erofs: move {in,out}pages into struct z_erofs_decompress_req

It seems that all compressors need those two values, so just move
them into the common structure.

`struct z_erofs_lz4_decompress_ctx` can be dropped too.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250305124007.1810731-1-hsiangkao@linux.alibaba.com

fs/erofs/compress.h

@@ -11,6 +11,7 @@
 struct z_erofs_decompress_req {
 	struct super_block *sb;
 	struct page **in, **out;
+	unsigned int inpages, outpages;
 	unsigned short pageofs_in, pageofs_out;
 	unsigned int inputsize, outputsize;
 
@@ -59,7 +60,6 @@ extern const struct z_erofs_decompressor *z_erofs_decomp[];
 
 struct z_erofs_stream_dctx {
 	struct z_erofs_decompress_req *rq;
-	unsigned int inpages, outpages;	/* # of {en,de}coded pages */
 	int no, ni;			/* the current {en,de}coded page # */
 
 	unsigned int avail_out;		/* remaining bytes in the decoded buffer */

fs/erofs/decompressor.c

@@ -9,14 +9,6 @@
 
 #define LZ4_MAX_DISTANCE_PAGES	(DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
 
-struct z_erofs_lz4_decompress_ctx {
-	struct z_erofs_decompress_req *rq;
-	/* # of encoded, decoded pages */
-	unsigned int inpages, outpages;
-	/* decoded block total length (used for in-place decompression) */
-	unsigned int oend;
-};
-
 static int z_erofs_load_lz4_config(struct super_block *sb,
 			    struct erofs_super_block *dsb, void *data, int size)
 {
@@ -55,10 +47,9 @@ static int z_erofs_load_lz4_config(struct super_block *sb,
  * Fill all gaps with bounce pages if it's a sparse page list. Also check if
  * all physical pages are consecutive, which can be seen for moderate CR.
  */
-static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,
+static int z_erofs_lz4_prepare_dstpages(struct z_erofs_decompress_req *rq,
 					struct page **pagepool)
 {
-	struct z_erofs_decompress_req *rq = ctx->rq;
 	struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL };
 	unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES,
 					   BITS_PER_LONG)] = { 0 };
@@ -68,7 +59,7 @@ static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,
 	unsigned int i, j, top;
 
 	top = 0;
-	for (i = j = 0; i < ctx->outpages; ++i, ++j) {
+	for (i = j = 0; i < rq->outpages; ++i, ++j) {
 		struct page *const page = rq->out[i];
 		struct page *victim;
 
@@ -114,36 +105,36 @@ static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,
 	return kaddr ? 1 : 0;
 }
 
-static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx,
+static void *z_erofs_lz4_handle_overlap(struct z_erofs_decompress_req *rq,
 			void *inpage, void *out, unsigned int *inputmargin,
 			int *maptype, bool may_inplace)
 {
-	struct z_erofs_decompress_req *rq = ctx->rq;
-	unsigned int omargin, total, i;
+	unsigned int oend, omargin, total, i;
 	struct page **in;
 	void *src, *tmp;
 
 	if (rq->inplace_io) {
-		omargin = PAGE_ALIGN(ctx->oend) - ctx->oend;
+		oend = rq->pageofs_out + rq->outputsize;
+		omargin = PAGE_ALIGN(oend) - oend;
 		if (rq->partial_decoding || !may_inplace ||
 		    omargin < LZ4_DECOMPRESS_INPLACE_MARGIN(rq->inputsize))
 			goto docopy;
 
-		for (i = 0; i < ctx->inpages; ++i)
-			if (rq->out[ctx->outpages - ctx->inpages + i] !=
+		for (i = 0; i < rq->inpages; ++i)
+			if (rq->out[rq->outpages - rq->inpages + i] !=
 			    rq->in[i])
 				goto docopy;
 		kunmap_local(inpage);
 		*maptype = 3;
-		return out + ((ctx->outpages - ctx->inpages) << PAGE_SHIFT);
+		return out + ((rq->outpages - rq->inpages) << PAGE_SHIFT);
 	}
 
