The function dax_pmem_probe() in drivers/dax/pmem.c is compiled under the CONFIG_DEV_DAX_PMEM tri-state config option. This config option currently only depends on CONFIG_NVDIMM_DAX, a bool, which means that the following configuration is possible:
CONFIG_LIBNVDIMM=m ... CONFIG_NVDIMM_DAX=y CONFIG_DEV_DAX=y CONFIG_DEV_DAX_PMEM=y With this config LIBNVDIMM is compiled as a module with NVDIMM_DAX=y just meaning that we will compile drivers/nvdimm/dax_devs.c into that module. However, dax_pmem_probe() depends on several symbols defined in drivers/nvdimm/dax_devs.c, which results in the following build errors: drivers/built-in.o: In function `dax_pmem_probe': linux/drivers/dax/pmem.c:70: undefined reference to `to_nd_dax' linux/drivers/dax/pmem.c:74: undefined reference to `nvdimm_namespace_common_probe' linux/drivers/dax/pmem.c:80: undefined reference to `devm_nsio_enable' linux/drivers/dax/pmem.c:81: undefined reference to `nvdimm_setup_pfn' linux/drivers/dax/pmem.c:84: undefined reference to `devm_nsio_disable' linux/drivers/dax/pmem.c:122: undefined reference to `to_nd_region' drivers/built-in.o: In function `dax_pmem_init': linux/drivers/dax/pmem.c:147: undefined reference to `__nd_driver_register' Fix this by making NVDIMM_DAX a tristate. DEV_DAX_PMEM depends on NVDIMM_DAX which depends on LIBNVDIMM. Since they are all now tristates, if LIBNVDIMM is built as a kernel module DEV_DAX_PMEM will be as well. This prevents dax_devs.c from being built as a built-in while its dependencies are in the libnvdimm.ko module. Signed-off-by: Ross Zwisler <[email protected]> Suggested-by: Dan Williams <[email protected]> --- Change from v1: - Made NVDIMM_DAX a tristate instead of adding an extra dependency. (djbw) --- drivers/nvdimm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig index 124c243..8b2b740 100644 --- a/drivers/nvdimm/Kconfig +++ b/drivers/nvdimm/Kconfig @@ -89,7 +89,7 @@ config NVDIMM_PFN Select Y if unsure config NVDIMM_DAX - bool "NVDIMM DAX: Raw access to persistent memory" + tristate "NVDIMM DAX: Raw access to persistent memory" default LIBNVDIMM depends on NVDIMM_PFN help -- 2.9.0
