linux-toradex.git/fs/btrfs/zstd.c, branch v5.5

btrfs: compression: inline free_workspace

2019-11-18T11:46:59+00:00

Replace indirect calls to free_workspace by switch and calls to the
specific callbacks. This is mainly to get rid of the indirection due to
spectre vulnerability mitigations.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: compression: inline alloc_workspace

2019-11-18T11:46:58+00:00

Replace indirect calls to alloc_workspace by switch and calls to the
specific callbacks. This is mainly to get rid of the indirection due to
spectre vulnerability mitigations.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: compression: inline put_workspace

2019-11-18T11:46:58+00:00

Similar to get_workspace, majority of the callbacks is trivial, we don't
gain anything by the indirection, so replace them by a switch function.
Trivial callback implementations use the helper.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: compression: inline get_workspace

2019-11-18T11:46:58+00:00

Majority of the callbacks is trivial, we don't gain anything by the
indirection, so replace them by a switch function.

ZLIB needs to adjust level in the callback and ZSTD workspace management
is complex, the rest is call to the helper.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: compression: export alloc/free/get/put callbacks of all algos

2019-11-18T11:46:58+00:00

The indirect calls will be replaced by a switch in compression.c.
(Switch is faster than indirect calls with when Spectre mitigations are
enabled).

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: compression: inline cleanup_workspace_manager

2019-11-18T11:46:57+00:00

Replace loop calling to all algos with a list of direct calls to the
cleanup manager callback. When that becomes trivial it is replaced by
direct call to the helper.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: compression: inline init_workspace_manager

2019-11-18T11:46:57+00:00

Replace loop calling to all algos with a list of direct calls to the
init manager callback. When that becomes trivial it is replaced by
direct call to the helper.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: compression: attach workspace manager to the ops

2019-11-18T11:46:57+00:00

There's a lot of indirection when the generic code calls into
algo-specific callbacks to reach the private workspace manager structure
and back to the generic code.

To simplify that, export the workspace manager for heuristic, LZO and
ZLIB, while ZSTD is going to use it's own manager.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: switch compression callbacks to direct calls

2019-11-18T11:46:57+00:00

The indirect calls bring some overhead due to spectre vulnerability
mitigations. The number of cases is small and below the threshold
(10-20) where indirect call would be better.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: export compression and decompression callbacks

2019-11-18T11:46:56+00:00

Export compress_pages, decompress_bio and decompress callbacks for all
compression algos. The indirect calls will be replaced by a switch.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nikolay Borisov 
Signed-off-by: David Sterba