Commit 9010dbc0 authored by Mikhail Zaslonko's avatar Mikhail Zaslonko Committed by Andrew Morton
Browse files

lib/zlib: DFLTCC support inflate with small window 

There is no hardware control for DFLTCC window size.  After this change,
software and hardware window formats no longer match: the software will
use wbits and wsize, and the hardware will use HB_BITS and HB_SIZE.

Since neither dictionary manipulation nor internal allocation functions
are relevant to kernel zlib and zlib_inflate_workspacesize() always use
MAX_WBITS for window size calculation, only dfltcc_can_inflate() and
dfltcc_inflate() functions are affected by this patch.

This commit is based on:
  https://github.com/zlib-ng/zlib-ng/commit/3eab317

Link: https://lkml.kernel.org/r/20230126131428.1222214-8-zaslonko@linux.ibm.com


Signed-off-by: default avatarMikhail Zaslonko <zaslonko@linux.ibm.com>
Acked-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 9fec9f8e

lib/zlib_dfltcc/dfltcc_inflate.c

+0 −8
Original line number Diff line number Diff line
@@ -22,10 +22,6 @@ int dfltcc_can_inflate( 
            zlib_dfltcc_support == ZLIB_DFLTCC_DEFLATE_ONLY)

        return 0;



    /* Unsupported compression settings */

    if (state->wbits != HB_BITS)

        return 0;



    /* Unsupported hardware */

    return is_bit_set(dfltcc_state->af.fns, DFLTCC_XPND) &&

               is_bit_set(dfltcc_state->af.fmts, DFLTCC_FMT0);
@@ -129,8 +125,6 @@ dfltcc_inflate_action dfltcc_inflate( 
    /* Translate stream to parameter block */

    param->cvt = CVT_ADLER32;

    param->sbb = state->bits;

    param->hl = state->whave; /* Software and hardware history formats match */

    param->ho = (state->write - state->whave) & ((1 << HB_BITS) - 1);

    if (param->hl)

        param->nt = 0; /* Honor history for the first block */

    param->cv = state->check;
@@ -144,8 +138,6 @@ dfltcc_inflate_action dfltcc_inflate( 
    strm->msg = oesc_msg(dfltcc_state->msg, param->oesc);

    state->last = cc == DFLTCC_CC_OK;

    state->bits = param->sbb;

    state->whave = param->hl;

    state->write = (param->ho + param->hl) & ((1 << HB_BITS) - 1);

    state->check = param->cv;

    if (cc == DFLTCC_CC_OP2_CORRUPT && param->oesc != 0) {

        /* Report an error if stream is corrupted */