Re: [PATCH v8 3/3] lib: zstd: Upgrade to latest upstream zstd version 1.4.10

Nick Terrell
2021-03-26T23:48:31Z

On Fri, Mar 26, 2021 at 3:02 PM kernel test robot <lkp@intel.com> wrote:
>
> Hi Nick,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on cryptodev/master]
> [also build test WARNING on kdave/for-next f2fs/dev-test linus/master v5.12-rc4 next-20210326]
> [cannot apply to crypto/master kees/for-next/pstore squashfs/master]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url: https://github.com/0day-ci/linux/commits/Nick-Terrell/Update-to-zstd-1-4-10/20210327-031827
> base: https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master
> config: um-allmodconfig (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build):
> # https://github.com/0day-ci/linux/commit/ebbff13fa6a537fb8b3dc6b42c3093f9ce4358f8
> git remote add linux-review https://github.com/0day-ci/linux
> git fetch --no-tags linux-review Nick-Terrell/Update-to-zstd-1-4-10/20210327-031827
> git checkout ebbff13fa6a537fb8b3dc6b42c3093f9ce4358f8
> # save the attached .config to linux build tree
> make W=1 ARCH=um
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
> lib/zstd/compress/zstd_compress_sequences.c:17: warning: Cannot understand * -log2(x / 256) lookup table for x in [0, 256).
> on line 17 - I thought it was a doc line
> lib/zstd/compress/zstd_compress_sequences.c:58: warning: Function parameter or member 'nbSeq' not described in 'ZSTD_useLowProbCount'
> >> lib/zstd/compress/zstd_compress_sequences.c:58: warning: expecting prototype for 1 else we should(). Prototype was for ZSTD_useLowProbCount() instead
> >> lib/zstd/compress/zstd_compress_sequences.c:67: warning: wrong kernel-doc identifier on line:
> * Returns the cost in bytes of encoding the normalized count header.
> lib/zstd/compress/zstd_compress_sequences.c:85: warning: Function parameter or member 'count' not described in 'ZSTD_entropyCost'
> lib/zstd/compress/zstd_compress_sequences.c:85: warning: Function parameter or member 'max' not described in 'ZSTD_entropyCost'
> lib/zstd/compress/zstd_compress_sequences.c:85: warning: Function parameter or member 'total' not described in 'ZSTD_entropyCost'
> >> lib/zstd/compress/zstd_compress_sequences.c:85: warning: expecting prototype for Returns the cost in bits of encoding the distribution described by count(). Prototype was for ZSTD_entropyCost() instead
> lib/zstd/compress/zstd_compress_sequences.c:99: warning: wrong kernel-doc identifier on line:
> * Returns the cost in bits of encoding the distribution in count using ctable.
> lib/zstd/compress/zstd_compress_sequences.c:139: warning: Function parameter or member 'norm' not described in 'ZSTD_crossEntropyCost'
> lib/zstd/compress/zstd_compress_sequences.c:139: warning: Function parameter or member 'accuracyLog' not described in 'ZSTD_crossEntropyCost'
> lib/zstd/compress/zstd_compress_sequences.c:139: warning: Function parameter or member 'count' not described in 'ZSTD_crossEntropyCost'
> lib/zstd/compress/zstd_compress_sequences.c:139: warning: Function parameter or member 'max' not described in 'ZSTD_crossEntropyCost'
> >> lib/zstd/compress/zstd_compress_sequences.c:139: warning: expecting prototype for Returns the cost in bits of encoding the distribution in count using the(). Prototype was for ZSTD_crossEntropyCost() instead
> --
> lib/zstd/compress/zstd_ldm.c:584: warning: Function parameter or member 'rawSeqStore' not described in 'maybeSplitSequence'
> lib/zstd/compress/zstd_ldm.c:584: warning: Function parameter or member 'remaining' not described in 'maybeSplitSequence'
> lib/zstd/compress/zstd_ldm.c:584: warning: Function parameter or member 'minMatch' not described in 'maybeSplitSequence'
> >> lib/zstd/compress/zstd_ldm.c:584: warning: expecting prototype for If the sequence length is longer than remaining then the sequence is split(). Prototype was for maybeSplitSequence() instead
> --
> >> lib/zstd/decompress/zstd_decompress.c:992: warning: wrong kernel-doc identifier on line:
> * Similar to ZSTD_nextSrcSizeToDecompress(), but when when a block input can be streamed,
> --
> lib/zstd/decompress/huf_decompress.c:122: warning: Function parameter or member 'symbol' not described in 'HUF_DEltX1_set4'
> lib/zstd/decompress/huf_decompress.c:122: warning: Function parameter or member 'nbBits' not described in 'HUF_DEltX1_set4'
> >> lib/zstd/decompress/huf_decompress.c:122: warning: expecting prototype for This is used to lay down 4 entries at(). Prototype was for HUF_DEltX1_set4() instead
> --
> >> lib/zstd/compress/zstd_compress.c:128: warning: wrong kernel-doc identifier on line:
> * Clears and frees all of the dictionaries in the CCtx.
> lib/zstd/compress/zstd_compress.c:265: warning: wrong kernel-doc identifier on line:
> * Initializes the cctxParams from params and compressionLevel.
> lib/zstd/compress/zstd_compress.c:289: warning: wrong kernel-doc identifier on line:
