[PATCH] erofs: simplify compression configuration parser

[PATCH] erofs: simplify compression configuration parser

[Gao Xiang]

Move erofs_load_compr_cfgs() into decompressor.c as well as introduce
a callback instead of a hard-coded switch for each algorithm for
simplicity.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
 fs/erofs/compress.h             |  6 +++
 fs/erofs/decompressor.c         | 60 ++++++++++++++++++++++++++-
 fs/erofs/decompressor_deflate.c |  5 ++-
 fs/erofs/decompressor_lzma.c    |  4 +-
 fs/erofs/internal.h             | 38 +----------------
 fs/erofs/super.c                | 72 ++++-----------------------------
 6 files changed, 78 insertions(+), 107 deletions(-)

diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
index 349c3316ae6b..279933e007d2 100644
--- a/fs/erofs/compress.h
+++ b/fs/erofs/compress.h
@@ -21,6 +21,8 @@ struct z_erofs_decompress_req {
 };
 
 struct z_erofs_decompressor {
+	int (*config)(struct super_block *sb, struct erofs_super_block *dsb,
+		      void *data, int size);
 	int (*decompress)(struct z_erofs_decompress_req *rq,
 			  struct page **pagepool);
 	char *name;
@@ -92,6 +94,10 @@ int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
 extern const struct z_erofs_decompressor erofs_decompressors[];
 
 /* prototypes for specific algorithms */
+int z_erofs_load_lzma_config(struct super_block *sb,
+			struct erofs_super_block *dsb, void *data, int size);
+int z_erofs_load_deflate_config(struct super_block *sb,
+			struct erofs_super_block *dsb, void *data, int size);
 int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
 			    struct page **pagepool);
 int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 332ec5f74002..6cb57e45c180 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -25,10 +25,10 @@ struct z_erofs_lz4_decompress_ctx {
 };
 
 int z_erofs_load_lz4_config(struct super_block *sb,
-			    struct erofs_super_block *dsb,
-			    struct z_erofs_lz4_cfgs *lz4, int size)
+			    struct erofs_super_block *dsb, void *data, int size)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct z_erofs_lz4_cfgs *lz4 = data;
 	u16 distance;
 
 	if (lz4) {
@@ -370,19 +370,75 @@ const struct z_erofs_decompressor erofs_decompressors[] = {
 		.name = "interlaced"
 	},
 	[Z_EROFS_COMPRESSION_LZ4] = {
+		.config = z_erofs_load_lz4_config,
 		.decompress = z_erofs_lz4_decompress,
 		.name = "lz4"
 	},
 #ifdef CONFIG_EROFS_FS_ZIP_LZMA
 	[Z_EROFS_COMPRESSION_LZMA] = {
+		.config = z_erofs_load_lzma_config,
 		.decompress = z_erofs_lzma_decompress,
 		.name = "lzma"
 	},
 #endif
 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
 	[Z_EROFS_COMPRESSION_DEFLATE] = {
+		.config = z_erofs_load_deflate_config,
 		.decompress = z_erofs_deflate_decompress,
 		.name = "deflate"
 	},
 #endif
 };
+
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+	unsigned int algs, alg;
+	erofs_off_t offset;
+	int size, ret = 0;
+
+	if (!erofs_sb_has_compr_cfgs(sbi)) {
+		sbi->available_compr_algs = Z_EROFS_COMPRESSION_LZ4;
+		return z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	}
+
+	sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
+	if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
+		erofs_err(sb, "unidentified algorithms %x, please upgrade kernel",
+			  sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
+		return -EOPNOTSUPP;
+	}
+
+	erofs_init_metabuf(&buf, sb);
+	offset = EROFS_SUPER_OFFSET + sbi->sb_size;
+	alg = 0;
+	for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
+		void *data;
+
+		if (!(algs & 1))
+			continue;
+
+		data = erofs_read_metadata(sb, &buf, &offset, &size);
+		if (IS_ERR(data)) {
+			ret = PTR_ERR(data);
+			break;
+		}
+
+		if (alg >= ARRAY_SIZE(erofs_decompressors) ||
+		    !erofs_decompressors[alg].config) {
+			erofs_err(sb, "algorithm %d isn't enabled on this kernel",
+				  alg);
+			ret = -EOPNOTSUPP;
+		} else {
+			ret = erofs_decompressors[alg].config(sb,
+					dsb, data, size);
+		}
+
+		kfree(data);
+		if (ret)
+			break;
+	}
+	erofs_put_metabuf(&buf);
+	return ret;
+}
diff --git a/fs/erofs/decompressor_deflate.c b/fs/erofs/decompressor_deflate.c
index 19e5bdeb30b6..0e1946a6bda5 100644
--- a/fs/erofs/decompressor_deflate.c
+++ b/fs/erofs/decompressor_deflate.c
@@ -77,9 +77,10 @@ int __init z_erofs_deflate_init(void)
 }
 
 int z_erofs_load_deflate_config(struct super_block *sb,
-				struct erofs_super_block *dsb,
-				struct z_erofs_deflate_cfgs *dfl, int size)
+			struct erofs_super_block *dsb, void *data, int size)
 {
+	struct z_erofs_deflate_cfgs *dfl = data;
+
 	if (!dfl || size < sizeof(struct z_erofs_deflate_cfgs)) {
 		erofs_err(sb, "invalid deflate cfgs, size=%u", size);
 		return -EINVAL;
diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
index dee10d22ada9..ba4ec73f4aae 100644
--- a/fs/erofs/decompressor_lzma.c
+++ b/fs/erofs/decompressor_lzma.c
@@ -72,10 +72,10 @@ int __init z_erofs_lzma_init(void)
 }
 
