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, 78 insertions, 0 deletions

diff --git a/include/asm-generic/logic_io.h b/include/asm-generic/logic_io.h
new file mode 100644
index 000000000..8a59b6e56
--- /dev/null
+++ b/include/asm-generic/logic_io.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2021 Intel Corporation
+ * Author: johannes@sipsolutions.net
+ */
+#ifndef _LOGIC_IO_H
+#define _LOGIC_IO_H
+#include <linux/types.h>
+
+/* include this file into asm/io.h */
+
+#ifdef CONFIG_INDIRECT_IOMEM
+
+#ifdef CONFIG_INDIRECT_IOMEM_FALLBACK
+/*
+ * If you want emulated IO memory to fall back to 'normal' IO memory
+ * if a region wasn't registered as emulated, then you need to have
+ * all of the real_* functions implemented.
+ */
+#if !defined(real_ioremap) || !defined(real_iounmap) || \
+    !defined(real_raw_readb) || !defined(real_raw_writeb) || \
+    !defined(real_raw_readw) || !defined(real_raw_writew) || \
+    !defined(real_raw_readl) || !defined(real_raw_writel) || \
+    (defined(CONFIG_64BIT) && \
+     (!defined(real_raw_readq) || !defined(real_raw_writeq))) || \
+    !defined(real_memset_io) || \
+    !defined(real_memcpy_fromio) || \
+    !defined(real_memcpy_toio)
+#error "Must provide fallbacks for real IO memory access"
+#endif /* defined ... */
+#endif /* CONFIG_INDIRECT_IOMEM_FALLBACK */
+
+#define ioremap ioremap
+void __iomem *ioremap(phys_addr_t offset, size_t size);
+
+#define iounmap iounmap
+void iounmap(void volatile __iomem *addr);
+
+#define __raw_readb __raw_readb
+u8 __raw_readb(const volatile void __iomem *addr);
+
+#define __raw_readw __raw_readw
+u16 __raw_readw(const volatile void __iomem *addr);
+
+#define __raw_readl __raw_readl
+u32 __raw_readl(const volatile void __iomem *addr);
+
+#ifdef CONFIG_64BIT
+#define __raw_readq __raw_readq
+u64 __raw_readq(const volatile void __iomem *addr);
+#endif /* CONFIG_64BIT */
+
+#define __raw_writeb __raw_writeb
+void __raw_writeb(u8 value, volatile void __iomem *addr);
+
+#define __raw_writew __raw_writew
+void __raw_writew(u16 value, volatile void __iomem *addr);
+
+#define __raw_writel __raw_writel
+void __raw_writel(u32 value, volatile void __iomem *addr);
+
+#ifdef CONFIG_64BIT
+#define __raw_writeq __raw_writeq
+void __raw_writeq(u64 value, volatile void __iomem *addr);
+#endif /* CONFIG_64BIT */
+
+#define memset_io memset_io
+void memset_io(volatile void __iomem *addr, int value, size_t size);
+
+#define memcpy_fromio memcpy_fromio
+void memcpy_fromio(void *buffer, const volatile void __iomem *addr,
+		   size_t size);
+
+#define memcpy_toio memcpy_toio
+void memcpy_toio(volatile void __iomem *addr, const void *buffer, size_t size);
+
+#endif /* CONFIG_INDIRECT_IOMEM */
+#endif /* _LOGIC_IO_H */