-	if (ctx->inpages <= 1) {
+	if (rq->inpages <= 1) {
 		*maptype = 0;
 		return inpage;
 	}
 	kunmap_local(inpage);
-	src = erofs_vm_map_ram(rq->in, ctx->inpages);
+	src = erofs_vm_map_ram(rq->in, rq->inpages);
 	if (!src)
 		return ERR_PTR(-ENOMEM);
 	*maptype = 1;
@@ -152,7 +143,7 @@ static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx,
 docopy:
 	/* Or copy compressed data which can be overlapped to per-CPU buffer */
 	in = rq->in;
-	src = z_erofs_get_gbuf(ctx->inpages);
+	src = z_erofs_get_gbuf(rq->inpages);
 	if (!src) {
 		DBG_BUGON(1);
 		kunmap_local(inpage);
@@ -197,10 +188,8 @@ int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
 	return 0;
 }
 
-static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
-				      u8 *dst)
+static int z_erofs_lz4_decompress_mem(struct z_erofs_decompress_req *rq, u8 *dst)
 {
-	struct z_erofs_decompress_req *rq = ctx->rq;
 	bool support_0padding = false, may_inplace = false;
 	unsigned int inputmargin;
 	u8 *out, *headpage, *src;
@@ -224,7 +213,7 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
 	}
 
 	inputmargin = rq->pageofs_in;
-	src = z_erofs_lz4_handle_overlap(ctx, headpage, dst, &inputmargin,
+	src = z_erofs_lz4_handle_overlap(rq, headpage, dst, &inputmargin,
 					 &maptype, may_inplace);
 	if (IS_ERR(src))
 		return PTR_ERR(src);
@@ -251,7 +240,7 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
 	if (maptype == 0) {
 		kunmap_local(headpage);
 	} else if (maptype == 1) {
-		vm_unmap_ram(src, ctx->inpages);
+		vm_unmap_ram(src, rq->inpages);
 	} else if (maptype == 2) {
 		z_erofs_put_gbuf(src);
 	} else if (maptype != 3) {
@@ -264,54 +253,42 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
 static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
 				  struct page **pagepool)
 {
-	struct z_erofs_lz4_decompress_ctx ctx;
 	unsigned int dst_maptype;
 	void *dst;
 	int ret;
 
-	ctx.rq = rq;
-	ctx.oend = rq->pageofs_out + rq->outputsize;
-	ctx.outpages = PAGE_ALIGN(ctx.oend) >> PAGE_SHIFT;
-	ctx.inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;
-
 	/* one optimized fast path only for non bigpcluster cases yet */
-	if (ctx.inpages == 1 && ctx.outpages == 1 && !rq->inplace_io) {
+	if (rq->inpages == 1 && rq->outpages == 1 && !rq->inplace_io) {
 		DBG_BUGON(!*rq->out);
 		dst = kmap_local_page(*rq->out);
 		dst_maptype = 0;
-		goto dstmap_out;
-	}
-
-	/* general decoding path which can be used for all cases */
-	ret = z_erofs_lz4_prepare_dstpages(&ctx, pagepool);
-	if (ret < 0) {
-		return ret;
-	} else if (ret > 0) {
-		dst = page_address(*rq->out);
-		dst_maptype = 1;
 	} else {
-		dst = erofs_vm_map_ram(rq->out, ctx.outpages);
-		if (!dst)
-			return -ENOMEM;
-		dst_maptype = 2;
+		/* general decoding path which can be used for all cases */
+		ret = z_erofs_lz4_prepare_dstpages(rq, pagepool);
+		if (ret < 0)
+			return ret;
+		if (ret > 0) {
+			dst = page_address(*rq->out);
+			dst_maptype = 1;
+		} else {
+			dst = erofs_vm_map_ram(rq->out, rq->outpages);
+			if (!dst)
+				return -ENOMEM;
+			dst_maptype = 2;
+		}
 	}
-
-dstmap_out:
-	ret = z_erofs_lz4_decompress_mem(&ctx, dst);
+	ret = z_erofs_lz4_decompress_mem(rq, dst);
 	if (!dst_maptype)
 		kunmap_local(dst);
 	else if (dst_maptype == 2)
-		vm_unmap_ram(dst, ctx.outpages);
+		vm_unmap_ram(dst, rq->outpages);
 	return ret;
 }
 
