2021-02-26 15:55:33

by Geert Uytterhoeven

Subject: [PATCH v3] f2fs: compress: Allow modular (de)compression algorithms

If F2FS_FS is modular, enabling the compressions options
F2FS_FS_{LZ4,LZ4HZ,LZO,LZORLE,ZSTD} will make the (de)compression
algorithms {LZ4,LZ4HC,LZO,ZSTD}_{,DE}COMPRESS builtin instead of
modular, as the former depend on an intermediate boolean
F2FS_FS_COMPRESSION, which in-turn depends on tristate F2FS_FS.

Indeed, if a boolean symbol A depends directly on a tristate symbol B
and selects another tristate symbol C:

tristate B

tristate C

bool A
depends on B
select C

and B is modular, then C will also be modular.

However, if there is an intermediate boolean D in the dependency chain
between A and B:

tristate B

tristate C

bool D
depends on B

bool A
depends on D
select C

then the modular state won't propagate from B to C, and C will be
builtin instead of modular.

As modular dependency propagation through intermediate symbols is
obscure, fix this in a robust way by moving the selection of tristate
(de)compression algorithms from the boolean compression options to the
tristate main F2FS_FS option.

Signed-off-by: Geert Uytterhoeven <[email protected]>
---
v3:
- Drop redundant selects (F2FS_FS_LZORLE depends on F2FS_FS_LZO),

v2:
- Move the selects to F2FS_FS instead of adding direct dependencies
on F2FS_FS.
---
fs/f2fs/Kconfig | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
index 62e638a49bbf089a..7669de7b49cea189 100644
--- a/fs/f2fs/Kconfig
+++ b/fs/f2fs/Kconfig
@@ -7,6 +7,13 @@ config F2FS_FS
select CRYPTO_CRC32
select F2FS_FS_XATTR if FS_ENCRYPTION
select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
+ select LZ4_COMPRESS if F2FS_FS_LZ4
+ select LZ4_DECOMPRESS if F2FS_FS_LZ4
+ select LZ4HC_COMPRESS if F2FS_FS_LZ4HC
+ select LZO_COMPRESS if F2FS_FS_LZO
+ select LZO_DECOMPRESS if F2FS_FS_LZO
+ select ZSTD_COMPRESS if F2FS_FS_ZSTD
+ select ZSTD_DECOMPRESS if F2FS_FS_ZSTD
help
F2FS is based on Log-structured File System (LFS), which supports
versatile "flash-friendly" features. The design has been focused on
@@ -94,8 +101,6 @@ config F2FS_FS_COMPRESSION
config F2FS_FS_LZO
bool "LZO compression support"
depends on F2FS_FS_COMPRESSION
- select LZO_COMPRESS
- select LZO_DECOMPRESS
default y
help
Support LZO compress algorithm, if unsure, say Y.
@@ -103,8 +108,6 @@ config F2FS_FS_LZO
config F2FS_FS_LZ4
bool "LZ4 compression support"
depends on F2FS_FS_COMPRESSION
- select LZ4_COMPRESS
- select LZ4_DECOMPRESS
default y
help
Support LZ4 compress algorithm, if unsure, say Y.
@@ -113,7 +116,6 @@ config F2FS_FS_LZ4HC
bool "LZ4HC compression support"
depends on F2FS_FS_COMPRESSION
depends on F2FS_FS_LZ4
- select LZ4HC_COMPRESS
default y
help
Support LZ4HC compress algorithm, LZ4HC has compatible on-disk
@@ -122,8 +124,6 @@ config F2FS_FS_LZ4HC
config F2FS_FS_ZSTD
bool "ZSTD compression support"
depends on F2FS_FS_COMPRESSION
- select ZSTD_COMPRESS
- select ZSTD_DECOMPRESS
default y
help
Support ZSTD compress algorithm, if unsure, say Y.
@@ -132,8 +132,6 @@ config F2FS_FS_LZORLE
bool "LZO-RLE compression support"
depends on F2FS_FS_COMPRESSION
depends on F2FS_FS_LZO
- select LZO_COMPRESS
- select LZO_DECOMPRESS
default y
help
Support LZO-RLE compress algorithm, if unsure, say Y.
--
2.25.1

2021-02-26 16:05:25

by Masahiro Yamada

Subject: Re: [PATCH v3] f2fs: compress: Allow modular (de)compression algorithms

On Sat, Feb 27, 2021 at 12:51 AM Geert Uytterhoeven
<[email protected]> wrote:
>
> If F2FS_FS is modular, enabling the compressions options
> F2FS_FS_{LZ4,LZ4HZ,LZO,LZORLE,ZSTD} will make the (de)compression
> algorithms {LZ4,LZ4HC,LZO,ZSTD}_{,DE}COMPRESS builtin instead of
> modular, as the former depend on an intermediate boolean
> F2FS_FS_COMPRESSION, which in-turn depends on tristate F2FS_FS.
>
> Indeed, if a boolean symbol A depends directly on a tristate symbol B
> and selects another tristate symbol C:
>
> tristate B
>
> tristate C
>
> bool A
> depends on B
> select C
>
> and B is modular, then C will also be modular.
>
> However, if there is an intermediate boolean D in the dependency chain
> between A and B:
>
> tristate B
>
> tristate C
>
> bool D
> depends on B
>
> bool A
> depends on D
> select C
>
> then the modular state won't propagate from B to C, and C will be
> builtin instead of modular.
>
> As modular dependency propagation through intermediate symbols is
> obscure, fix this in a robust way by moving the selection of tristate
> (de)compression algorithms from the boolean compression options to the
> tristate main F2FS_FS option.
>
> Signed-off-by: Geert Uytterhoeven <[email protected]>

