Building device mapper with CONFIG_DAX=m now results in a link error: drivers/md/dm.o: In function `dm_put_table_device': dm.c:(.text+0x33c): undefined reference to `put_dax' drivers/md/dm.o: In function `cleanup_mapped_device': dm.c:(.text+0x1054): undefined reference to `kill_dax' dm.c:(.text+0x105c): undefined reference to `put_dax' drivers/md/dm.o: In function `dm_get_table_device': dm.c:(.text+0x2744): undefined reference to `dax_get_by_host' drivers/md/dm-table.o: In function `device_dax_write_cache_enabled': dm-table.c:(.text+0x1030): undefined reference to `dax_write_cache_enabled' drivers/md/dm-table.o: In function `dm_table_set_restrictions': dm-table.c:(.text+0x29b8): undefined reference to `dax_write_cache' This adds a dependency that prevents the invalid configuration, allowing a built-in device mapper only if DAX is either built-in as well, or completely disabled. Fixes: 4de1c562f7e9 ("dax, dm: allow device-mapper to operate without dax support") Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> --- The regression only showed up in linux-next at the start of the merge window. Any idea what happened? --- drivers/md/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index 49287135b86c..5e5a47c5ff82 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -200,6 +200,7 @@ config BLK_DEV_DM_BUILTIN config BLK_DEV_DM tristate "Device mapper support" + depends on DAX || DAX=n select BLK_DEV_DM_BUILTIN ---help--- Device-mapper is a low level volume manager. It works by allowing -- 2.9.0 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel