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, 49 insertions, 0 deletions

diff --git a/io_uring/cancel.h b/io_uring/cancel.h
new file mode 100644
index 000000000..1b201a094
--- /dev/null
+++ b/io_uring/cancel.h
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef IORING_CANCEL_H
+#define IORING_CANCEL_H
+
+#include <linux/io_uring_types.h>
+
+struct io_cancel_data {
+	struct io_ring_ctx *ctx;
+	u64 data;
+	struct file *file;
+	u8 opcode;
+	u32 flags;
+	int seq;
+};
+
+int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
+int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags);
+
+int io_try_cancel(struct io_uring_task *tctx, struct io_cancel_data *cd,
+		  unsigned int issue_flags);
+
+int io_sync_cancel(struct io_ring_ctx *ctx, void __user *arg);
+bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd);
+bool io_match_task_safe(struct io_kiocb *head, struct io_uring_task *tctx,
+			bool cancel_all);
+
+bool io_cancel_remove_all(struct io_ring_ctx *ctx, struct io_uring_task *tctx,
+			  struct hlist_head *list, bool cancel_all,
+			  bool (*cancel)(struct io_kiocb *));
+int io_cancel_remove(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
+		     unsigned int issue_flags, struct hlist_head *list,
+		     bool (*cancel)(struct io_kiocb *));
+__cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
+					 struct io_uring_task *tctx,
+					 bool cancel_all, bool is_sqpoll_thread);
+__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
+__cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data);
+
+static inline bool io_cancel_match_sequence(struct io_kiocb *req, int sequence)
+{
+	if (req->cancel_seq_set && sequence == req->work.cancel_seq)
+		return true;
+
+	req->cancel_seq_set = true;
+	req->work.cancel_seq = sequence;
+	return false;
+}
+
+#endif