Reviewed-by: Masahiro Yamada <[email protected]>



> ---
> v3:
> - Drop redundant selects (F2FS_FS_LZORLE depends on F2FS_FS_LZO),
>
> v2:
> - Move the selects to F2FS_FS instead of adding direct dependencies
> on F2FS_FS.
> ---
> fs/f2fs/Kconfig | 16 +++++++---------
> 1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
> index 62e638a49bbf089a..7669de7b49cea189 100644
> --- a/fs/f2fs/Kconfig
> +++ b/fs/f2fs/Kconfig
> @@ -7,6 +7,13 @@ config F2FS_FS
> select CRYPTO_CRC32
> select F2FS_FS_XATTR if FS_ENCRYPTION
> select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
> + select LZ4_COMPRESS if F2FS_FS_LZ4
> + select LZ4_DECOMPRESS if F2FS_FS_LZ4
> + select LZ4HC_COMPRESS if F2FS_FS_LZ4HC
> + select LZO_COMPRESS if F2FS_FS_LZO
> + select LZO_DECOMPRESS if F2FS_FS_LZO
> + select ZSTD_COMPRESS if F2FS_FS_ZSTD
> + select ZSTD_DECOMPRESS if F2FS_FS_ZSTD
> help
> F2FS is based on Log-structured File System (LFS), which supports
> versatile "flash-friendly" features. The design has been focused on
> @@ -94,8 +101,6 @@ config F2FS_FS_COMPRESSION
> config F2FS_FS_LZO
> bool "LZO compression support"
> depends on F2FS_FS_COMPRESSION
> - select LZO_COMPRESS
> - select LZO_DECOMPRESS
> default y
> help
> Support LZO compress algorithm, if unsure, say Y.
> @@ -103,8 +108,6 @@ config F2FS_FS_LZO
> config F2FS_FS_LZ4
> bool "LZ4 compression support"
> depends on F2FS_FS_COMPRESSION
> - select LZ4_COMPRESS
> - select LZ4_DECOMPRESS
> default y
> help
> Support LZ4 compress algorithm, if unsure, say Y.
> @@ -113,7 +116,6 @@ config F2FS_FS_LZ4HC
> bool "LZ4HC compression support"
> depends on F2FS_FS_COMPRESSION
> depends on F2FS_FS_LZ4
> - select LZ4HC_COMPRESS
> default y
> help
> Support LZ4HC compress algorithm, LZ4HC has compatible on-disk
> @@ -122,8 +124,6 @@ config F2FS_FS_LZ4HC
> config F2FS_FS_ZSTD
> bool "ZSTD compression support"
> depends on F2FS_FS_COMPRESSION
> - select ZSTD_COMPRESS
> - select ZSTD_DECOMPRESS
> default y
> help
> Support ZSTD compress algorithm, if unsure, say Y.
> @@ -132,8 +132,6 @@ config F2FS_FS_LZORLE
> bool "LZO-RLE compression support"
> depends on F2FS_FS_COMPRESSION
> depends on F2FS_FS_LZO
> - select LZO_COMPRESS
> - select LZO_DECOMPRESS
> default y
> help
> Support LZO-RLE compress algorithm, if unsure, say Y.
> --
> 2.25.1
>


--
Best Regards
Masahiro Yamada

2021-02-27 01:14:19

by Chao Yu

Subject: Re: [f2fs-dev] [PATCH v3] f2fs: compress: Allow modular (de)compression algorithms

On 2021/2/26 23:51, Geert Uytterhoeven wrote:
> If F2FS_FS is modular, enabling the compressions options
> F2FS_FS_{LZ4,LZ4HZ,LZO,LZORLE,ZSTD} will make the (de)compression
> algorithms {LZ4,LZ4HC,LZO,ZSTD}_{,DE}COMPRESS builtin instead of
> modular, as the former depend on an intermediate boolean
> F2FS_FS_COMPRESSION, which in-turn depends on tristate F2FS_FS.
>
> Indeed, if a boolean symbol A depends directly on a tristate symbol B
> and selects another tristate symbol C:
>
> tristate B
>
> tristate C
>
> bool A
> depends on B
> select C
>
> and B is modular, then C will also be modular.
>
> However, if there is an intermediate boolean D in the dependency chain
> between A and B:
>
> tristate B
>
> tristate C
>
> bool D
> depends on B
>
> bool A
> depends on D
> select C
>
> then the modular state won't propagate from B to C, and C will be
> builtin instead of modular.
>
> As modular dependency propagation through intermediate symbols is
> obscure, fix this in a robust way by moving the selection of tristate
> (de)compression algorithms from the boolean compression options to the
> tristate main F2FS_FS option.
>
> Signed-off-by: Geert Uytterhoeven <[email protected]>

Reviewed-by: Chao Yu <[email protected]>

Thanks,