The if condition in collect_sample: can never be satisfied
because of a logical contradiction. The indicated dead code
may have performed some action; that action will never occur.
Fixes: 94ae8c3fee ("smb: client: compress: LZ77 code improvements cleanup")
Signed-off-by: Advait Dhamorikar <advaitdhamorikar@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Change is_compressible() return type to bool, use WARN_ON_ONCE(1) for
internal errors and return false for those.
Renames:
check_repeated_data -> has_repeated_data
check_ascii_bytes -> is_mostly_ascii (also refactor into a single loop)
calc_shannon_entropy -> has_low_entropy
Also wraps "wreq->Length" in le32_to_cpu() in should_compress() (caught
by sparse).
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Suggested-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Using uninitialized value "bkt" when calling "kfree"
Fixes: 13b68d44990d ("smb: client: compress: LZ77 code improvements cleanup")
Signed-off-by: Qianqiang Liu <qianqiang.liu@163.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
The dst pointer may not be initialized when calling kvfree(dst)
Fixes: 13b68d44990d9 ("smb: client: compress: LZ77 code improvements cleanup")
Signed-off-by: Qianqiang Liu <qianqiang.liu@163.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
- Check data compressibility with some heuristics (copied from
btrfs):
- should_compress() final decision is is_compressible(data)
- Cleanup compress/lz77.h leaving only lz77_compress() exposed:
- Move parts to compress/lz77.c, while removing the rest of it
because they were either unused, used only once, were
implemented wrong (thanks to David Howells for the help)
- Updated the compression parameters (still compatible with
Windows implementation) trading off ~20% compression ratio
for ~40% performance:
- min match len: 3 -> 4
- max distance: 8KiB -> 1KiB
- hash table type: u32 * -> u64 *
Known bugs:
This implementation currently works fine in general, but breaks with
some payloads used during testing. Investigation ongoing, to be
fixed in a next commit.
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Co-developed-by: David Howells <dhowells@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Move SMB3.1.1 compression code into experimental config option,
and fix the compress mount option. Implement unchained LZ77
"plain" compression algorithm as per MS-XCA specification
section "2.3 Plain LZ77 Compression Algorithm Details".
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
