bitmap_parselist evolved from a pretty simple idea for long and now lacks for refactoring. It is not structured, has nested loops and a set of opaque-named variables. All this leads to extremely hard understanding of the code. Once during the optimization of it I missed a scenario which leads to kernel hangup. Tetsuo Handa spotted this and found it simpler to rewrite the code instead fixing it. (Though, that attempt had some flaws.) https://lkml.org/lkml/2018/4/1/93
Things are more complicated than they may be because bitmap_parselist() is part of user interface, and its behavior should not change. In this patchset __bitmap_parselist() is split to a set of smaller functions doing only one thing. Yury Norov (4): bitmap_parselist: don't calculate length of the input string bitmap_parselist: move part of logic to helpers bitmap_parselist: rework input string parser test_bitmap: add testcases for bitmap_parselist lib/bitmap.c | 294 ++++++++++++++++++++++++++++++---------------- lib/test_bitmap.c | 18 ++- 2 files changed, 208 insertions(+), 104 deletions(-) -- 2.17.1
