Revert "erofs: support decompress big pcluster for lz4 backend"

This reverts commit 3337f63708.

Reason: Conflicts with next change and doesn't exist upstream

Change-Id: I65fdef31d221f6536254a3dffa3f0b1e871e28ff

fs/erofs/decompressor.c

@@ -123,85 +123,44 @@ static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
 	return kaddr ? 1 : 0;
 }
 
-static void *z_erofs_handle_inplace_io(struct z_erofs_decompress_req *rq,
+static void *generic_copy_inplace_data(struct z_erofs_decompress_req *rq,
-			void *inpage, unsigned int *inputmargin, int *maptype,
+				       u8 *src, unsigned int pageofs_in)
-			bool support_0padding)
 {
-	unsigned int nrpages_in, nrpages_out;
+	/*
-	unsigned int ofull, oend, inputsize, total, i, j;
+	 * if in-place decompression is ongoing, those decompressed
-	struct page **in;
+	 * pages should be copied in order to avoid being overlapped.
-	void *src, *tmp;
+	 */
+	struct page **in = rq->in;
+	u8 *const tmp = erofs_get_pcpubuf(1);
+	u8 *tmpp = tmp;
+	unsigned int inlen = rq->inputsize - pageofs_in;
+	unsigned int count = min_t(uint, inlen, PAGE_SIZE - pageofs_in);
 
-	inputsize = rq->inputsize;
+	while (tmpp < tmp + inlen) {
-	nrpages_in = PAGE_ALIGN(inputsize) >> PAGE_SHIFT;
-	oend = rq->pageofs_out + rq->outputsize;
-	ofull = PAGE_ALIGN(oend);
-	nrpages_out = ofull >> PAGE_SHIFT;
-
-	if (rq->inplace_io) {
-		if (rq->partial_decoding || !support_0padding ||
-		    ofull - oend < LZ4_DECOMPRESS_INPLACE_MARGIN(inputsize))
-			goto docopy;
-
-		for (i = 0; i < nrpages_in; ++i) {
-			DBG_BUGON(rq->in[i] == NULL);
-			for (j = 0; j < nrpages_out - nrpages_in + i; ++j)
-				if (rq->out[j] == rq->in[i])
-					goto docopy;
-		}
-	}
-
-	if (nrpages_in <= 1) {
-		*maptype = 0;
-		return inpage;
-	}
-	kunmap_atomic(inpage);
-	might_sleep();
-	src = erofs_vm_map_ram(rq->in, nrpages_in);
 		if (!src)
-		return ERR_PTR(-ENOMEM);
+			src = kmap_atomic(*in);
-	*maptype = 1;
+		memcpy(tmpp, src + pageofs_in, count);
-	return src;
+		kunmap_atomic(src);
-
+		src = NULL;
-docopy:
+		tmpp += count;
-	/* Or copy compressed data which can be overlapped to per-CPU buffer */
+		pageofs_in = 0;
-	in = rq->in;
+		count = PAGE_SIZE;
-	src = erofs_get_pcpubuf(nrpages_in);
-	if (!src) {
-		DBG_BUGON(1);
-		kunmap_atomic(inpage);
-		return ERR_PTR(-EFAULT);
-	}
-
-	tmp = src;
-	total = rq->inputsize;
-	while (total) {
-		unsigned int page_copycnt =
-			min_t(unsigned int, total, PAGE_SIZE - *inputmargin);
-
-		if (!inpage)
-			inpage = kmap_atomic(*in);
-		memcpy(tmp, inpage + *inputmargin, page_copycnt);
-		kunmap_atomic(inpage);
-		inpage = NULL;
-		tmp += page_copycnt;
-		total -= page_copycnt;
 		++in;
-		*inputmargin = 0;
 	}
-	*maptype = 2;
+	return tmp;
-	return src;
 }
 
 static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 {
-	unsigned int inputmargin;
+	unsigned int inputmargin, inlen;
-	u8 *headpage, *src;
+	u8 *src;
-	bool support_0padding;
+	bool copied, support_0padding;
-	int ret, maptype;
+	int ret;
 
-	DBG_BUGON(*rq->in == NULL);
+	if (rq->inputsize > PAGE_SIZE)
-	headpage = kmap_atomic(*rq->in);
+		return -EOPNOTSUPP;
+
+	src = kmap_atomic(*rq->in);
 	inputmargin = 0;
 	support_0padding = false;
 
@@ -209,36 +168,49 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 	if (erofs_sb_has_lz4_0padding(EROFS_SB(rq->sb))) {
 		support_0padding = true;
 