 int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size)
+			struct erofs_super_block *dsb, void *data, int size)
 {
 	static DEFINE_MUTEX(lzma_resize_mutex);
+	struct z_erofs_lzma_cfgs *lzma = data;
 	unsigned int dict_size, i;
 	struct z_erofs_lzma *strm, *head = NULL;
 	int err;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 4ff88d0dd980..d8de61350dc0 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -469,9 +469,6 @@ int __init z_erofs_init_zip_subsystem(void);
 void z_erofs_exit_zip_subsystem(void);
 int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
 				       struct erofs_workgroup *egrp);
-int z_erofs_load_lz4_config(struct super_block *sb,
-			    struct erofs_super_block *dsb,
-			    struct z_erofs_lz4_cfgs *lz4, int len);
 int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
 			    int flags);
 void *erofs_get_pcpubuf(unsigned int requiredpages);
@@ -480,6 +477,7 @@ int erofs_pcpubuf_growsize(unsigned int nrpages);
 void __init erofs_pcpubuf_init(void);
 void erofs_pcpubuf_exit(void);
 int erofs_init_managed_cache(struct super_block *sb);
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb);
 #else
 static inline void erofs_shrinker_register(struct super_block *sb) {}
 static inline void erofs_shrinker_unregister(struct super_block *sb) {}
@@ -487,16 +485,6 @@ static inline int erofs_init_shrinker(void) { return 0; }
 static inline void erofs_exit_shrinker(void) {}
 static inline int z_erofs_init_zip_subsystem(void) { return 0; }
 static inline void z_erofs_exit_zip_subsystem(void) {}
-static inline int z_erofs_load_lz4_config(struct super_block *sb,
-				  struct erofs_super_block *dsb,
-				  struct z_erofs_lz4_cfgs *lz4, int len)
-{
-	if (lz4 || dsb->u1.lz4_max_distance) {
-		erofs_err(sb, "lz4 algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 static inline void erofs_pcpubuf_init(void) {}
 static inline void erofs_pcpubuf_exit(void) {}
 static inline int erofs_init_managed_cache(struct super_block *sb) { return 0; }
@@ -505,41 +493,17 @@ static inline int erofs_init_managed_cache(struct super_block *sb) { return 0; }
 #ifdef CONFIG_EROFS_FS_ZIP_LZMA
 int __init z_erofs_lzma_init(void);
 void z_erofs_lzma_exit(void);
-int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size);
 #else
 static inline int z_erofs_lzma_init(void) { return 0; }
 static inline int z_erofs_lzma_exit(void) { return 0; }
-static inline int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size) {
-	if (lzma) {
-		erofs_err(sb, "lzma algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 #endif	/* !CONFIG_EROFS_FS_ZIP_LZMA */
 
 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
 int __init z_erofs_deflate_init(void);
 void z_erofs_deflate_exit(void);
-int z_erofs_load_deflate_config(struct super_block *sb,
-				struct erofs_super_block *dsb,
-				struct z_erofs_deflate_cfgs *dfl, int size);
 #else
 static inline int z_erofs_deflate_init(void) { return 0; }
 static inline int z_erofs_deflate_exit(void) { return 0; }
-static inline int z_erofs_load_deflate_config(struct super_block *sb,
-			struct erofs_super_block *dsb,
-			struct z_erofs_deflate_cfgs *dfl, int size) {
-	if (dfl) {
-		erofs_err(sb, "deflate algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 #endif	/* !CONFIG_EROFS_FS_ZIP_DEFLATE */
 
 #ifdef CONFIG_EROFS_FS_ONDEMAND
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 3700af9ee173..cc44fb2e001e 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -156,68 +156,15 @@ void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
 	return buffer;
 }
 
-#ifdef CONFIG_EROFS_FS_ZIP
-static int erofs_load_compr_cfgs(struct super_block *sb,
-				 struct erofs_super_block *dsb)
+#ifndef CONFIG_EROFS_FS_ZIP
+static int z_erofs_parse_cfgs(struct super_block *sb,
+			      struct erofs_super_block *dsb)
 {
-	struct erofs_sb_info *sbi = EROFS_SB(sb);
-	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
-	unsigned int algs, alg;
-	erofs_off_t offset;
-	int size, ret = 0;
-
-	sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
-	if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
-		erofs_err(sb, "try to load compressed fs with unsupported algorithms %x",
-			  sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
-		return -EINVAL;
-	}
-
-	erofs_init_metabuf(&buf, sb);
-	offset = EROFS_SUPER_OFFSET + sbi->sb_size;
-	alg = 0;
-	for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
-		void *data;
-
-		if (!(algs & 1))
-			continue;
-
-		data = erofs_read_metadata(sb, &buf, &offset, &size);
-		if (IS_ERR(data)) {
-			ret = PTR_ERR(data);
-			break;
-		}
+	if (!dsb->u1.available_compr_algs)
+		return 0;
 
-		switch (alg) {
-		case Z_EROFS_COMPRESSION_LZ4:
-			ret = z_erofs_load_lz4_config(sb, dsb, data, size);
-			break;
-		case Z_EROFS_COMPRESSION_LZMA:
-			ret = z_erofs_load_lzma_config(sb, dsb, data, size);
-			break;
-		case Z_EROFS_COMPRESSION_DEFLATE:
-			ret = z_erofs_load_deflate_config(sb, dsb, data, size);
-			break;
-		default:
-			DBG_BUGON(1);
-			ret = -EFAULT;
-		}
-		kfree(data);
-		if (ret)
-			break;
-	}
-	erofs_put_metabuf(&buf);
-	return ret;
-}
-#else
-static int erofs_load_compr_cfgs(struct super_block *sb,
-				 struct erofs_super_block *dsb)
-{
-	if (dsb->u1.available_compr_algs) {
-		erofs_err(sb, "try to load compressed fs when compression is disabled");
-		return -EINVAL;
-	}
-	return 0;
+	erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
+	return -EOPNOTSUPP;
 }
 #endif
 
@@ -406,10 +353,7 @@ static int erofs_read_superblock(struct super_block *sb)
 	}
 
 	/* parse on-disk compression configurations */
-	if (erofs_sb_has_compr_cfgs(sbi))
-		ret = erofs_load_compr_cfgs(sb, dsb);
-	else
-		ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	ret = z_erofs_parse_cfgs(sb, dsb);
 	if (ret < 0)
 		goto out;
 
-- 
2.39.3

[PATCH] erofs: simplify compression configuration parser

[Gao Xiang]

Move erofs_load_compr_cfgs() into decompressor.c as well as introduce
a callback instead of a hard-coded switch for each algorithm for
simplicity.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
 fs/erofs/compress.h             |  6 +++
 fs/erofs/decompressor.c         | 60 ++++++++++++++++++++++++++-
 fs/erofs/decompressor_deflate.c |  5 ++-
 fs/erofs/decompressor_lzma.c    |  4 +-
 fs/erofs/internal.h             | 38 +----------------
 fs/erofs/super.c                | 72 ++++-----------------------------
 6 files changed, 78 insertions(+), 107 deletions(-)

diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
index 349c3316ae6b..279933e007d2 100644
--- a/fs/erofs/compress.h
+++ b/fs/erofs/compress.h
@@ -21,6 +21,8 @@ struct z_erofs_decompress_req {
 };
 
 struct z_erofs_decompressor {
+	int (*config)(struct super_block *sb, struct erofs_super_block *dsb,
+		      void *data, int size);
 	int (*decompress)(struct z_erofs_decompress_req *rq,
 			  struct page **pagepool);
 	char *name;
@@ -92,6 +94,10 @@ int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
 extern const struct z_erofs_decompressor erofs_decompressors[];
 
