[PATCH v6 0/5] zram: fix zstd error paths and add parameter validation

[Haoqin Huang <haoqinhuang7@gmail.com>]

From: Haoqin Huang <haoqinhuang@tencent.com>

Patch 1 removes zstd_release_params() from both zstd_create() and
zstd_setup_params() error paths -- the former is a layering violation
in a per-CPU callback, the latter is redundant as zcomp_init() already
calls release_params() on setup failure.

Patch 2 rejects zero-size dictionaries and prints distinct error
messages for sz < 0 (returns the original error code) and sz == 0
("empty file"). Currently errors are silently swallowed.

Patch 3 adds pr_fmt to each backend file so that pr_err() messages
are auto-prefixed with the algorithm name.

Patch 4 validates dict and level parameters in each backend's
.setup_params(), rejecting unsupported combinations and out-of-range
levels.

Patch 5 resets per-priority params on algorithm change before init.

Changes since v5:
  - Patch 2: split pr_err into sz < 0 and sz == 0 branches
  - New patch 3: add pr_fmt to all backends; tweak winbits message;
    add missing SPDX headers to lz4 and lz4hc
  - Patch 4: removed inline algo-name prefixes (now handled by pr_fmt);
    added comment for lz4hc < 1 lower bound; added braces to if
    branches for consistency

v5: https://lore.kernel.org/all/20260803141256.60599-1-haoqinhuang7@gmail.com/

Haoqin Huang (5):
  zram: do not release zstd global params from error paths
  zram: reject zero-size dictionary
  zram: add pr_fmt to backend files
  zram: validate parameters in each backend's setup_params
  zram: reset per-priority params when changing algorithm before init

 drivers/block/zram/backend_842.c     | 10 +++++++++
 drivers/block/zram/backend_deflate.c | 17 ++++++++++++--
 drivers/block/zram/backend_lz4.c     | 10 ++++++++-
 drivers/block/zram/backend_lz4hc.c   | 16 +++++++++++++-
 drivers/block/zram/backend_lzo.c     | 10 +++++++++
 drivers/block/zram/backend_lzorle.c  | 10 +++++++++
 drivers/block/zram/backend_zstd.c    | 11 +++++++---
 drivers/block/zram/zram_drv.c        | 33 ++++++++++++++++++----------
 8 files changed, 98 insertions(+), 19 deletions(-)

-- 
2.43.7