 static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
 				   struct page **pagepool)
 {
-	const unsigned int nrpages_in =
-		PAGE_ALIGN(rq->pageofs_in + rq->inputsize) >> PAGE_SHIFT;
-	const unsigned int nrpages_out =
-		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
+	const unsigned int nrpages_in = rq->inpages, nrpages_out = rq->outpages;
 	const unsigned int bs = rq->sb->s_blocksize;
 	unsigned int cur = 0, ni = 0, no, pi, po, insz, cnt;
 	u8 *kin;
@@ -373,7 +350,7 @@ int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst,
 	unsigned int j;
 
 	if (!dctx->avail_out) {
-		if (++dctx->no >= dctx->outpages || !rq->outputsize) {
+		if (++dctx->no >= rq->outpages || !rq->outputsize) {
 			erofs_err(sb, "insufficient space for decompressed data");
 			return -EFSCORRUPTED;
 		}
@@ -401,7 +378,7 @@ int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst,
 	}
 
 	if (dctx->inbuf_pos == dctx->inbuf_sz && rq->inputsize) {
-		if (++dctx->ni >= dctx->inpages) {
+		if (++dctx->ni >= rq->inpages) {
 			erofs_err(sb, "invalid compressed data");
 			return -EFSCORRUPTED;
 		}
@@ -434,7 +411,7 @@ int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst,
 		dctx->bounced = true;
 	}
 
-	for (j = dctx->ni + 1; j < dctx->inpages; ++j) {
+	for (j = dctx->ni + 1; j < rq->inpages; ++j) {
 		if (rq->out[dctx->no] != rq->in[j])
 			continue;
 		tmppage = erofs_allocpage(pgpl, rq->gfp);

fs/erofs/decompressor_deflate.c

@@ -101,13 +101,7 @@ static int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
 				      struct page **pgpl)
 {
 	struct super_block *sb = rq->sb;
-	struct z_erofs_stream_dctx dctx = {
-		.rq = rq,
-		.inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT,
-		.outpages = PAGE_ALIGN(rq->pageofs_out + rq->outputsize)
-				>> PAGE_SHIFT,
-		.no = -1, .ni = 0,
-	};
+	struct z_erofs_stream_dctx dctx = { .rq = rq, .no = -1, .ni = 0 };
 	struct z_erofs_deflate *strm;
 	int zerr, err;
 

fs/erofs/decompressor_lzma.c

@@ -150,13 +150,7 @@ static int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
 				   struct page **pgpl)
 {
 	struct super_block *sb = rq->sb;
-	struct z_erofs_stream_dctx dctx = {
-		.rq = rq,
-		.inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT,
-		.outpages = PAGE_ALIGN(rq->pageofs_out + rq->outputsize)
-				>> PAGE_SHIFT,
-		.no = -1, .ni = 0,
-	};
+	struct z_erofs_stream_dctx dctx = { .rq = rq, .no = -1, .ni = 0 };
 	struct xz_buf buf = {};
 	struct z_erofs_lzma *strm;
 	enum xz_ret xz_err;

fs/erofs/decompressor_zstd.c

@@ -139,13 +139,7 @@ static int z_erofs_zstd_decompress(struct z_erofs_decompress_req *rq,
 				   struct page **pgpl)
 {
 	struct super_block *sb = rq->sb;
-	struct z_erofs_stream_dctx dctx = {
-		.rq = rq,
-		.inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT,
-		.outpages = PAGE_ALIGN(rq->pageofs_out + rq->outputsize)
-				>> PAGE_SHIFT,
-		.no = -1, .ni = 0,
-	};
+	struct z_erofs_stream_dctx dctx = { .rq = rq, .no = -1, .ni = 0 };
 	zstd_in_buffer in_buf = { NULL, 0, 0 };
 	zstd_out_buffer out_buf = { NULL, 0, 0 };
 	struct z_erofs_zstd *strm;

fs/erofs/zdata.c

@@ -1284,6 +1284,8 @@ static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, int err)
 					.sb = be->sb,
 					.in = be->compressed_pages,
 					.out = be->decompressed_pages,
+					.inpages = pclusterpages,
+					.outpages = be->nr_pages,
 					.pageofs_in = pcl->pageofs_in,
 					.pageofs_out = pcl->pageofs_out,
 					.inputsize = pcl->pclustersize,