[PATCH 5.17 715/772] um: Use asm-generic/dma-mapping.h

Greg Kroah-Hartman
2022-06-07T21:46:51Z

From: Johannes Berg <johannes.berg@intel.com>

commit 365719035526e8eda214a1cedb2e1c96e969a0d7 upstream.

If DMA (PCI over virtio) is enabled, then some drivers may
enable CONFIG_DMA_OPS as well, and then we pull in the x86
definition of get_arch_dma_ops(), which uses the dma_ops
symbol, which isn't defined.

Since we don't have real DMA ops nor any kind of IOMMU fix
this in the simplest possible way: pull in the asm-generic
file instead of inheriting the x86 one. It's not clear why
those drivers that do (e.g. VDPA) "select DMA_OPS", and if
they'd even work with this, but chances are nobody will be
wanting to do that anyway, so fixing the build failure is
good enough.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/um/include/asm/Kbuild | 1 +
1 file changed, 1 insertion(+)

--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -4,6 +4,7 @@ generic-y += bug.h
generic-y += compat.h
generic-y += current.h
generic-y += device.h
+generic-y += dma-mapping.h
generic-y += emergency-restart.h
generic-y += exec.h
generic-y += extable.h