 /* prototypes for specific algorithms */
+int z_erofs_load_lzma_config(struct super_block *sb,
+			struct erofs_super_block *dsb, void *data, int size);
+int z_erofs_load_deflate_config(struct super_block *sb,
+			struct erofs_super_block *dsb, void *data, int size);
 int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
 			    struct page **pagepool);
 int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 332ec5f74002..6cb57e45c180 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -25,10 +25,10 @@ struct z_erofs_lz4_decompress_ctx {
 };
 
 int z_erofs_load_lz4_config(struct super_block *sb,
-			    struct erofs_super_block *dsb,
-			    struct z_erofs_lz4_cfgs *lz4, int size)
+			    struct erofs_super_block *dsb, void *data, int size)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct z_erofs_lz4_cfgs *lz4 = data;
 	u16 distance;
 
 	if (lz4) {
@@ -370,19 +370,75 @@ const struct z_erofs_decompressor erofs_decompressors[] = {
 		.name = "interlaced"
 	},
 	[Z_EROFS_COMPRESSION_LZ4] = {
+		.config = z_erofs_load_lz4_config,
 		.decompress = z_erofs_lz4_decompress,
 		.name = "lz4"
 	},
 #ifdef CONFIG_EROFS_FS_ZIP_LZMA
 	[Z_EROFS_COMPRESSION_LZMA] = {
+		.config = z_erofs_load_lzma_config,
 		.decompress = z_erofs_lzma_decompress,
 		.name = "lzma"
 	},
 #endif
 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
 	[Z_EROFS_COMPRESSION_DEFLATE] = {
+		.config = z_erofs_load_deflate_config,
 		.decompress = z_erofs_deflate_decompress,
 		.name = "deflate"
 	},
 #endif
 };
+
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+	unsigned int algs, alg;
+	erofs_off_t offset;
+	int size, ret = 0;
+
+	if (!erofs_sb_has_compr_cfgs(sbi)) {
+		sbi->available_compr_algs = Z_EROFS_COMPRESSION_LZ4;
+		return z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	}
+
+	sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
+	if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
+		erofs_err(sb, "unidentified algorithms %x, please upgrade kernel",
+			  sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
+		return -EOPNOTSUPP;
+	}
+
+	erofs_init_metabuf(&buf, sb);
+	offset = EROFS_SUPER_OFFSET + sbi->sb_size;
+	alg = 0;
+	for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
+		void *data;
+
+		if (!(algs & 1))
+			continue;
+
+		data = erofs_read_metadata(sb, &buf, &offset, &size);
+		if (IS_ERR(data)) {
+			ret = PTR_ERR(data);
+			break;
+		}
+
+		if (alg >= ARRAY_SIZE(erofs_decompressors) ||
+		    !erofs_decompressors[alg].config) {
+			erofs_err(sb, "algorithm %d isn't enabled on this kernel",
+				  alg);
+			ret = -EOPNOTSUPP;
+		} else {
+			ret = erofs_decompressors[alg].config(sb,
+					dsb, data, size);
+		}
+
+		kfree(data);
+		if (ret)
+			break;
+	}
+	erofs_put_metabuf(&buf);
+	return ret;
+}
diff --git a/fs/erofs/decompressor_deflate.c b/fs/erofs/decompressor_deflate.c
index 19e5bdeb30b6..0e1946a6bda5 100644
--- a/fs/erofs/decompressor_deflate.c
+++ b/fs/erofs/decompressor_deflate.c
@@ -77,9 +77,10 @@ int __init z_erofs_deflate_init(void)
 }
 
 int z_erofs_load_deflate_config(struct super_block *sb,
-				struct erofs_super_block *dsb,
-				struct z_erofs_deflate_cfgs *dfl, int size)
+			struct erofs_super_block *dsb, void *data, int size)
 {
+	struct z_erofs_deflate_cfgs *dfl = data;
+
 	if (!dfl || size < sizeof(struct z_erofs_deflate_cfgs)) {
 		erofs_err(sb, "invalid deflate cfgs, size=%u", size);
 		return -EINVAL;
diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
index dee10d22ada9..ba4ec73f4aae 100644
--- a/fs/erofs/decompressor_lzma.c
+++ b/fs/erofs/decompressor_lzma.c
@@ -72,10 +72,10 @@ int __init z_erofs_lzma_init(void)
 }
 
 int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size)
+			struct erofs_super_block *dsb, void *data, int size)
 {
 	static DEFINE_MUTEX(lzma_resize_mutex);
+	struct z_erofs_lzma_cfgs *lzma = data;
 	unsigned int dict_size, i;
 	struct z_erofs_lzma *strm, *head = NULL;
 	int err;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 4ff88d0dd980..d8de61350dc0 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -469,9 +469,6 @@ int __init z_erofs_init_zip_subsystem(void);
 void z_erofs_exit_zip_subsystem(void);
 int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
 				       struct erofs_workgroup *egrp);
-int z_erofs_load_lz4_config(struct super_block *sb,
-			    struct erofs_super_block *dsb,
-			    struct z_erofs_lz4_cfgs *lz4, int len);
 int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
 			    int flags);
 void *erofs_get_pcpubuf(unsigned int requiredpages);
@@ -480,6 +477,7 @@ int erofs_pcpubuf_growsize(unsigned int nrpages);
 void __init erofs_pcpubuf_init(void);
 void erofs_pcpubuf_exit(void);
 int erofs_init_managed_cache(struct super_block *sb);
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb);
 #else
 static inline void erofs_shrinker_register(struct super_block *sb) {}
 static inline void erofs_shrinker_unregister(struct super_block *sb) {}
@@ -487,16 +485,6 @@ static inline int erofs_init_shrinker(void) { return 0; }
 static inline void erofs_exit_shrinker(void) {}
 static inline int z_erofs_init_zip_subsystem(void) { return 0; }
 static inline void z_erofs_exit_zip_subsystem(void) {}
-static inline int z_erofs_load_lz4_config(struct super_block *sb,
-				  struct erofs_super_block *dsb,
-				  struct z_erofs_lz4_cfgs *lz4, int len)
-{
-	if (lz4 || dsb->u1.lz4_max_distance) {
-		erofs_err(sb, "lz4 algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 static inline void erofs_pcpubuf_init(void) {}
 static inline void erofs_pcpubuf_exit(void) {}
 static inline int erofs_init_managed_cache(struct super_block *sb) { return 0; }
@@ -505,41 +493,17 @@ static inline int erofs_init_managed_cache(struct super_block *sb) { return 0; }
 #ifdef CONFIG_EROFS_FS_ZIP_LZMA
 int __init z_erofs_lzma_init(void);
 void z_erofs_lzma_exit(void);
-int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size);
 #else
 static inline int z_erofs_lzma_init(void) { return 0; }
 static inline int z_erofs_lzma_exit(void) { return 0; }
-static inline int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size) {
-	if (lzma) {
-		erofs_err(sb, "lzma algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 #endif	/* !CONFIG_EROFS_FS_ZIP_LZMA */
 
