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, 55 insertions, 0 deletions

diff --git a/include/scsi/scsi_ioctl.h b/include/scsi/scsi_ioctl.h
new file mode 100644
index 000000000..a207c07da
--- /dev/null
+++ b/include/scsi/scsi_ioctl.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _SCSI_IOCTL_H
+#define _SCSI_IOCTL_H 
+
+#define SCSI_IOCTL_SEND_COMMAND 1
+#define SCSI_IOCTL_TEST_UNIT_READY 2
+#define SCSI_IOCTL_BENCHMARK_COMMAND 3
+#define SCSI_IOCTL_SYNC 4			/* Request synchronous parameters */
+#define SCSI_IOCTL_START_UNIT 5
+#define SCSI_IOCTL_STOP_UNIT 6
+/* The door lock/unlock constants are compatible with Sun constants for
+   the cdrom */
+#define SCSI_IOCTL_DOORLOCK 0x5380		/* lock the eject mechanism */
+#define SCSI_IOCTL_DOORUNLOCK 0x5381		/* unlock the mechanism	  */
+
+#define	SCSI_REMOVAL_PREVENT	1
+#define	SCSI_REMOVAL_ALLOW	0
+
+#ifdef __KERNEL__
+
+struct gendisk;
+struct scsi_device;
+struct sg_io_hdr;
+
+/*
+ * Structures used for scsi_ioctl et al.
+ */
+
+typedef struct scsi_ioctl_command {
+	unsigned int inlen;
+	unsigned int outlen;
+	unsigned char data[];
+} Scsi_Ioctl_Command;
+
+typedef struct scsi_idlun {
+	__u32 dev_id;
+	__u32 host_unique_id;
+} Scsi_Idlun;
+
+/* Fibre Channel WWN, port_id struct */
+typedef struct scsi_fctargaddress {
+	__u32 host_port_id;
+	unsigned char host_wwn[8]; // include NULL term.
+} Scsi_FCTargAddress;
+
+int scsi_ioctl_block_when_processing_errors(struct scsi_device *sdev,
+		int cmd, bool ndelay);
+int scsi_ioctl(struct scsi_device *sdev, bool open_for_write, int cmd,
+		void __user *arg);
+int get_sg_io_hdr(struct sg_io_hdr *hdr, const void __user *argp);
+int put_sg_io_hdr(const struct sg_io_hdr *hdr, void __user *argp);
+bool scsi_cmd_allowed(unsigned char *cmd, bool open_for_write);
+
+#endif /* __KERNEL__ */
+#endif /* _SCSI_IOCTL_H */