Build kernel from source. Config with DAX worked with 5.9-rc5, but failed with latest 5.9-rc6 drivers/dax/super.c:325:6: error: redefinition of ‘dax_supported’ 325 | bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, | ^~~~~~~~~~~~~ In file included from drivers/dax/super.c:16: ./include/linux/dax.h:162:20: note: previous definition of ‘dax_supported’ was here 162 | static inline bool dax_supported(struct dax_device *dax_dev, | ^~~~~~~~~~~~~ Disabling it in .config the kernel builds fine. Not sure what changed between rc5 and rc6 to cause this.
It has been reported on lkml mailing list. https://lkml.org/lkml/2020/9/20/403 > The failure is fixed with commit 88b67edd7247 ("dax: Fix compilation for CONFIG_DAX && !CONFIG_FS_DAX"). https://lkml.org/lkml/2020/9/21/1792 Fix is in linux-next but not in mainline yet.
Fix is in mainline.