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, 67 insertions, 0 deletions

diff --git a/include/rdma/rdmavt_cq.h b/include/rdma/rdmavt_cq.h
new file mode 100644
index 000000000..1fe2bb5a6
--- /dev/null
+++ b/include/rdma/rdmavt_cq.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
+/*
+ * Copyright(c) 2016 - 2018 Intel Corporation.
+ */
+
+#ifndef DEF_RDMAVT_INCCQ_H
+#define DEF_RDMAVT_INCCQ_H
+
+#include <linux/kthread.h>
+#include <rdma/ib_user_verbs.h>
+#include <rdma/ib_verbs.h>
+
+/*
+ * Define an ib_cq_notify value that is not valid so we know when CQ
+ * notifications are armed.
+ */
+#define RVT_CQ_NONE      (IB_CQ_NEXT_COMP + 1)
+
+/*
+ * Define read macro that apply smp_load_acquire memory barrier
+ * when reading indice of circular buffer that mmaped to user space.
+ */
+#define RDMA_READ_UAPI_ATOMIC(member) smp_load_acquire(&(member).val)
+
+/*
+ * Define write macro that uses smp_store_release memory barrier
+ * when writing indice of circular buffer that mmaped to user space.
+ */
+#define RDMA_WRITE_UAPI_ATOMIC(member, x) smp_store_release(&(member).val, x)
+#include <rdma/rvt-abi.h>
+
+/*
+ * This structure is used to contain the head pointer, tail pointer,
+ * and completion queue entries as a single memory allocation so
+ * it can be mmap'ed into user space.
+ */
+struct rvt_k_cq_wc {
+	u32 head;               /* index of next entry to fill */
+	u32 tail;               /* index of next ib_poll_cq() entry */
+	struct ib_wc kqueue[];
+};
+
+/*
+ * The completion queue structure.
+ */
+struct rvt_cq {
+	struct ib_cq ibcq;
+	struct work_struct comptask;
+	spinlock_t lock; /* protect changes in this struct */
+	u8 notify;
+	u8 triggered;
+	u8 cq_full;
+	int comp_vector_cpu;
+	struct rvt_dev_info *rdi;
+	struct rvt_cq_wc *queue;
+	struct rvt_mmap_info *ip;
+	struct rvt_k_cq_wc *kqueue;
+};
+
+static inline struct rvt_cq *ibcq_to_rvtcq(struct ib_cq *ibcq)
+{
+	return container_of(ibcq, struct rvt_cq, ibcq);
+}
+
+bool rvt_cq_enter(struct rvt_cq *cq, struct ib_wc *entry, bool solicited);
+
+#endif          /* DEF_RDMAVT_INCCQH */