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, 130 insertions, 0 deletions

diff --git a/include/rdma/ib_pma.h b/include/rdma/ib_pma.h
new file mode 100644
index 000000000..44c618203
--- /dev/null
+++ b/include/rdma/ib_pma.h
@@ -0,0 +1,130 @@
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/*
+ * Copyright (c) 2006, 2007, 2008, 2009, 2010 QLogic Corporation.
+ * All rights reserved.
+ * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
+ */
+
+#ifndef IB_PMA_H
+#define IB_PMA_H
+
+#include <rdma/ib_mad.h>
+
+/*
+ * PMA class portinfo capability mask bits
+ */
+#define IB_PMA_CLASS_CAP_ALLPORTSELECT  cpu_to_be16(1 << 8)
+#define IB_PMA_CLASS_CAP_EXT_WIDTH      cpu_to_be16(1 << 9)
+#define IB_PMA_CLASS_CAP_EXT_WIDTH_NOIETF cpu_to_be16(1 << 10)
+#define IB_PMA_CLASS_CAP_XMIT_WAIT      cpu_to_be16(1 << 12)
+
+#define IB_PMA_CLASS_PORT_INFO          cpu_to_be16(0x0001)
+#define IB_PMA_PORT_SAMPLES_CONTROL     cpu_to_be16(0x0010)
+#define IB_PMA_PORT_SAMPLES_RESULT      cpu_to_be16(0x0011)
+#define IB_PMA_PORT_COUNTERS            cpu_to_be16(0x0012)
+#define IB_PMA_PORT_COUNTERS_EXT        cpu_to_be16(0x001D)
+#define IB_PMA_PORT_SAMPLES_RESULT_EXT  cpu_to_be16(0x001E)
+
+struct ib_pma_mad {
+	struct ib_mad_hdr mad_hdr;
+	u8 reserved[40];
+	u8 data[192];
+} __packed;
+
+struct ib_pma_portsamplescontrol {
+	u8 opcode;
+	u8 port_select;
+	u8 tick;
+	u8 counter_width;		/* resv: 7:3, counter width: 2:0 */
+	__be32 counter_mask0_9;		/* 2, 10 3-bit fields */
+	__be16 counter_mask10_14;	/* 1, 5 3-bit fields */
+	u8 sample_mechanisms;
+	u8 sample_status;		/* only lower 2 bits */
+	__be64 option_mask;
+	__be64 vendor_mask;
+	__be32 sample_start;
+	__be32 sample_interval;
+	__be16 tag;
+	__be16 counter_select[15];
+	__be32 reserved1;
+	__be64 samples_only_option_mask;
+	__be32 reserved2[28];
+};
+
+struct ib_pma_portsamplesresult {
+	__be16 tag;
+	__be16 sample_status;   /* only lower 2 bits */
+	__be32 counter[15];
+};
+
+struct ib_pma_portsamplesresult_ext {
+	__be16 tag;
+	__be16 sample_status;   /* only lower 2 bits */
+	__be32 extended_width;  /* only upper 2 bits */
+	__be64 counter[15];
+};
+
+struct ib_pma_portcounters {
+	u8 reserved;
+	u8 port_select;
+	__be16 counter_select;
+	__be16 symbol_error_counter;
+	u8 link_error_recovery_counter;
+	u8 link_downed_counter;
+	__be16 port_rcv_errors;
+	__be16 port_rcv_remphys_errors;
+	__be16 port_rcv_switch_relay_errors;
+	__be16 port_xmit_discards;
+	u8 port_xmit_constraint_errors;
+	u8 port_rcv_constraint_errors;
+	u8 reserved1;
+	u8 link_overrun_errors; /* LocalLink: 7:4, BufferOverrun: 3:0 */
+	__be16 reserved2;
+	__be16 vl15_dropped;
+	__be32 port_xmit_data;
+	__be32 port_rcv_data;
+	__be32 port_xmit_packets;
+	__be32 port_rcv_packets;
+	__be32 port_xmit_wait;
+} __packed;
+
+
+#define IB_PMA_SEL_SYMBOL_ERROR                 cpu_to_be16(0x0001)
+#define IB_PMA_SEL_LINK_ERROR_RECOVERY          cpu_to_be16(0x0002)
+#define IB_PMA_SEL_LINK_DOWNED                  cpu_to_be16(0x0004)
+#define IB_PMA_SEL_PORT_RCV_ERRORS              cpu_to_be16(0x0008)
+#define IB_PMA_SEL_PORT_RCV_REMPHYS_ERRORS      cpu_to_be16(0x0010)
+#define IB_PMA_SEL_PORT_XMIT_DISCARDS           cpu_to_be16(0x0040)
+#define IB_PMA_SEL_LOCAL_LINK_INTEGRITY_ERRORS  cpu_to_be16(0x0200)
+#define IB_PMA_SEL_EXCESSIVE_BUFFER_OVERRUNS    cpu_to_be16(0x0400)
+#define IB_PMA_SEL_PORT_VL15_DROPPED            cpu_to_be16(0x0800)
+#define IB_PMA_SEL_PORT_XMIT_DATA               cpu_to_be16(0x1000)
+#define IB_PMA_SEL_PORT_RCV_DATA                cpu_to_be16(0x2000)
+#define IB_PMA_SEL_PORT_XMIT_PACKETS            cpu_to_be16(0x4000)
+#define IB_PMA_SEL_PORT_RCV_PACKETS             cpu_to_be16(0x8000)
+
+struct ib_pma_portcounters_ext {
+	u8 reserved;
+	u8 port_select;
+	__be16 counter_select;
+	__be32 reserved1;
+	__be64 port_xmit_data;
+	__be64 port_rcv_data;
+	__be64 port_xmit_packets;
+	__be64 port_rcv_packets;
+	__be64 port_unicast_xmit_packets;
+	__be64 port_unicast_rcv_packets;
+	__be64 port_multicast_xmit_packets;
+	__be64 port_multicast_rcv_packets;
+} __packed;
+
+#define IB_PMA_SELX_PORT_XMIT_DATA              cpu_to_be16(0x0001)
+#define IB_PMA_SELX_PORT_RCV_DATA               cpu_to_be16(0x0002)
+#define IB_PMA_SELX_PORT_XMIT_PACKETS           cpu_to_be16(0x0004)
+#define IB_PMA_SELX_PORT_RCV_PACKETS            cpu_to_be16(0x0008)
+#define IB_PMA_SELX_PORT_UNI_XMIT_PACKETS       cpu_to_be16(0x0010)
+#define IB_PMA_SELX_PORT_UNI_RCV_PACKETS        cpu_to_be16(0x0020)
+#define IB_PMA_SELX_PORT_MULTI_XMIT_PACKETS     cpu_to_be16(0x0040)
+#define IB_PMA_SELX_PORT_MULTI_RCV_PACKETS      cpu_to_be16(0x0080)
+
+#endif /* IB_PMA_H */