 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
 int __init z_erofs_deflate_init(void);
 void z_erofs_deflate_exit(void);
-int z_erofs_load_deflate_config(struct super_block *sb,
-				struct erofs_super_block *dsb,
-				struct z_erofs_deflate_cfgs *dfl, int size);
 #else
 static inline int z_erofs_deflate_init(void) { return 0; }
 static inline int z_erofs_deflate_exit(void) { return 0; }
-static inline int z_erofs_load_deflate_config(struct super_block *sb,
-			struct erofs_super_block *dsb,
-			struct z_erofs_deflate_cfgs *dfl, int size) {
-	if (dfl) {
-		erofs_err(sb, "deflate algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 #endif	/* !CONFIG_EROFS_FS_ZIP_DEFLATE */
 
 #ifdef CONFIG_EROFS_FS_ONDEMAND
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 3700af9ee173..cc44fb2e001e 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -156,68 +156,15 @@ void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
 	return buffer;
 }
 
-#ifdef CONFIG_EROFS_FS_ZIP
-static int erofs_load_compr_cfgs(struct super_block *sb,
-				 struct erofs_super_block *dsb)
+#ifndef CONFIG_EROFS_FS_ZIP
+static int z_erofs_parse_cfgs(struct super_block *sb,
+			      struct erofs_super_block *dsb)
 {
-	struct erofs_sb_info *sbi = EROFS_SB(sb);
-	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
-	unsigned int algs, alg;
-	erofs_off_t offset;
-	int size, ret = 0;
-
-	sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
-	if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
-		erofs_err(sb, "try to load compressed fs with unsupported algorithms %x",
-			  sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
-		return -EINVAL;
-	}
-
-	erofs_init_metabuf(&buf, sb);
-	offset = EROFS_SUPER_OFFSET + sbi->sb_size;
-	alg = 0;
-	for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
-		void *data;
-
-		if (!(algs & 1))
-			continue;
-
-		data = erofs_read_metadata(sb, &buf, &offset, &size);
-		if (IS_ERR(data)) {
-			ret = PTR_ERR(data);
-			break;
-		}
+	if (!dsb->u1.available_compr_algs)
+		return 0;
 
-		switch (alg) {
-		case Z_EROFS_COMPRESSION_LZ4:
-			ret = z_erofs_load_lz4_config(sb, dsb, data, size);
-			break;
-		case Z_EROFS_COMPRESSION_LZMA:
-			ret = z_erofs_load_lzma_config(sb, dsb, data, size);
-			break;
-		case Z_EROFS_COMPRESSION_DEFLATE:
-			ret = z_erofs_load_deflate_config(sb, dsb, data, size);
-			break;
-		default:
-			DBG_BUGON(1);
-			ret = -EFAULT;
-		}
-		kfree(data);
-		if (ret)
-			break;
-	}
-	erofs_put_metabuf(&buf);
-	return ret;
-}
-#else
-static int erofs_load_compr_cfgs(struct super_block *sb,
-				 struct erofs_super_block *dsb)
-{
-	if (dsb->u1.available_compr_algs) {
-		erofs_err(sb, "try to load compressed fs when compression is disabled");
-		return -EINVAL;
-	}
-	return 0;
+	erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
+	return -EOPNOTSUPP;
 }
 #endif
 
@@ -406,10 +353,7 @@ static int erofs_read_superblock(struct super_block *sb)
 	}
 
 	/* parse on-disk compression configurations */
-	if (erofs_sb_has_compr_cfgs(sbi))
-		ret = erofs_load_compr_cfgs(sb, dsb);
-	else
-		ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	ret = z_erofs_parse_cfgs(sb, dsb);
 	if (ret < 0)
 		goto out;
 
-- 
2.39.3

Re: [PATCH] erofs: simplify compression configuration parser

[kernel test robot]

Hi Gao,

kernel test robot noticed the following build warnings:

[auto build test WARNING on xiang-erofs/dev-test]
[also build test WARNING on xiang-erofs/dev xiang-erofs/fixes linus/master v6.6-rc6 next-20231020]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Gao-Xiang/erofs-simplify-compression-configuration-parser/20231021-100253
base:   https://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git dev-test
patch link:    https://lore.kernel.org/r/20231021020109.1646299-1-hsiangkao%40linux.alibaba.com
patch subject: [PATCH] erofs: simplify compression configuration parser
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20231021/202310211151.sklVyQL9-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231021/202310211151.sklVyQL9-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310211151.sklVyQL9-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> fs/erofs/decompressor.c:27:5: warning: no previous prototype for 'z_erofs_load_lz4_config' [-Wmissing-prototypes]
      27 | int z_erofs_load_lz4_config(struct super_block *sb,
         |     ^~~~~~~~~~~~~~~~~~~~~~~


