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https://github.com/torvalds/linux
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erofs: tidy up z_erofs_lz4_decompress
To prepare for the upcoming ztailpacking feature and further cleanups, introduce a unique z_erofs_lz4_decompress_ctx to keep the context, including inpages, outpages and oend, which are frequently used by the lz4 decompressor. No logic changes. Link: https://lore.kernel.org/r/20211228054604.114518-2-hsiangkao@linux.alibaba.com Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
This commit is contained in:
Gao Xiang
parent
469407a3b5
commit
d67aee76d4
1 changed files with 44 additions and 39 deletions
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@ -16,6 +16,14 @@
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#define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize) (((srcsize) >> 8) + 32)
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#endif
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struct z_erofs_lz4_decompress_ctx {
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struct z_erofs_decompress_req *rq;
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/* # of encoded, decoded pages */
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unsigned int inpages, outpages;
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/* decoded block total length (used for in-place decompression) */
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unsigned int oend;
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};
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int z_erofs_load_lz4_config(struct super_block *sb,
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struct erofs_super_block *dsb,
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struct z_erofs_lz4_cfgs *lz4, int size)
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@ -56,11 +64,10 @@ int z_erofs_load_lz4_config(struct super_block *sb,
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* Fill all gaps with bounce pages if it's a sparse page list. Also check if
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* all physical pages are consecutive, which can be seen for moderate CR.
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*/
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static int z_erofs_lz4_prepare_dstpages(struct z_erofs_decompress_req *rq,
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static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,
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struct page **pagepool)
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{
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const unsigned int nr =
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PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
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struct z_erofs_decompress_req *rq = ctx->rq;
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struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL };
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unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES,
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BITS_PER_LONG)] = { 0 };
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@ -70,7 +77,7 @@ static int z_erofs_lz4_prepare_dstpages(struct z_erofs_decompress_req *rq,
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unsigned int i, j, top;
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top = 0;
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for (i = j = 0; i < nr; ++i, ++j) {
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for (i = j = 0; i < ctx->outpages; ++i, ++j) {
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struct page *const page = rq->out[i];
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struct page *victim;
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@ -112,41 +119,36 @@ static int z_erofs_lz4_prepare_dstpages(struct z_erofs_decompress_req *rq,
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return kaddr ? 1 : 0;
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}
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static void *z_erofs_lz4_handle_inplace_io(struct z_erofs_decompress_req *rq,
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static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx,
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void *inpage, unsigned int *inputmargin, int *maptype,
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bool support_0padding)
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{
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unsigned int nrpages_in, nrpages_out;
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unsigned int ofull, oend, inputsize, total, i, j;
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struct z_erofs_decompress_req *rq = ctx->rq;
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unsigned int omargin, total, i, j;
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struct page **in;
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void *src, *tmp;
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inputsize = rq->inputsize;
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nrpages_in = PAGE_ALIGN(inputsize) >> PAGE_SHIFT;
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oend = rq->pageofs_out + rq->outputsize;
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ofull = PAGE_ALIGN(oend);
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nrpages_out = ofull >> PAGE_SHIFT;
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if (rq->inplace_io) {
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omargin = PAGE_ALIGN(ctx->oend) - ctx->oend;
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if (rq->partial_decoding || !support_0padding ||
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ofull - oend < LZ4_DECOMPRESS_INPLACE_MARGIN(inputsize))
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omargin < LZ4_DECOMPRESS_INPLACE_MARGIN(rq->inputsize))
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goto docopy;
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for (i = 0; i < nrpages_in; ++i) {
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for (i = 0; i < ctx->inpages; ++i) {
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DBG_BUGON(rq->in[i] == NULL);
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for (j = 0; j < nrpages_out - nrpages_in + i; ++j)
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for (j = 0; j < ctx->outpages - ctx->inpages + i; ++j)
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if (rq->out[j] == rq->in[i])
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goto docopy;
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}
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}
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if (nrpages_in <= 1) {
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if (ctx->inpages <= 1) {
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*maptype = 0;
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return inpage;
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}
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kunmap_atomic(inpage);
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might_sleep();
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src = erofs_vm_map_ram(rq->in, nrpages_in);
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src = erofs_vm_map_ram(rq->in, ctx->inpages);
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if (!src)
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return ERR_PTR(-ENOMEM);
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*maptype = 1;
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@ -155,7 +157,7 @@ static void *z_erofs_lz4_handle_inplace_io(struct z_erofs_decompress_req *rq,
