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, 68 insertions, 0 deletions

diff --git a/block/partitions/check.h b/block/partitions/check.h
new file mode 100644
index 000000000..b0997467b
--- /dev/null
+++ b/block/partitions/check.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/pagemap.h>
+#include <linux/blkdev.h>
+#include <linux/seq_buf.h>
+#include "../blk.h"
+
+/*
+ * add_gd_partition adds a partitions details to the devices partition
+ * description.
+ */
+struct parsed_partitions {
+	struct gendisk *disk;
+	char name[BDEVNAME_SIZE];
+	struct {
+		sector_t from;
+		sector_t size;
+		int flags;
+		bool has_info;
+		struct partition_meta_info info;
+	} *parts;
+	int next;
+	int limit;
+	bool access_beyond_eod;
+	struct seq_buf pp_buf;
+};
+
+typedef struct {
+	struct folio *v;
+} Sector;
+
+void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p);
+static inline void put_dev_sector(Sector p)
+{
+	folio_put(p.v);
+}
+
+static inline void
+put_partition(struct parsed_partitions *p, int n, sector_t from, sector_t size)
+{
+	if (n < p->limit) {
+		p->parts[n].from = from;
+		p->parts[n].size = size;
+		seq_buf_printf(&p->pp_buf, " %s%d", p->name, n);
+	}
+}
+
+/* detection routines go here in alphabetical order: */
+int adfspart_check_ADFS(struct parsed_partitions *state);
+int adfspart_check_CUMANA(struct parsed_partitions *state);
+int adfspart_check_EESOX(struct parsed_partitions *state);
+int adfspart_check_ICS(struct parsed_partitions *state);
+int adfspart_check_POWERTEC(struct parsed_partitions *state);
+int aix_partition(struct parsed_partitions *state);
+int amiga_partition(struct parsed_partitions *state);
+int atari_partition(struct parsed_partitions *state);
+int cmdline_partition(struct parsed_partitions *state);
+int efi_partition(struct parsed_partitions *state);
+int ibm_partition(struct parsed_partitions *);
+int karma_partition(struct parsed_partitions *state);
+int ldm_partition(struct parsed_partitions *state);
+int mac_partition(struct parsed_partitions *state);
+int msdos_partition(struct parsed_partitions *state);
+int of_partition(struct parsed_partitions *state);
+int osf_partition(struct parsed_partitions *state);
+int sgi_partition(struct parsed_partitions *state);
+int sun_partition(struct parsed_partitions *state);
+int sysv68_partition(struct parsed_partitions *state);
+int ultrix_partition(struct parsed_partitions *state);