vim +/z_erofs_load_lz4_config +27 fs/erofs/decompressor.c

d67aee76d41861 Gao Xiang    2021-12-28  26  
5d50538fc567c6 Huang Jianan 2021-03-29 @27  int z_erofs_load_lz4_config(struct super_block *sb,
51fd9879fa6135 Gao Xiang    2023-10-21  28  			    struct erofs_super_block *dsb, void *data, int size)
5d50538fc567c6 Huang Jianan 2021-03-29  29  {
4fea63f7d76e42 Gao Xiang    2021-04-07  30  	struct erofs_sb_info *sbi = EROFS_SB(sb);
51fd9879fa6135 Gao Xiang    2023-10-21  31  	struct z_erofs_lz4_cfgs *lz4 = data;
46249cded18ac0 Gao Xiang    2021-03-29  32  	u16 distance;
46249cded18ac0 Gao Xiang    2021-03-29  33  
46249cded18ac0 Gao Xiang    2021-03-29  34  	if (lz4) {
46249cded18ac0 Gao Xiang    2021-03-29  35  		if (size < sizeof(struct z_erofs_lz4_cfgs)) {
46249cded18ac0 Gao Xiang    2021-03-29  36  			erofs_err(sb, "invalid lz4 cfgs, size=%u", size);
46249cded18ac0 Gao Xiang    2021-03-29  37  			return -EINVAL;
46249cded18ac0 Gao Xiang    2021-03-29  38  		}
46249cded18ac0 Gao Xiang    2021-03-29  39  		distance = le16_to_cpu(lz4->max_distance);
4fea63f7d76e42 Gao Xiang    2021-04-07  40  
4fea63f7d76e42 Gao Xiang    2021-04-07  41  		sbi->lz4.max_pclusterblks = le16_to_cpu(lz4->max_pclusterblks);
4fea63f7d76e42 Gao Xiang    2021-04-07  42  		if (!sbi->lz4.max_pclusterblks) {
4fea63f7d76e42 Gao Xiang    2021-04-07  43  			sbi->lz4.max_pclusterblks = 1;	/* reserved case */
4fea63f7d76e42 Gao Xiang    2021-04-07  44  		} else if (sbi->lz4.max_pclusterblks >
3acea5fc335420 Jingbo Xu    2023-03-13  45  			   erofs_blknr(sb, Z_EROFS_PCLUSTER_MAX_SIZE)) {
4fea63f7d76e42 Gao Xiang    2021-04-07  46  			erofs_err(sb, "too large lz4 pclusterblks %u",
4fea63f7d76e42 Gao Xiang    2021-04-07  47  				  sbi->lz4.max_pclusterblks);
4fea63f7d76e42 Gao Xiang    2021-04-07  48  			return -EINVAL;
4fea63f7d76e42 Gao Xiang    2021-04-07  49  		}
46249cded18ac0 Gao Xiang    2021-03-29  50  	} else {
14373711dd54be Gao Xiang    2021-03-29  51  		distance = le16_to_cpu(dsb->u1.lz4_max_distance);
4fea63f7d76e42 Gao Xiang    2021-04-07  52  		sbi->lz4.max_pclusterblks = 1;
46249cded18ac0 Gao Xiang    2021-03-29  53  	}
5d50538fc567c6 Huang Jianan 2021-03-29  54  
4fea63f7d76e42 Gao Xiang    2021-04-07  55  	sbi->lz4.max_distance_pages = distance ?
5d50538fc567c6 Huang Jianan 2021-03-29  56  					DIV_ROUND_UP(distance, PAGE_SIZE) + 1 :
5d50538fc567c6 Huang Jianan 2021-03-29  57  					LZ4_MAX_DISTANCE_PAGES;
4fea63f7d76e42 Gao Xiang    2021-04-07  58  	return erofs_pcpubuf_growsize(sbi->lz4.max_pclusterblks);
5d50538fc567c6 Huang Jianan 2021-03-29  59  }
5d50538fc567c6 Huang Jianan 2021-03-29  60  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH v2] erofs: simplify compression configuration parser

[Gao Xiang]

From: Gao Xiang <hsiangkao@linux.alibaba.com>

Move erofs_load_compr_cfgs() into decompressor.c as well as introduce
a callback instead of a hard-coded switch for each algorithm for
simplicity.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
v2:
 - fix build warning of `-Wmissing-declarations`
   https://lore.kernel.org/r/202310221347.8YPc9FUC-lkp@intel.com

 fs/erofs/compress.h             |  6 +++
 fs/erofs/decompressor.c         | 62 ++++++++++++++++++++++++++--
 fs/erofs/decompressor_deflate.c |  5 ++-
 fs/erofs/decompressor_lzma.c    |  4 +-
 fs/erofs/internal.h             | 38 +----------------
 fs/erofs/super.c                | 72 ++++-----------------------------
 6 files changed, 79 insertions(+), 108 deletions(-)

diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
index 349c3316ae6b..279933e007d2 100644
--- a/fs/erofs/compress.h
+++ b/fs/erofs/compress.h
@@ -21,6 +21,8 @@ struct z_erofs_decompress_req {
 };
 
 struct z_erofs_decompressor {
+	int (*config)(struct super_block *sb, struct erofs_super_block *dsb,
+		      void *data, int size);
 	int (*decompress)(struct z_erofs_decompress_req *rq,
 			  struct page **pagepool);
 	char *name;
@@ -92,6 +94,10 @@ int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
 extern const struct z_erofs_decompressor erofs_decompressors[];
 
 /* prototypes for specific algorithms */
+int z_erofs_load_lzma_config(struct super_block *sb,
+			struct erofs_super_block *dsb, void *data, int size);
+int z_erofs_load_deflate_config(struct super_block *sb,
+			struct erofs_super_block *dsb, void *data, int size);
 int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
 			    struct page **pagepool);
 int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 332ec5f74002..e75edc8f1753 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -24,11 +24,11 @@ struct z_erofs_lz4_decompress_ctx {
 	unsigned int oend;
 };
 
-int z_erofs_load_lz4_config(struct super_block *sb,
-			    struct erofs_super_block *dsb,
-			    struct z_erofs_lz4_cfgs *lz4, int size)
+static int z_erofs_load_lz4_config(struct super_block *sb,
+			    struct erofs_super_block *dsb, void *data, int size)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct z_erofs_lz4_cfgs *lz4 = data;
 	u16 distance;
 
 	if (lz4) {
@@ -370,19 +370,75 @@ const struct z_erofs_decompressor erofs_decompressors[] = {
 		.name = "interlaced"
 	},
 	[Z_EROFS_COMPRESSION_LZ4] = {
+		.config = z_erofs_load_lz4_config,
 		.decompress = z_erofs_lz4_decompress,
 		.name = "lz4"
 	},
 #ifdef CONFIG_EROFS_FS_ZIP_LZMA
 	[Z_EROFS_COMPRESSION_LZMA] = {
+		.config = z_erofs_load_lzma_config,
 		.decompress = z_erofs_lzma_decompress,
 		.name = "lzma"
 	},
 #endif
 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
 	[Z_EROFS_COMPRESSION_DEFLATE] = {
+		.config = z_erofs_load_deflate_config,
 		.decompress = z_erofs_deflate_decompress,
 		.name = "deflate"
 	},
 #endif
 };
+
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+	unsigned int algs, alg;
+	erofs_off_t offset;
+	int size, ret = 0;
+
+	if (!erofs_sb_has_compr_cfgs(sbi)) {
+		sbi->available_compr_algs = Z_EROFS_COMPRESSION_LZ4;
+		return z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	}
+
+	sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
+	if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
+		erofs_err(sb, "unidentified algorithms %x, please upgrade kernel",
+			  sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
+		return -EOPNOTSUPP;
+	}
+
+	erofs_init_metabuf(&buf, sb);
+	offset = EROFS_SUPER_OFFSET + sbi->sb_size;
+	alg = 0;
+	for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
+		void *data;
+
+		if (!(algs & 1))
+			continue;
+
+		data = erofs_read_metadata(sb, &buf, &offset, &size);
+		if (IS_ERR(data)) {
+			ret = PTR_ERR(data);
+			break;
+		}
+
+		if (alg >= ARRAY_SIZE(erofs_decompressors) ||
+		    !erofs_decompressors[alg].config) {
+			erofs_err(sb, "algorithm %d isn't enabled on this kernel",
+				  alg);
+			ret = -EOPNOTSUPP;
+		} else {
+			ret = erofs_decompressors[alg].config(sb,
+					dsb, data, size);
+		}
+
+		kfree(data);
+		if (ret)
+			break;
+	}
+	erofs_put_metabuf(&buf);
+	return ret;
+}
diff --git a/fs/erofs/decompressor_deflate.c b/fs/erofs/decompressor_deflate.c
index 19e5bdeb30b6..0e1946a6bda5 100644
--- a/fs/erofs/decompressor_deflate.c
+++ b/fs/erofs/decompressor_deflate.c
@@ -77,9 +77,10 @@ int __init z_erofs_deflate_init(void)
 }
 