-		while (!headpage[inputmargin & ~PAGE_MASK])
+		while (!src[inputmargin & ~PAGE_MASK])
 			if (!(++inputmargin & ~PAGE_MASK))
 				break;
 
 		if (inputmargin >= rq->inputsize) {
-			kunmap_atomic(headpage);
+			kunmap_atomic(src);
 			return -EIO;
 		}
 	}
 
-	rq->inputsize -= inputmargin;
+	copied = false;
-	src = z_erofs_handle_inplace_io(rq, headpage, &inputmargin, &maptype,
+	inlen = rq->inputsize - inputmargin;
-					support_0padding);
+	if (rq->inplace_io) {
-	if (IS_ERR(src))
+		const uint oend = (rq->pageofs_out +
-		return PTR_ERR(src);
+				   rq->outputsize) & ~PAGE_MASK;
+		const uint nr = PAGE_ALIGN(rq->pageofs_out +
+					   rq->outputsize) >> PAGE_SHIFT;
+
+		if (rq->partial_decoding || !support_0padding ||
+		    rq->out[nr - 1] != rq->in[0] ||
+		    rq->inputsize - oend <
+		      LZ4_DECOMPRESS_INPLACE_MARGIN(inlen)) {
+			src = generic_copy_inplace_data(rq, src, inputmargin);
+			inputmargin = 0;
+			copied = true;
+		}
+	}
 
 	/* legacy format could compress extra data in a pcluster. */
 	if (rq->partial_decoding || !support_0padding)
 		ret = LZ4_decompress_safe_partial(src + inputmargin, out,
-				rq->inputsize, rq->outputsize, rq->outputsize);
+						  inlen, rq->outputsize,
+						  rq->outputsize);
 	else
 		ret = LZ4_decompress_safe(src + inputmargin, out,
-					  rq->inputsize, rq->outputsize);
+					  inlen, rq->outputsize);
 
 	if (ret != rq->outputsize) {
 		erofs_err(rq->sb, "failed to decompress %d in[%u, %u] out[%u]",
-			  ret, rq->inputsize, inputmargin, rq->outputsize);
+			  ret, inlen, inputmargin, rq->outputsize);
 
 		print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET,
-			       16, 1, src + inputmargin, rq->inputsize, true);
+			       16, 1, src + inputmargin, inlen, true);
 		print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET,
 			       16, 1, out, rq->outputsize, true);
 
@@ -247,16 +219,10 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 		ret = -EIO;
 	}
 
-	if (maptype == 0) {
+	if (copied)
-		kunmap_atomic(src);
-	} else if (maptype == 1) {
-		vm_unmap_ram(src, PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT);
-	} else if (maptype == 2) {
 		erofs_put_pcpubuf(src);
-	} else {
+	else
-		DBG_BUGON(1);
+		kunmap_atomic(src);
-		return -EFAULT;
-	}
 	return ret;
 }
 
@@ -306,10 +272,8 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
 	const struct z_erofs_decompressor *alg = decompressors + rq->alg;
 	unsigned int dst_maptype;
 	void *dst;
-	int ret;
+	int ret, i;
 
-	/* 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);
@@ -336,21 +300,29 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
 		erofs_put_pcpubuf(dst);
 		return ret;
 	}
-	}
 
-	/* general decoding path which can be used for all cases */
 	ret = alg->prepare_destpages(rq, pagepool);
-	if (ret < 0)
+	if (ret < 0) {
 		return ret;
-	if (ret) {
+	} else if (ret) {
 		dst = page_address(*rq->out);
 		dst_maptype = 1;
 		goto dstmap_out;
 	}
 
-	dst = erofs_vm_map_ram(rq->out, nrpages_out);
+	i = 0;
+	while (1) {
+		dst = vm_map_ram(rq->out, nrpages_out, -1, PAGE_KERNEL);
+
+		/* retry two more times (totally 3 times) */
+		if (dst || ++i >= 3)
+			break;
+		vm_unmap_aliases();
+	}
+
 	if (!dst)
 		return -ENOMEM;
+
 	dst_maptype = 2;
 
 dstmap_out:

fs/erofs/internal.h

@@ -396,21 +396,6 @@ int erofs_namei(struct inode *dir, struct qstr *name,
 /* dir.c */
 extern const struct file_operations erofs_dir_fops;
 
-static inline void *erofs_vm_map_ram(struct page **pages, unsigned int count)
-{
-	int retried = 0;
-
-	while (1) {
-		void *p = vm_map_ram(pages, count, -1, PAGE_KERNEL);
-
-		/* retry two more times (totally 3 times) */
-		if (p || ++retried >= 3)
-			return p;
-		vm_unmap_aliases();
-	}
-	return NULL;
-}
-
 /* pcpubuf.c */
 void *erofs_get_pcpubuf(unsigned int requiredpages);
 void erofs_put_pcpubuf(void *ptr);