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, 44 insertions, 0 deletions

diff --git a/drivers/misc/mei/Makefile b/drivers/misc/mei/Makefile
new file mode 100644
index 000000000..9a6aa3359
--- /dev/null
+++ b/drivers/misc/mei/Makefile
@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2010-2019, Intel Corporation. All rights reserved.
+# Makefile - Intel Management Engine Interface (Intel MEI) Linux driver
+#
+obj-$(CONFIG_INTEL_MEI) += mei.o
+mei-objs := init.o
+mei-objs += hbm.o
+mei-objs += interrupt.o
+mei-objs += client.o
+mei-objs += main.o
+mei-objs += dma-ring.o
+mei-objs += bus.o
+mei-objs += bus-fixup.o
+mei-$(CONFIG_DEBUG_FS) += debugfs.o
+
+obj-$(CONFIG_INTEL_MEI_ME) += mei-me.o
+mei-me-objs := pci-me.o
+mei-me-objs += hw-me.o
+
+obj-$(CONFIG_INTEL_MEI_GSC) += mei-gsc.o
+mei-gsc-objs := gsc-me.o
+
+obj-$(CONFIG_INTEL_MEI_CSC) += mei-csc.o
+mei-csc-objs := pci-csc.o
+
+obj-$(CONFIG_INTEL_MEI_TXE) += mei-txe.o
+mei-txe-objs := pci-txe.o
+mei-txe-objs += hw-txe.o
+
+mei-$(CONFIG_EVENT_TRACING) += mei-trace.o
+CFLAGS_mei-trace.o = -I$(src)
+
+obj-$(CONFIG_INTEL_MEI_HDCP) += hdcp/
+obj-$(CONFIG_INTEL_MEI_PXP) += pxp/
+obj-$(CONFIG_INTEL_MEI_GSC_PROXY) += gsc_proxy/
+obj-$(CONFIG_INTEL_MEI_LB) += mei_lb.o
+
+obj-$(CONFIG_INTEL_MEI_VSC_HW) += mei-vsc-hw.o
+mei-vsc-hw-y := vsc-tp.o
+mei-vsc-hw-y += vsc-fw-loader.o
+
+obj-$(CONFIG_INTEL_MEI_VSC) += mei-vsc.o
+mei-vsc-y := platform-vsc.o