[PATCH v5 0/4] zram: fix zstd error paths and add parameter validation

From: Haoqin Huang <[email protected]>

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 an error on dict
load failure (currently errors are silently swallowed).

Patch 3 validates dict and level parameters in each backend's
.setup_params(), rejecting unsupported combinations and out-of-range
levels.

Patch 4 resets per-priority params on algorithm change before init.

Changes since v4:
  - Patch 1: merged zstd_setup_params() zstd_release_params() removal;
    reworded commit message
  - Patch 2: removed "zram:" prefix from pr_err (pr_fmt already adds
    it); reworded commit message
  - Patch 3: dropped lz4 U16_MAX upper bound (the library has no
    limit); changed lz4hc lower bound from LZ4HC_MIN_CLEVEL to < 1
    (the library supports levels 1-2); rebased on tree with deflate
    winbits validation
  - Patch 4: moved comp_params_reset() up instead of using a forward
    declaration

v4: https://lore.kernel.org/all/[email protected]/

Haoqin Huang (4):
  zram: do not release zstd global params from error paths
  zram: reject zero-size dictionary
  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     |  8 ++++++++
 drivers/block/zram/backend_deflate.c | 11 +++++++++++
 drivers/block/zram/backend_lz4.c     |  4 ++++
 drivers/block/zram/backend_lz4hc.c   |  4 ++++
 drivers/block/zram/backend_lzo.c     |  8 ++++++++
 drivers/block/zram/backend_lzorle.c  |  8 ++++++++
 drivers/block/zram/backend_zstd.c    |  7 +++++--
 drivers/block/zram/zram_drv.c        | 29 ++++++++++++++++------------
 8 files changed, 65 insertions(+), 14 deletions(-)

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2.43.7