Re: [PATCH] dm: writecache: add DAX dependency
From: Mikulas Patocka <mpatocka@redhat.com>
Date: 2018-05-30 12:21:30
Also in:
dm-devel, linux-fsdevel, lkml
On Mon, 28 May 2018, Arnd Bergmann wrote:
quoted hunk ↗ jump to hunk
The new dm-writecache driver inconditionally uses the dax subsystem, leading to link errors in some configurations: drivers/md/dm-writecache.o: In function `writecache_ctr': dm-writecache.c:(.text+0x1fdc): undefined reference to `dax_read_lock' dm-writecache.c:(.text+0x2004): undefined reference to `dax_direct_access' dm-writecache.c:(.text+0x21cc): undefined reference to `dax_read_unlock' It seems wrong to require DAX in order to build the writecache driver, but that at least avoids randconfig build errors. Fixes: bb15b431d650 ("dm: add writecache target") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/md/Kconfig | 1 + 1 file changed, 1 insertion(+)diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index 852c7ebe2902..f8ecf2da1edf 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig@@ -338,6 +338,7 @@ config DM_CACHE_SMQ config DM_WRITECACHE tristate "Writecache target" depends on BLK_DEV_DM + depends on DAX ---help--- The writecache target caches writes on persistent memory or SSD. It is intended for databases or other programs that need extremely-- 2.9.0
dm-writecache may be used without DAX in SSD-only mode. So, I'd fix this by changing the code in dm-writecache.c to #if !defined(CONFIG_ARCH_HAS_PMEM_API) || !defined(CONFIG_DAX) #define DM_WRITECACHE_ONLY_SSD #endif Mikulas