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, 57 insertions, 0 deletions

diff --git a/io_uring/notif.h b/io_uring/notif.h
new file mode 100644
index 000000000..f3589cfef
--- /dev/null
+++ b/io_uring/notif.h
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/net.h>
+#include <linux/uio.h>
+#include <net/sock.h>
+#include <linux/nospec.h>
+
+#include "rsrc.h"
+
+#define IO_NOTIF_UBUF_FLAGS	(SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN)
+#define IO_NOTIF_SPLICE_BATCH	32
+
+struct io_notif_data {
+	struct file		*file;
+	struct ubuf_info	uarg;
+
+	struct io_notif_data	*next;
+	struct io_notif_data	*head;
+
+	unsigned		account_pages;
+	bool			zc_report;
+	bool			zc_used;
+	bool			zc_copied;
+};
+
+struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx);
+void io_tx_ubuf_complete(struct sk_buff *skb, struct ubuf_info *uarg,
+			 bool success);
+
+static inline struct io_notif_data *io_notif_to_data(struct io_kiocb *notif)
+{
+	return io_kiocb_to_cmd(notif, struct io_notif_data);
+}
+
+static inline void io_notif_flush(struct io_kiocb *notif)
+	__must_hold(&notif->ctx->uring_lock)
+{
+	struct io_notif_data *nd = io_notif_to_data(notif);
+
+	io_tx_ubuf_complete(NULL, &nd->uarg, true);
+}
+
+static inline int io_notif_account_mem(struct io_kiocb *notif, unsigned len)
+{
+	struct io_ring_ctx *ctx = notif->ctx;
+	struct io_notif_data *nd = io_notif_to_data(notif);
+	unsigned nr_pages = (len >> PAGE_SHIFT) + 2;
+	int ret;
+
+	if (ctx->user) {
+		ret = __io_account_mem(ctx->user, nr_pages);
+		if (ret)
+			return ret;
+		nd->account_pages += nr_pages;
+	}
+	return 0;
+}