From 5b6e7e120e716231a0bf9ad201438d72473e396d Mon Sep 17 00:00:00 2001 From: Yue Hu Date: Thu, 14 Oct 2021 14:57:44 +0800 Subject: [PATCH] erofs: remove the fast path of per-CPU buffer decompression As Xiang mentioned, such path has no real impact to our current decompression strategy, remove it directly. Also, update the return value of z_erofs_lz4_decompress() to 0 if success to keep consistent with LZMA which will return 0 as well for that case. Link: https://lore.kernel.org/r/20211014065744.1787-1-zbestahu@gmail.com Reviewed-by: Gao Xiang Signed-off-by: Yue Hu Signed-off-by: Gao Xiang --- fs/erofs/decompressor.c | 63 ++++++----------------------------------- 1 file changed, 8 insertions(+), 55 deletions(-) diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c index a5bc4b1b7813..dce06ac61893 100644 --- a/fs/erofs/decompressor.c +++ b/fs/erofs/decompressor.c @@ -242,6 +242,8 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out) if (ret >= 0) memset(out + ret, 0, rq->outputsize - ret); ret = -EIO; + } else { + ret = 0; } if (maptype == 0) { @@ -268,33 +270,6 @@ static struct z_erofs_decompressor decompressors[] = { }, }; -static void copy_from_pcpubuf(struct page **out, const char *dst, - unsigned short pageofs_out, - unsigned int outputsize) -{ - const char *end = dst + outputsize; - const unsigned int righthalf = PAGE_SIZE - pageofs_out; - const char *cur = dst - pageofs_out; - - while (cur < end) { - struct page *const page = *out++; - - if (page) { - char *buf = kmap_atomic(page); - - if (cur >= dst) { - memcpy(buf, cur, min_t(uint, PAGE_SIZE, - end - cur)); - } else { - memcpy(buf + pageofs_out, cur + pageofs_out, - min_t(uint, righthalf, end - cur)); - } - kunmap_atomic(buf); - } - cur += PAGE_SIZE; - } -} - static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq, struct list_head *pagepool) { @@ -305,34 +280,12 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq, void *dst; int ret; - /* two optimized fast paths only for non bigpcluster cases yet */ - if (rq->inputsize <= PAGE_SIZE) { - if (nrpages_out == 1 && !rq->inplace_io) { - DBG_BUGON(!*rq->out); - dst = kmap_atomic(*rq->out); - dst_maptype = 0; - goto dstmap_out; - } - - /* - * For the case of small output size (especially much less - * than PAGE_SIZE), memcpy the decompressed data rather than - * compressed data is preferred. - */ - if (rq->outputsize <= PAGE_SIZE * 7 / 8) { - dst = erofs_get_pcpubuf(1); - if (IS_ERR(dst)) - return PTR_ERR(dst); - - rq->inplace_io = false; - ret = alg->decompress(rq, dst); - if (!ret) - copy_from_pcpubuf(rq->out, dst, rq->pageofs_out, - rq->outputsize); - - erofs_put_pcpubuf(dst); - return ret; - } + /* one optimized fast path only for non bigpcluster cases yet */ + if (rq->inputsize <= PAGE_SIZE && nrpages_out == 1 && !rq->inplace_io) { + DBG_BUGON(!*rq->out); + dst = kmap_atomic(*rq->out); + dst_maptype = 0; + goto dstmap_out; } /* general decoding path which can be used for all cases */