> * Sets cctxParams' cParams and fParams from params, but otherwise leaves them alone.
> lib/zstd/compress/zstd_compress.c:910: warning: wrong kernel-doc identifier on line:
> * Initializes the local dict using the requested parameters.
> lib/zstd/compress/zstd_compress.c:1457: warning: wrong kernel-doc identifier on line:
> * Controls, for this matchState reset, whether the tables need to be cleared /
> lib/zstd/compress/zstd_compress.c:1473: warning: cannot understand function prototype: 'typedef enum '
> lib/zstd/compress/zstd_compress.c:5008: warning: Function parameter or member 'cParams' not described in 'ZSTD_dedicatedDictSearch_revertCParams'
> >> lib/zstd/compress/zstd_compress.c:5008: warning: expecting prototype for Reverses the adjustment applied to cparams when enabling dedicated dict(). Prototype was for ZSTD_dedicatedDictSearch_revertCParams() instead
>
>
> vim +58 lib/zstd/compress/zstd_compress_sequences.c
>
> 52
> 53 /**
> 54 * Returns true if we should use ncount=-1 else we should
> 55 * use ncount=1 for low probability symbols instead.
> 56 */
> 57 static unsigned ZSTD_useLowProbCount(size_t const nbSeq)
> > 58 {
> 59 /* Heuristic: This should cover most blocks <= 16K and
> 60 * start to fade out after 16K to about 32K depending on
> 61 * comprssibility.
> 62 */
> 63 return nbSeq >= 2048;
> 64 }
> 65
> 66 /**
> > 67 * Returns the cost in bytes of encoding the normalized count header.
> 68 * Returns an error if any of the helper functions return an error.
> 69 */
> 70 static size_t ZSTD_NCountCost(unsigned const* count, unsigned const max,
> 71 size_t const nbSeq, unsigned const FSELog)
> 72 {
> 73 BYTE wksp[FSE_NCOUNTBOUND];
> 74 S16 norm[MaxSeq + 1];
> 75 const U32 tableLog = FSE_optimalTableLog(FSELog, nbSeq, max);
> 76 FORWARD_IF_ERROR(FSE_normalizeCount(norm, tableLog, count, nbSeq, max, ZSTD_useLowProbCount(nbSeq)), "");
> 77 return FSE_writeNCount(wksp, sizeof(wksp), norm, max, tableLog);
> 78 }
> 79
> 80 /**
> 81 * Returns the cost in bits of encoding the distribution described by count
> 82 * using the entropy bound.
> 83 */
> 84 static size_t ZSTD_entropyCost(unsigned const* count, unsigned const max, size_t const total)
> > 85 {
> 86 unsigned cost = 0;
> 87 unsigned s;
> 88 for (s = 0; s <= max; ++s) {
> 89 unsigned norm = (unsigned)((256 * count[s]) / total);
> 90 if (count[s] != 0 && norm == 0)
> 91 norm = 1;
> 92 assert(count[s] < total);
> 93 cost += count[s] * kInverseProbabilityLog256[norm];
> 94 }
> 95 return cost >> 8;
> 96 }
> 97
> 98 /**
> 99 * Returns the cost in bits of encoding the distribution in count using ctable.
> 100 * Returns an error if ctable cannot represent all the symbols in count.
> 101 */
> 102 size_t ZSTD_fseBitCost(
> 103 FSE_CTable const* ctable,
> 104 unsigned const* count,
> 105 unsigned const max)
> 106 {
> 107 unsigned const kAccuracyLog = 8;
> 108 size_t cost = 0;
> 109 unsigned s;
> 110 FSE_CState_t cstate;
> 111 FSE_initCState(&cstate, ctable);
> 112 if (ZSTD_getFSEMaxSymbolValue(ctable) < max) {
> 113 DEBUGLOG(5, "Repeat FSE_CTable has maxSymbolValue %u < %u",
> 114 ZSTD_getFSEMaxSymbolValue(ctable), max);
> 115 return ERROR(GENERIC);
> 116 }
> 117 for (s = 0; s <= max; ++s) {
> 118 unsigned const tableLog = cstate.stateLog;
> 119 unsigned const badCost = (tableLog + 1) << kAccuracyLog;
> 120 unsigned const bitCost = FSE_bitCost(cstate.symbolTT, tableLog, s, kAccuracyLog);
> 121 if (count[s] == 0)
> 122 continue;
> 123 if (bitCost >= badCost) {
> 124 DEBUGLOG(5, "Repeat FSE_CTable has Prob[%u] == 0", s);
> 125 return ERROR(GENERIC);
> 126 }
> 127 cost += (size_t)count[s] * bitCost;
> 128 }
> 129 return cost >> kAccuracyLog;
> 130 }
> 131
> 132 /**
> 133 * Returns the cost in bits of encoding the distribution in count using the
> 134 * table described by norm. The max symbol support by norm is assumed >= max.
> 135 * norm must be valid for every symbol with non-zero probability in count.
> 136 */
> 137 size_t ZSTD_crossEntropyCost(short const* norm, unsigned accuracyLog,
> 138 unsigned const* count, unsigned const max)
> > 139 {
> 140 unsigned const shift = 8 - accuracyLog;
> 141 size_t cost = 0;
> 142 unsigned s;
> 143 assert(accuracyLog <= 8);
> 144 for (s = 0; s <= max; ++s) {
> 145 unsigned const normAcc = (norm[s] != -1) ? (unsigned)norm[s] : 1;
> 146 unsigned const norm256 = normAcc << shift;
> 147 assert(norm256 > 0);
> 148 assert(norm256 < 256);
> 149 cost += count[s] * kInverseProbabilityLog256[norm256];
> 150 }
> 151 return cost >> 8;
> 152 }
> 153
>

These all seem to be comment style warnings. Since this is code
imported from an upstream project, it doesn't make sense to adhere to
the kernel comment style. The public header `include/linux/zstd.h`
should adhere to the kernel style guide, but not `lib/zstd`.

-Nick

> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org