[PATCH -next] btrfs: Select LIBCRC32C again

[Guenter Roeck <linux@roeck-us.net>]

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 <dsterba@suse.com>
Fixes: d5178578bcd4 ("btrfs: directly call into crypto framework for checksumming")
Signed-off-by: Guenter Roeck <linux@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