 int z_erofs_load_deflate_config(struct super_block *sb,
-				struct erofs_super_block *dsb,
-				struct z_erofs_deflate_cfgs *dfl, int size)
+			struct erofs_super_block *dsb, void *data, int size)
 {
+	struct z_erofs_deflate_cfgs *dfl = data;
+
 	if (!dfl || size < sizeof(struct z_erofs_deflate_cfgs)) {
 		erofs_err(sb, "invalid deflate cfgs, size=%u", size);
 		return -EINVAL;
diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
index 5f413f19a064..852dd8eac5df 100644
--- a/fs/erofs/decompressor_lzma.c
+++ b/fs/erofs/decompressor_lzma.c
@@ -72,10 +72,10 @@ int __init z_erofs_lzma_init(void)
 }
 
 int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size)
+			struct erofs_super_block *dsb, void *data, int size)
 {
 	static DEFINE_MUTEX(lzma_resize_mutex);
+	struct z_erofs_lzma_cfgs *lzma = data;
 	unsigned int dict_size, i;
 	struct z_erofs_lzma *strm, *head = NULL;
 	int err;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 4ff88d0dd980..d8de61350dc0 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -469,9 +469,6 @@ int __init z_erofs_init_zip_subsystem(void);
 void z_erofs_exit_zip_subsystem(void);
 int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
 				       struct erofs_workgroup *egrp);
-int z_erofs_load_lz4_config(struct super_block *sb,
-			    struct erofs_super_block *dsb,
-			    struct z_erofs_lz4_cfgs *lz4, int len);
 int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
 			    int flags);
 void *erofs_get_pcpubuf(unsigned int requiredpages);
@@ -480,6 +477,7 @@ int erofs_pcpubuf_growsize(unsigned int nrpages);
 void __init erofs_pcpubuf_init(void);
 void erofs_pcpubuf_exit(void);
 int erofs_init_managed_cache(struct super_block *sb);
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb);
 #else
 static inline void erofs_shrinker_register(struct super_block *sb) {}
 static inline void erofs_shrinker_unregister(struct super_block *sb) {}
@@ -487,16 +485,6 @@ static inline int erofs_init_shrinker(void) { return 0; }
 static inline void erofs_exit_shrinker(void) {}
 static inline int z_erofs_init_zip_subsystem(void) { return 0; }
 static inline void z_erofs_exit_zip_subsystem(void) {}
-static inline int z_erofs_load_lz4_config(struct super_block *sb,
-				  struct erofs_super_block *dsb,
-				  struct z_erofs_lz4_cfgs *lz4, int len)
-{
-	if (lz4 || dsb->u1.lz4_max_distance) {
-		erofs_err(sb, "lz4 algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 static inline void erofs_pcpubuf_init(void) {}
 static inline void erofs_pcpubuf_exit(void) {}
 static inline int erofs_init_managed_cache(struct super_block *sb) { return 0; }
@@ -505,41 +493,17 @@ static inline int erofs_init_managed_cache(struct super_block *sb) { return 0; }
 #ifdef CONFIG_EROFS_FS_ZIP_LZMA
 int __init z_erofs_lzma_init(void);
 void z_erofs_lzma_exit(void);
-int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size);
 #else
 static inline int z_erofs_lzma_init(void) { return 0; }
 static inline int z_erofs_lzma_exit(void) { return 0; }
-static inline int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size) {
-	if (lzma) {
-		erofs_err(sb, "lzma algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 #endif	/* !CONFIG_EROFS_FS_ZIP_LZMA */
 
 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
 int __init z_erofs_deflate_init(void);
 void z_erofs_deflate_exit(void);
-int z_erofs_load_deflate_config(struct super_block *sb,
-				struct erofs_super_block *dsb,
-				struct z_erofs_deflate_cfgs *dfl, int size);
 #else
 static inline int z_erofs_deflate_init(void) { return 0; }
 static inline int z_erofs_deflate_exit(void) { return 0; }
-static inline int z_erofs_load_deflate_config(struct super_block *sb,
-			struct erofs_super_block *dsb,
-			struct z_erofs_deflate_cfgs *dfl, int size) {
-	if (dfl) {
-		erofs_err(sb, "deflate algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 #endif	/* !CONFIG_EROFS_FS_ZIP_DEFLATE */
 
 #ifdef CONFIG_EROFS_FS_ONDEMAND
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 3700af9ee173..cc44fb2e001e 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -156,68 +156,15 @@ void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
 	return buffer;
 }
 
-#ifdef CONFIG_EROFS_FS_ZIP
-static int erofs_load_compr_cfgs(struct super_block *sb,
-				 struct erofs_super_block *dsb)
+#ifndef CONFIG_EROFS_FS_ZIP
+static int z_erofs_parse_cfgs(struct super_block *sb,
+			      struct erofs_super_block *dsb)
 {
-	struct erofs_sb_info *sbi = EROFS_SB(sb);
-	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
-	unsigned int algs, alg;
-	erofs_off_t offset;
-	int size, ret = 0;
-
-	sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
-	if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
-		erofs_err(sb, "try to load compressed fs with unsupported algorithms %x",
-			  sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
-		return -EINVAL;
-	}
-
-	erofs_init_metabuf(&buf, sb);
-	offset = EROFS_SUPER_OFFSET + sbi->sb_size;
-	alg = 0;
-	for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
-		void *data;
-
-		if (!(algs & 1))
-			continue;
-
-		data = erofs_read_metadata(sb, &buf, &offset, &size);
-		if (IS_ERR(data)) {
-			ret = PTR_ERR(data);
-			break;
-		}
+	if (!dsb->u1.available_compr_algs)
+		return 0;
 
