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, 66 insertions, 0 deletions

diff --git a/io_uring/filetable.h b/io_uring/filetable.h
new file mode 100644
index 000000000..c348233a3
--- /dev/null
+++ b/io_uring/filetable.h
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef IOU_FILE_TABLE_H
+#define IOU_FILE_TABLE_H
+
+#include <linux/io_uring_types.h>
+#include "rsrc.h"
+
+bool io_alloc_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table, unsigned nr_files);
+void io_free_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table);
+
+int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
+			struct file *file, unsigned int file_slot);
+int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file,
+				unsigned int file_slot);
+int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset);
+
+int io_register_file_alloc_range(struct io_ring_ctx *ctx,
+				 struct io_uring_file_index_range __user *arg);
+
+io_req_flags_t io_file_get_flags(struct file *file);
+
+static inline void io_file_bitmap_clear(struct io_file_table *table, int bit)
+{
+	WARN_ON_ONCE(!test_bit(bit, table->bitmap));
+	__clear_bit(bit, table->bitmap);
+	table->alloc_hint = bit;
+}
+
+static inline void io_file_bitmap_set(struct io_file_table *table, int bit)
+{
+	WARN_ON_ONCE(test_bit(bit, table->bitmap));
+	__set_bit(bit, table->bitmap);
+	table->alloc_hint = bit + 1;
+}
+
+#define FFS_NOWAIT		0x1UL
+#define FFS_ISREG		0x2UL
+#define FFS_MASK		~(FFS_NOWAIT|FFS_ISREG)
+
+static inline unsigned int io_slot_flags(struct io_rsrc_node *node)
+{
+
+	return (node->file_ptr & ~FFS_MASK) << REQ_F_SUPPORT_NOWAIT_BIT;
+}
+
+static inline struct file *io_slot_file(struct io_rsrc_node *node)
+{
+	return (struct file *)(node->file_ptr & FFS_MASK);
+}
+
+static inline void io_fixed_file_set(struct io_rsrc_node *node,
+				     struct file *file)
+{
+	node->file_ptr = (unsigned long)file |
+		(io_file_get_flags(file) >> REQ_F_SUPPORT_NOWAIT_BIT);
+}
+
+static inline void io_file_table_set_alloc_range(struct io_ring_ctx *ctx,
+						 unsigned off, unsigned len)
+{
+	ctx->file_alloc_start = off;
+	ctx->file_alloc_end = off + len;
+	ctx->file_table.alloc_hint = ctx->file_alloc_start;
+}
+
+#endif