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docopy:
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/* Or copy compressed data which can be overlapped to per-CPU buffer */
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in = rq->in;
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src = erofs_get_pcpubuf(nrpages_in);
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src = erofs_get_pcpubuf(ctx->inpages);
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if (!src) {
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DBG_BUGON(1);
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kunmap_atomic(inpage);
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@ -182,9 +184,10 @@ static void *z_erofs_lz4_handle_inplace_io(struct z_erofs_decompress_req *rq,
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return src;
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}
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static int z_erofs_lz4_decompress_mem(struct z_erofs_decompress_req *rq,
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static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
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u8 *out)
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{
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struct z_erofs_decompress_req *rq = ctx->rq;
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unsigned int inputmargin;
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u8 *headpage, *src;
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bool support_0padding;
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@ -210,8 +213,8 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_decompress_req *rq,
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}
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rq->inputsize -= inputmargin;
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src = z_erofs_lz4_handle_inplace_io(rq, headpage, &inputmargin,
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&maptype, support_0padding);
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src = z_erofs_lz4_handle_overlap(ctx, headpage, &inputmargin,
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&maptype, support_0padding);
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if (IS_ERR(src))
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return PTR_ERR(src);
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@ -240,9 +243,9 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_decompress_req *rq,
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}
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if (maptype == 0) {
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kunmap_atomic(src);
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kunmap_atomic(headpage);
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} else if (maptype == 1) {
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vm_unmap_ram(src, PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT);
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vm_unmap_ram(src, ctx->inpages);
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} else if (maptype == 2) {
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erofs_put_pcpubuf(src);
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} else {
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@ -255,14 +258,18 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_decompress_req *rq,
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static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
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struct page **pagepool)
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{
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const unsigned int nrpages_out =
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PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
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struct z_erofs_lz4_decompress_ctx ctx;
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unsigned int dst_maptype;
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void *dst;
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int ret;
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ctx.rq = rq;
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ctx.oend = rq->pageofs_out + rq->outputsize;
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ctx.outpages = PAGE_ALIGN(ctx.oend) >> PAGE_SHIFT;
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ctx.inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;
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/* one optimized fast path only for non bigpcluster cases yet */
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if (rq->inputsize <= PAGE_SIZE && nrpages_out == 1 && !rq->inplace_io) {
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if (ctx.inpages == 1 && ctx.outpages == 1 && !rq->inplace_io) {
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DBG_BUGON(!*rq->out);
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dst = kmap_atomic(*rq->out);
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dst_maptype = 0;
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@ -270,27 +277,25 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
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}
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/* general decoding path which can be used for all cases */
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ret = z_erofs_lz4_prepare_dstpages(rq, pagepool);
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if (ret < 0)
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ret = z_erofs_lz4_prepare_dstpages(&ctx, pagepool);
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if (ret < 0) {
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return ret;
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if (ret) {
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} else if (ret > 0) {
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dst = page_address(*rq->out);
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dst_maptype = 1;
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goto dstmap_out;
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} else {
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dst = erofs_vm_map_ram(rq->out, ctx.outpages);
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if (!dst)
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return -ENOMEM;
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dst_maptype = 2;
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}
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dst = erofs_vm_map_ram(rq->out, nrpages_out);
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if (!dst)
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return -ENOMEM;
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dst_maptype = 2;
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dstmap_out:
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ret = z_erofs_lz4_decompress_mem(rq, dst + rq->pageofs_out);
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ret = z_erofs_lz4_decompress_mem(&ctx, dst + rq->pageofs_out);
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if (!dst_maptype)
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kunmap_atomic(dst);
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else if (dst_maptype == 2)
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vm_unmap_ram(dst, nrpages_out);
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vm_unmap_ram(dst, ctx.outpages);
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return ret;
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}
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