-		switch (alg) {
-		case Z_EROFS_COMPRESSION_LZ4:
-			ret = z_erofs_load_lz4_config(sb, dsb, data, size);
-			break;
-		case Z_EROFS_COMPRESSION_LZMA:
-			ret = z_erofs_load_lzma_config(sb, dsb, data, size);
-			break;
-		case Z_EROFS_COMPRESSION_DEFLATE:
-			ret = z_erofs_load_deflate_config(sb, dsb, data, size);
-			break;
-		default:
-			DBG_BUGON(1);
-			ret = -EFAULT;
-		}
-		kfree(data);
-		if (ret)
-			break;
-	}
-	erofs_put_metabuf(&buf);
-	return ret;
-}
-#else
-static int erofs_load_compr_cfgs(struct super_block *sb,
-				 struct erofs_super_block *dsb)
-{
-	if (dsb->u1.available_compr_algs) {
-		erofs_err(sb, "try to load compressed fs when compression is disabled");
-		return -EINVAL;
-	}
-	return 0;
+	erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
+	return -EOPNOTSUPP;
 }
 #endif
 
@@ -406,10 +353,7 @@ static int erofs_read_superblock(struct super_block *sb)
 	}
 
 	/* parse on-disk compression configurations */
-	if (erofs_sb_has_compr_cfgs(sbi))
-		ret = erofs_load_compr_cfgs(sb, dsb);
-	else
-		ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	ret = z_erofs_parse_cfgs(sb, dsb);
 	if (ret < 0)
 		goto out;
 
-- 
2.30.2

[PATCH v2] erofs: simplify compression configuration parser

[Gao Xiang]

From: Gao Xiang <hsiangkao@linux.alibaba.com>

Move erofs_load_compr_cfgs() into decompressor.c as well as introduce
a callback instead of a hard-coded switch for each algorithm for
simplicity.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
v2:
 - fix build warning of `-Wmissing-declarations`
   https://lore.kernel.org/r/202310221347.8YPc9FUC-lkp@intel.com

 fs/erofs/compress.h             |  6 +++
 fs/erofs/decompressor.c         | 62 ++++++++++++++++++++++++++--
 fs/erofs/decompressor_deflate.c |  5 ++-
 fs/erofs/decompressor_lzma.c    |  4 +-
 fs/erofs/internal.h             | 38 +----------------
 fs/erofs/super.c                | 72 ++++-----------------------------
 6 files changed, 79 insertions(+), 108 deletions(-)

diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
index 349c3316ae6b..279933e007d2 100644
--- a/fs/erofs/compress.h
+++ b/fs/erofs/compress.h
@@ -21,6 +21,8 @@ struct z_erofs_decompress_req {
 };
 
 struct z_erofs_decompressor {
+	int (*config)(struct super_block *sb, struct erofs_super_block *dsb,
+		      void *data, int size);
 	int (*decompress)(struct z_erofs_decompress_req *rq,
 			  struct page **pagepool);
 	char *name;
@@ -92,6 +94,10 @@ int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
 extern const struct z_erofs_decompressor erofs_decompressors[];
 
 /* prototypes for specific algorithms */
+int z_erofs_load_lzma_config(struct super_block *sb,
+			struct erofs_super_block *dsb, void *data, int size);
+int z_erofs_load_deflate_config(struct super_block *sb,
+			struct erofs_super_block *dsb, void *data, int size);
 int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
 			    struct page **pagepool);
 int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 332ec5f74002..e75edc8f1753 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -24,11 +24,11 @@ struct z_erofs_lz4_decompress_ctx {
 	unsigned int oend;
 };
 
-int z_erofs_load_lz4_config(struct super_block *sb,
-			    struct erofs_super_block *dsb,
-			    struct z_erofs_lz4_cfgs *lz4, int size)
+static int z_erofs_load_lz4_config(struct super_block *sb,
+			    struct erofs_super_block *dsb, void *data, int size)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct z_erofs_lz4_cfgs *lz4 = data;
 	u16 distance;
 
 	if (lz4) {
@@ -370,19 +370,75 @@ const struct z_erofs_decompressor erofs_decompressors[] = {
 		.name = "interlaced"
 	},
 	[Z_EROFS_COMPRESSION_LZ4] = {
+		.config = z_erofs_load_lz4_config,
 		.decompress = z_erofs_lz4_decompress,
 		.name = "lz4"
 	},
 #ifdef CONFIG_EROFS_FS_ZIP_LZMA
 	[Z_EROFS_COMPRESSION_LZMA] = {
+		.config = z_erofs_load_lzma_config,
 		.decompress = z_erofs_lzma_decompress,
 		.name = "lzma"
 	},
 #endif
 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
 	[Z_EROFS_COMPRESSION_DEFLATE] = {
+		.config = z_erofs_load_deflate_config,
 		.decompress = z_erofs_deflate_decompress,
 		.name = "deflate"
 	},
 #endif
 };
+
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+	unsigned int algs, alg;
+	erofs_off_t offset;
+	int size, ret = 0;
+
+	if (!erofs_sb_has_compr_cfgs(sbi)) {
+		sbi->available_compr_algs = Z_EROFS_COMPRESSION_LZ4;
+		return z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	}
+
+	sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
+	if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
+		erofs_err(sb, "unidentified algorithms %x, please upgrade kernel",
+			  sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
+		return -EOPNOTSUPP;
+	}
+
+	erofs_init_metabuf(&buf, sb);
+	offset = EROFS_SUPER_OFFSET + sbi->sb_size;
+	alg = 0;
+	for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
+		void *data;
+
+		if (!(algs & 1))
+			continue;
+
+		data = erofs_read_metadata(sb, &buf, &offset, &size);
+		if (IS_ERR(data)) {
+			ret = PTR_ERR(data);
+			break;
+		}
+
+		if (alg >= ARRAY_SIZE(erofs_decompressors) ||
+		    !erofs_decompressors[alg].config) {
+			erofs_err(sb, "algorithm %d isn't enabled on this kernel",
+				  alg);
+			ret = -EOPNOTSUPP;
+		} else {
+			ret = erofs_decompressors[alg].config(sb,
+					dsb, data, size);
+		}
+
+		kfree(data);
+		if (ret)
+			break;
+	}
+	erofs_put_metabuf(&buf);
+	return ret;
+}
diff --git a/fs/erofs/decompressor_deflate.c b/fs/erofs/decompressor_deflate.c
index 19e5bdeb30b6..0e1946a6bda5 100644
--- a/fs/erofs/decompressor_deflate.c
+++ b/fs/erofs/decompressor_deflate.c
@@ -77,9 +77,10 @@ int __init z_erofs_deflate_init(void)
 }
 
