commit d92576f1167c ("dax: does not work correctly with virtual aliasing caches") prevents DAX from building on architectures with virtually aliased dcache with: depends on !(ARM || MIPS || SPARC) This check is too broad (e.g. recent ARMv7 don't have virtually aliased dcaches), and also misses many other architectures with virtually aliased dcache. This is a regression introduced in the v5.13 Linux kernel where the dax mount option is removed for 32-bit ARMv7 boards which have no dcache aliasing, and therefore should work fine with FS_DAX. This was turned into the following implementation of dax_is_supported() by a preparatory change: return !IS_ENABLED(CONFIG_ARM) && !IS_ENABLED(CONFIG_MIPS) && !IS_ENABLED(CONFIG_SPARC); Use dcache_is_aliasing() instead to figure out whether the environment has aliasing dcaches. Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches") Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Cc: linux-arch@xxxxxxxxxxxxxxx Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx> Cc: Dave Jiang <dave.jiang@xxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: nvdimm@xxxxxxxxxxxxxxx Cc: linux-cxl@xxxxxxxxxxxxxxx Cc: linux-fsdevel@xxxxxxxxxxxxxxx --- include/linux/dax.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/include/linux/dax.h b/include/linux/dax.h index cfc8cd4a3eae..f59e604662e4 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -5,6 +5,7 @@ #include <linux/fs.h> #include <linux/mm.h> #include <linux/radix-tree.h> +#include <linux/cacheinfo.h> typedef unsigned long dax_entry_t; @@ -80,9 +81,7 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, } static inline bool dax_is_supported(void) { - return !IS_ENABLED(CONFIG_ARM) && - !IS_ENABLED(CONFIG_MIPS) && - !IS_ENABLED(CONFIG_SPARC); + return !dcache_is_aliasing(); } #else static inline void *dax_holder(struct dax_device *dax_dev) -- 2.39.2