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, 43 insertions, 0 deletions

diff --git a/drivers/block/Makefile b/drivers/block/Makefile
new file mode 100644
index 000000000..2d8096eb8
--- /dev/null
+++ b/drivers/block/Makefile
@@ -0,0 +1,43 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the kernel block device drivers.
+#
+# 12 June 2000, Christoph Hellwig <hch@infradead.org>
+# Rewritten to use lists instead of if-statements.
+# 
+
+# needed for trace events
+ccflags-y				+= -I$(src)
+
+obj-$(CONFIG_MAC_FLOPPY)	+= swim3.o
+obj-$(CONFIG_BLK_DEV_SWIM)	+= swim_mod.o
+obj-$(CONFIG_BLK_DEV_FD)	+= floppy.o
+obj-$(CONFIG_AMIGA_FLOPPY)	+= amiflop.o
+obj-$(CONFIG_PS3_DISK)		+= ps3disk.o
+obj-$(CONFIG_PS3_VRAM)		+= ps3vram.o
+obj-$(CONFIG_ATARI_FLOPPY)	+= ataflop.o
+obj-$(CONFIG_AMIGA_Z2RAM)	+= z2ram.o
+obj-$(CONFIG_N64CART)		+= n64cart.o
+obj-$(CONFIG_BLK_DEV_RAM)	+= brd.o
+obj-$(CONFIG_BLK_DEV_LOOP)	+= loop.o
+obj-$(CONFIG_SUNVDC)		+= sunvdc.o
+
+obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o
+obj-$(CONFIG_VIRTIO_BLK)	+= virtio_blk.o
+
+obj-$(CONFIG_XEN_BLKDEV_FRONTEND)	+= xen-blkfront.o
+obj-$(CONFIG_XEN_BLKDEV_BACKEND)	+= xen-blkback/
+obj-$(CONFIG_BLK_DEV_DRBD)     += drbd/
+obj-$(CONFIG_BLK_DEV_RBD)     += rbd.o
+obj-$(CONFIG_BLK_DEV_PCIESSD_MTIP32XX)	+= mtip32xx/
+
+obj-$(CONFIG_ZRAM) += zram/
+obj-$(CONFIG_BLK_DEV_RNBD)	+= rnbd/
+
+obj-$(CONFIG_BLK_DEV_NULL_BLK)	+= null_blk/
+obj-$(CONFIG_BLK_DEV_RUST_NULL) += rnull/
+
+obj-$(CONFIG_BLK_DEV_UBLK)			+= ublk_drv.o
+obj-$(CONFIG_BLK_DEV_ZONED_LOOP) += zloop.o
+
+swim_mod-y	:= swim.o swim_asm.o