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, 94 insertions, 0 deletions

diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
new file mode 100644
index 000000000..14aa08662
--- /dev/null
+++ b/drivers/dma/Makefile
@@ -0,0 +1,94 @@
+# SPDX-License-Identifier: GPL-2.0
+#dmaengine debug flags
+subdir-ccflags-$(CONFIG_DMADEVICES_DEBUG)  := -DDEBUG
+subdir-ccflags-$(CONFIG_DMADEVICES_VDEBUG) += -DVERBOSE_DEBUG
+
+#core
+obj-$(CONFIG_DMA_ENGINE) += dmaengine.o
+obj-$(CONFIG_DMA_VIRTUAL_CHANNELS) += virt-dma.o
+obj-$(CONFIG_DMA_ACPI) += acpi-dma.o
+obj-$(CONFIG_DMA_OF) += of-dma.o
+
+#dmatest
+obj-$(CONFIG_DMATEST) += dmatest.o
+
+#devices
+obj-$(CONFIG_ALTERA_MSGDMA) += altera-msgdma.o
+obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o
+obj-$(CONFIG_AMCC_PPC440SPE_ADMA) += ppc4xx/
+obj-$(CONFIG_APPLE_ADMAC) += apple-admac.o
+obj-$(CONFIG_ARM_DMA350) += arm-dma350.o
+obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
+obj-$(CONFIG_AT_XDMAC) += at_xdmac.o
+obj-$(CONFIG_AXI_DMAC) += dma-axi-dmac.o
+obj-$(CONFIG_BCM_SBA_RAID) += bcm-sba-raid.o
+obj-$(CONFIG_DMA_BCM2835) += bcm2835-dma.o
+obj-$(CONFIG_DMA_JZ4780) += dma-jz4780.o
+obj-$(CONFIG_DMA_SA11X0) += sa11x0-dma.o
+obj-$(CONFIG_DMA_SUN4I) += sun4i-dma.o
+obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
+obj-$(CONFIG_DW_AXI_DMAC) += dw-axi-dmac/
+obj-$(CONFIG_DW_DMAC_CORE) += dw/
+obj-$(CONFIG_DW_EDMA) += dw-edma/
+obj-$(CONFIG_EP93XX_DMA) += ep93xx_dma.o
+fsl-edma-trace-$(CONFIG_TRACING) := fsl-edma-trace.o
+CFLAGS_fsl-edma-trace.o := -I$(src)
+obj-$(CONFIG_FSL_DMA) += fsldma.o
+fsl-edma-objs := fsl-edma-main.o fsl-edma-common.o ${fsl-edma-trace-y}
+obj-$(CONFIG_FSL_EDMA) += fsl-edma.o
+mcf-edma-objs := mcf-edma-main.o fsl-edma-common.o ${fsl-edma-trace-y}
+obj-$(CONFIG_MCF_EDMA) += mcf-edma.o
+obj-$(CONFIG_FSL_QDMA) += fsl-qdma.o
+obj-$(CONFIG_FSL_RAID) += fsl_raid.o
+obj-$(CONFIG_HISI_DMA) += hisi_dma.o
+obj-$(CONFIG_HSU_DMA) += hsu/
+obj-$(CONFIG_IMG_MDC_DMA) += img-mdc-dma.o
+obj-$(CONFIG_IMX_DMA) += imx-dma.o
+obj-$(CONFIG_IMX_SDMA) += imx-sdma.o
+obj-$(CONFIG_INTEL_IDMA64) += idma64.o
+obj-$(CONFIG_INTEL_IOATDMA) += ioat/
+obj-y += idxd/
+obj-$(CONFIG_K3_DMA) += k3dma.o
+obj-$(CONFIG_LPC18XX_DMAMUX) += lpc18xx-dmamux.o
+obj-$(CONFIG_LPC32XX_DMAMUX) += lpc32xx-dmamux.o
+obj-$(CONFIG_MILBEAUT_HDMAC) += milbeaut-hdmac.o
+obj-$(CONFIG_MILBEAUT_XDMAC) += milbeaut-xdmac.o
+obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o
+obj-$(CONFIG_MMP_TDMA) += mmp_tdma.o
+obj-$(CONFIG_MOXART_DMA) += moxart-dma.o
+obj-$(CONFIG_MPC512X_DMA) += mpc512x_dma.o
+obj-$(CONFIG_MV_XOR) += mv_xor.o
+obj-$(CONFIG_MV_XOR_V2) += mv_xor_v2.o
+obj-$(CONFIG_MXS_DMA) += mxs-dma.o
+obj-$(CONFIG_NBPFAXI_DMA) += nbpfaxi.o
+obj-$(CONFIG_OWL_DMA) += owl-dma.o
+obj-$(CONFIG_PCH_DMA) += pch_dma.o
+obj-$(CONFIG_PL330_DMA) += pl330.o
+obj-$(CONFIG_PLX_DMA) += plx_dma.o
+obj-$(CONFIG_PPC_BESTCOMM) += bestcomm/
+obj-$(CONFIG_PXA_DMA) += pxa_dma.o
+obj-$(CONFIG_RENESAS_DMA) += sh/
+obj-$(CONFIG_SF_PDMA) += sf-pdma/
+obj-$(CONFIG_SOPHGO_CV1800B_DMAMUX) += cv1800b-dmamux.o
+obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
+obj-$(CONFIG_SPRD_DMA) += sprd-dma.o
+obj-$(CONFIG_SWITCHTEC_DMA) += switchtec_dma.o
+obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
+obj-$(CONFIG_TEGRA186_GPC_DMA) += tegra186-gpc-dma.o
+obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
+obj-$(CONFIG_TEGRA210_ADMA) += tegra210-adma.o
+obj-$(CONFIG_TIMB_DMA) += timb_dma.o
+obj-$(CONFIG_UNIPHIER_MDMAC) += uniphier-mdmac.o
+obj-$(CONFIG_UNIPHIER_XDMAC) += uniphier-xdmac.o
+obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
+obj-$(CONFIG_ST_FDMA) += st_fdma.o
+obj-$(CONFIG_FSL_DPAA2_QDMA) += fsl-dpaa2-qdma/
+obj-$(CONFIG_INTEL_LDMA) += lgm/
+
+obj-y += amd/
+obj-y += loongson/
+obj-y += mediatek/
+obj-y += qcom/
+obj-y += stm32/
+obj-y += ti/
+obj-y += xilinx/