btrfs: offload compression to hardware accelerators

This patch series applies to:
  https://git.kernel.org/pub/scm/linux/kernel/git/herbert/c...

This series adds support for hardware-accelerated compression and decompression
in BTRFS using the acomp APIs in the Crypto Framework.  While the
implementation is generic and should work with any acomp-compatible
implementation, the initial enablement targets Intel QAT devices.

Supported operations:
  - zlib: compression and decompression (all QAT generations)
  - zstd: compression only (GEN4 and GEN6)

This is a rework of the earlier RFC series [1].

Changes in this series:
  1. Re-enable zlib-deflate in the Crypto API and QAT driver. These were
     removed in [2] due to lack of in-kernel users. This series reverts
     those commits to restore the functionality.

  2. Add compression level support to the acomp framework. The core
     implementation is from Herbert Xu [3]; I've rebased it and
     addressed checkpatch style issues.
     Compression levels are enabled in deflate, zstd, and the QAT driver.

  3. Add compression offload to QAT accelerators in BTRFS using the acomp
     layer enabled with runtime control via sysfs.
     This feature is wrapped in CONFIG_BTRFS_EXPERIMENTAL.

Note that I included to this set also the bug fix `crypto: zstd - fix
double-free in per-CPU stream cleanup`, even if this is already merged
to crypto-2.6. This is just in case someone wants to test the series.

Feedback Requested:
  1. General approach on integration of acomp with BTRFS
  2. Folio-to-scatterlist conversion.
     @Herbert, any thoughts on this? Would it make sense to do it in the
     acomp layer instead?
  3. Compression level changes.
  4. Offload threshold strategy. Should acomp implementations report
     optimal data size thresholds, possibly per compression level and
     direction?
  5. Optimizations on the LZ4s to sequences algorithm used for GEN4.
     @Yann, any suggestions on how to improve it?
  5. What benchmarks are required for acceptance?

Performance Results. I'm including here the results from the
**previous implementation**, just to have an idea of the performance.
I still need to formally benchmark the new implementation.

Benchmarked on a dual-socket Intel Xeon Platinum 8470N system:
  - 512GB RAM (16x32GB DDR5 4800 MT/s)
  - 4 NVMe drives (349.3GB Intel SSDPE21K375GA each)
  - 2 QAT 4xxx devices (one per socket, compression-only configuration)

Test: 4 parallel processes writing 50GB each (Silesia corpus) to separate
drives

+---------------------------+---------+---------+---------+---------+
|                           | QAT-L9  | ZSTD-L3 | ZLIB-L3 | LZO-L1  |
+---------------------------+---------+---------+---------+---------+
| Disk Write TPUT (GiB/s)   | 6.5     | 5.2     | 2.2     | 6.5     |
+---------------------------+---------+---------+---------+---------+
| CPU utils %age @208 cores | 4.56%   | 15.67%  | 12.79%  | 19.85%  |
+---------------------------+---------+---------+---------+---------+
| Compression Ratio         | 34%     | 35%     | 37%     | 58%     |
+---------------------------+---------+---------+---------+---------+

Results: QAT zlib-deflate L9 achieves the best throughput with significantly
lower CPU utilization and provides better compression
ratio compared with software zstd-l3, zlib-l3 and lzo. 

Changes since v1:
  - Addressed review comments from previous series.
  - Refactored from zlib-specific to generic acomp implementation.
  - Reworked to support folios instead of pages.
  - Added support for zstd compression.
  - Added runtime enable/disable via sysfs (/sys/fs/btrfs/$UUID/offload_compress).
  - Moved buffer allocations from data path to workspace initialization
  - Added compression level support.

[1] https://lore.kernel.org/all/20240426110941.5456-1-giovann...
[2] https://lore.kernel.org/all/ZO8ULhlJSrJ0Mcsx@gondor.apana...
[3] https://lore.kernel.org/all/cover.1716202860.git.herbert@...

