[PATCH] zram: add zstd to the supported algorithms list

[Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>]

Add ZSTD to the list of supported compression algorithms.

Official benchmarks [1]:

Compressor name         Ratio   Compression     Decompress.
zstd 1.1.3 -1           2.877   430 MB/s        1110 MB/s
zlib 1.2.8 -1           2.743   110 MB/s        400 MB/s
brotli 0.5.2 -0         2.708   400 MB/s        430 MB/s
quicklz 1.5.0 -1        2.238   550 MB/s        710 MB/s
lzo1x 2.09 -1           2.108   650 MB/s        830 MB/s
lz4 1.7.5               2.101   720 MB/s        3600 MB/s
snappy 1.1.3            2.091   500 MB/s        1650 MB/s
lzf 3.6 -1              2.077   400 MB/s        860 MB/s

[1] https://github.com/facebook/zstd

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
 drivers/block/zram/zcomp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 5b8992beffec..cc66daec7bbc 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -31,6 +31,9 @@ static const char * const backends[] = {
 #endif
 #if IS_ENABLED(CONFIG_CRYPTO_842)
 	"842",
+#endif
+#if IS_ENABLED(CONFIG_CRYPTO_ZSTD)
+	"zstd",
 #endif
 	NULL
 };
-- 
2.14.1