 *pcie2);
+#else
+static inline void bcma_core_pcie2_init(struct bcma_drv_pcie2 *pcie2)
+{
+	/* Initialization is required for PCI hosted bus */
+	WARN_ON(pcie2->core->bus->hosttype == BCMA_HOSTTYPE_PCI);
+}
+#endif
+
+extern int bcma_chipco_watchdog_register(struct bcma_drv_cc *cc);
+
+#ifdef CONFIG_BCMA_DRIVER_PCI_HOSTMODE
+bool bcma_core_pci_is_in_hostmode(struct bcma_drv_pci *pc);
+void bcma_core_pci_hostmode_init(struct bcma_drv_pci *pc);
+#else
+static inline bool bcma_core_pci_is_in_hostmode(struct bcma_drv_pci *pc)
+{
+	return false;
+}
+static inline void bcma_core_pci_hostmode_init(struct bcma_drv_pci *pc)
+{
+}
+#endif /* CONFIG_BCMA_DRIVER_PCI_HOSTMODE */
+
+/**************************************************
+ * driver_mips.c
+ **************************************************/
+
+#ifdef CONFIG_BCMA_DRIVER_MIPS
+unsigned int bcma_core_mips_irq(struct bcma_device *dev);
+void bcma_core_mips_early_init(struct bcma_drv_mips *mcore);
+void bcma_core_mips_init(struct bcma_drv_mips *mcore);
+#else
+static inline unsigned int bcma_core_mips_irq(struct bcma_device *dev)
+{
+	return 0;
+}
+static inline void bcma_core_mips_early_init(struct bcma_drv_mips *mcore)
+{
+}
+static inline void bcma_core_mips_init(struct bcma_drv_mips *mcore)
+{
+}
+#endif
+
+/**************************************************
+ * driver_gmac_cmn.c
+ **************************************************/
+
+#ifdef CONFIG_BCMA_DRIVER_GMAC_CMN
+void bcma_core_gmac_cmn_init(struct bcma_drv_gmac_cmn *gc);
+#else
+static inline void bcma_core_gmac_cmn_init(struct bcma_drv_gmac_cmn *gc)
+{
+}
+#endif
+
+#ifdef CONFIG_BCMA_DRIVER_GPIO
+/* driver_gpio.c */
+int bcma_gpio_init(struct bcma_drv_cc *cc);
+int bcma_gpio_unregister(struct bcma_drv_cc *cc);
+#else
+static inline int bcma_gpio_init(struct bcma_drv_cc *cc)
+{
+	return -ENOTSUPP;
+}
+static inline int bcma_gpio_unregister(struct bcma_drv_cc *cc)
+{
+	return 0;
+}
+#endif /* CONFIG_BCMA_DRIVER_GPIO */
+
+#endif