Giovanni Cabiddu (12):
  crypto: zstd - fix double-free in per-CPU stream cleanup
  Revert "crypto: qat - remove unused macros in qat_comp_alg.c"
  Revert "crypto: qat - Remove zlib-deflate"
  crypto: qat - use memcpy_*_sglist() in zlib deflate
  Revert "crypto: testmgr - Remove zlib-deflate"
  crypto: deflate - add support for deflate rfc1950 (zlib)
  crypto: acomp - add NUMA-aware stream allocation
  crypto: deflate - add support for compression levels
  crypto: qat - increase number of preallocated sgl descriptors
  crypto: qat - add support for zstd
  crypto: qat - add support for compression levels
  btrfs: add compression hw-accelerated offload

Herbert Xu (3):
  crypto: scomp - Add setparam interface
  crypto: acomp - Add setparam interface
  crypto: acomp - Add comp_params helpers

Suman Kumar Chakraborty (1):
  crypto: zstd - add support for compression levels

 crypto/842.c                                  |   4 +-
 crypto/acompress.c                            | 133 +++-
 crypto/compress.h                             |   9 +-
 crypto/deflate.c                              | 118 ++-
 crypto/lz4.c                                  |   4 +-
 crypto/lz4hc.c                                |   4 +-
 crypto/lzo-rle.c                              |   4 +-
 crypto/lzo.c                                  |   4 +-
 crypto/scompress.c                            |  43 +-
 crypto/testmgr.c                              |  10 +
 crypto/testmgr.h                              |  75 ++
 crypto/zstd.c                                 |  48 +-
 drivers/crypto/intel/qat/Kconfig              |   1 +
 .../intel/qat/qat_420xx/adf_420xx_hw_data.c   |   1 +
 .../intel/qat/qat_4xxx/adf_4xxx_hw_data.c     |   1 +
 .../intel/qat/qat_6xxx/adf_6xxx_hw_data.c     |  19 +-
 drivers/crypto/intel/qat/qat_common/Makefile  |   1 +
 .../intel/qat/qat_common/adf_accel_devices.h  |   8 +-
 .../intel/qat/qat_common/adf_common_drv.h     |   6 +-
 drivers/crypto/intel/qat/qat_common/adf_dc.c  |   5 +-
 drivers/crypto/intel/qat/qat_common/adf_dc.h  |   3 +-
 .../intel/qat/qat_common/adf_gen2_hw_data.c   |  16 +-
 .../intel/qat/qat_common/adf_gen4_hw_data.c   |  29 +-
 .../crypto/intel/qat/qat_common/adf_init.c    |   6 +-
 .../crypto/intel/qat/qat_common/icp_qat_fw.h  |   7 +
 .../intel/qat/qat_common/icp_qat_fw_comp.h    |   2 +
 .../crypto/intel/qat/qat_common/icp_qat_hw.h  |   3 +-
 drivers/crypto/intel/qat/qat_common/qat_bl.h  |   2 +-
 .../intel/qat/qat_common/qat_comp_algs.c      | 712 +++++++++++++++++-
 .../intel/qat/qat_common/qat_comp_req.h       |  11 +
 .../qat/qat_common/qat_comp_zstd_utils.c      | 120 +++
 .../qat/qat_common/qat_comp_zstd_utils.h      |  13 +
 .../intel/qat/qat_common/qat_compression.c    |  23 +-
 fs/btrfs/Makefile                             |   2 +-
 fs/btrfs/acomp.c                              | 470 ++++++++++++
 fs/btrfs/acomp_workspace.h                    |  61 ++
 fs/btrfs/compression.c                        |  66 ++
 fs/btrfs/compression.h                        |  30 +
 fs/btrfs/disk-io.c                            |   6 +
 fs/btrfs/fs.h                                 |   8 +
 fs/btrfs/sysfs.c                              |  29 +
 fs/btrfs/zlib.c                               |  81 ++
 fs/btrfs/zstd.c                               |  64 ++
 include/crypto/acompress.h                    |  27 +
 include/crypto/internal/acompress.h           |  15 +-
 include/crypto/internal/scompress.h           |  27 +
 46 files changed, 2253 insertions(+), 78 deletions(-)
 create mode 100644 drivers/crypto/intel/qat/qat_common/qat_comp_zstd_utils.c
 create mode 100644 drivers/crypto/intel/qat/qat_common/qat_comp_zstd_utils.h
 create mode 100644 fs/btrfs/acomp.c
 create mode 100644 fs/btrfs/acomp_workspace.h


base-commit: ebbdf6466b30e3b37f3b360826efd21f0633fb9e
-- 
2.51.1