The DAX implementation relies on the architecture to provide a working copy_user_page() function, as reported by Michael Ellerman's kisskb build bot: fs/dax.c: error: implicit declaration of function 'copy_user_page' [-Werror=implicit-function-declaration]: => 266:2 We already have a list of architectures that are known to be incompatible, but the list is missing ARC and SH at the moment. Further, blackfin and c6x also lack support for this function, but are already excluded because they do not support MMU-based kernels. Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> --- diff --git a/fs/Kconfig b/fs/Kconfig index ec35851e5b71..a24d496787d6 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -36,7 +36,7 @@ source "fs/nilfs2/Kconfig" config FS_DAX bool "Direct Access (DAX) support" depends on MMU - depends on !(ARM || MIPS || SPARC) + depends on !(ARC || ARM || MIPS || SH || SPARC) help Direct Access (DAX) can be used on memory-backed block devices. If the block device supports DAX and the filesystem supports DAX, -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html