With CONFIG_BTRFS_FS=y and CONFIG_CRYPTO_CRC32C=m, we get: fs/btrfs/super.o: In function `btrfs_mount_root': fs/btrfs/super.c:1557: undefined reference to `crc32c_impl' fs/btrfs/super.o: In function `btrfs_print_mod_info': fs/btrfs/super.c:2348: undefined reference to `crc32c_impl' fs/btrfs/extent-tree.o: In function `btrfs_crc32c': fs/btrfs/ctree.h:2609: undefined reference to `crc32c' fs/btrfs/ctree.h:2609: undefined reference to `crc32c' fs/btrfs/ctree.h:2609: undefined reference to `crc32c' fs/btrfs/dir-item.o: In function `btrfs_name_hash': fs/btrfs/ctree.h:2619: undefined reference to `crc32c' fs/btrfs/ctree.h:2619: undefined reference to `crc32c'
and more. Note that the comment in the offending commit "The module dependency on crc32c is preserved via MODULE_SOFTDEP("pre: crc32c"), which was previously provided by LIBCRC32C config option doing the same." is wrong, since it permits CONFIG_BTRFS_FS=y in combination with CONFIG_CRYPTO_CRC32C=m. Cc: David Sterba <dste...@suse.com> Fixes: d5178578bcd4 ("btrfs: directly call into crypto framework for checksumming") Signed-off-by: Guenter Roeck <li...@roeck-us.net> --- fs/btrfs/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig index 212b4a854f2c..4c80c70597f9 100644 --- a/fs/btrfs/Kconfig +++ b/fs/btrfs/Kconfig @@ -2,6 +2,7 @@ config BTRFS_FS tristate "Btrfs filesystem support" + select LIBCRC32C select CRYPTO select CRYPTO_CRC32C select ZLIB_INFLATE -- 2.7.4