 int z_erofs_load_deflate_config(struct super_block *sb,
-				struct erofs_super_block *dsb,
-				struct z_erofs_deflate_cfgs *dfl, int size)
+			struct erofs_super_block *dsb, void *data, int size)
 {
+	struct z_erofs_deflate_cfgs *dfl = data;
+
 	if (!dfl || size < sizeof(struct z_erofs_deflate_cfgs)) {
 		erofs_err(sb, "invalid deflate cfgs, size=%u", size);
 		return -EINVAL;
diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
index 5f413f19a064..852dd8eac5df 100644
--- a/fs/erofs/decompressor_lzma.c
+++ b/fs/erofs/decompressor_lzma.c
@@ -72,10 +72,10 @@ int __init z_erofs_lzma_init(void)
 }
 
 int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size)
+			struct erofs_super_block *dsb, void *data, int size)
 {
 	static DEFINE_MUTEX(lzma_resize_mutex);
+	struct z_erofs_lzma_cfgs *lzma = data;
 	unsigned int dict_size, i;
 	struct z_erofs_lzma *strm, *head = NULL;
 	int err;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 4ff88d0dd980..d8de61350dc0 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -469,9 +469,6 @@ int __init z_erofs_init_zip_subsystem(void);
 void z_erofs_exit_zip_subsystem(void);
 int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
 				       struct erofs_workgroup *egrp);
-int z_erofs_load_lz4_config(struct super_block *sb,
-			    struct erofs_super_block *dsb,
-			    struct z_erofs_lz4_cfgs *lz4, int len);
 int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
 			    int flags);
 void *erofs_get_pcpubuf(unsigned int requiredpages);
@@ -480,6 +477,7 @@ int erofs_pcpubuf_growsize(unsigned int nrpages);
 void __init erofs_pcpubuf_init(void);
 void erofs_pcpubuf_exit(void);
 int erofs_init_managed_cache(struct super_block *sb);
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb);
 #else
 static inline void erofs_shrinker_register(struct super_block *sb) {}
 static inline void erofs_shrinker_unregister(struct super_block *sb) {}
@@ -487,16 +485,6 @@ static inline int erofs_init_shrinker(void) { return 0; }
 static inline void erofs_exit_shrinker(void) {}
 static inline int z_erofs_init_zip_subsystem(void) { return 0; }
 static inline void z_erofs_exit_zip_subsystem(void) {}
-static inline int z_erofs_load_lz4_config(struct super_block *sb,
-				  struct erofs_super_block *dsb,
-				  struct z_erofs_lz4_cfgs *lz4, int len)
-{
-	if (lz4 || dsb->u1.lz4_max_distance) {
-		erofs_err(sb, "lz4 algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 static inline void erofs_pcpubuf_init(void) {}
 static inline void erofs_pcpubuf_exit(void) {}
 static inline int erofs_init_managed_cache(struct super_block *sb) { return 0; }
@@ -505,41 +493,17 @@ static inline int erofs_init_managed_cache(struct super_block *sb) { return 0; }
 #ifdef CONFIG_EROFS_FS_ZIP_LZMA
 int __init z_erofs_lzma_init(void);
 void z_erofs_lzma_exit(void);
-int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size);
 #else
 static inline int z_erofs_lzma_init(void) { return 0; }
 static inline int z_erofs_lzma_exit(void) { return 0; }
-static inline int z_erofs_load_lzma_config(struct super_block *sb,
-			     struct erofs_super_block *dsb,
-			     struct z_erofs_lzma_cfgs *lzma, int size) {
-	if (lzma) {
-		erofs_err(sb, "lzma algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 #endif	/* !CONFIG_EROFS_FS_ZIP_LZMA */
 
 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
 int __init z_erofs_deflate_init(void);
 void z_erofs_deflate_exit(void);
-int z_erofs_load_deflate_config(struct super_block *sb,
-				struct erofs_super_block *dsb,
-				struct z_erofs_deflate_cfgs *dfl, int size);
 #else
 static inline int z_erofs_deflate_init(void) { return 0; }
 static inline int z_erofs_deflate_exit(void) { return 0; }
-static inline int z_erofs_load_deflate_config(struct super_block *sb,
-			struct erofs_super_block *dsb,
-			struct z_erofs_deflate_cfgs *dfl, int size) {
-	if (dfl) {
-		erofs_err(sb, "deflate algorithm isn't enabled");
-		return -EINVAL;
-	}
-	return 0;
-}
 #endif	/* !CONFIG_EROFS_FS_ZIP_DEFLATE */
 
 #ifdef CONFIG_EROFS_FS_ONDEMAND
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 3700af9ee173..cc44fb2e001e 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -156,68 +156,15 @@ void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
 	return buffer;
 }
 
-#ifdef CONFIG_EROFS_FS_ZIP
-static int erofs_load_compr_cfgs(struct super_block *sb,
-				 struct erofs_super_block *dsb)
+#ifndef CONFIG_EROFS_FS_ZIP
+static int z_erofs_parse_cfgs(struct super_block *sb,
+			      struct erofs_super_block *dsb)
 {
-	struct erofs_sb_info *sbi = EROFS_SB(sb);
-	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
-	unsigned int algs, alg;
-	erofs_off_t offset;
-	int size, ret = 0;
-
-	sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
-	if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
-		erofs_err(sb, "try to load compressed fs with unsupported algorithms %x",
-			  sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
-		return -EINVAL;
-	}
-
-	erofs_init_metabuf(&buf, sb);
-	offset = EROFS_SUPER_OFFSET + sbi->sb_size;
-	alg = 0;
-	for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
-		void *data;
-
-		if (!(algs & 1))
-			continue;
-
-		data = erofs_read_metadata(sb, &buf, &offset, &size);
-		if (IS_ERR(data)) {
-			ret = PTR_ERR(data);
-			break;
-		}
+	if (!dsb->u1.available_compr_algs)
+		return 0;
 
-		switch (alg) {
-		case Z_EROFS_COMPRESSION_LZ4:
-			ret = z_erofs_load_lz4_config(sb, dsb, data, size);
-			break;
-		case Z_EROFS_COMPRESSION_LZMA:
-			ret = z_erofs_load_lzma_config(sb, dsb, data, size);
-			break;
-		case Z_EROFS_COMPRESSION_DEFLATE:
-			ret = z_erofs_load_deflate_config(sb, dsb, data, size);
-			break;
-		default:
-			DBG_BUGON(1);
-			ret = -EFAULT;
-		}
-		kfree(data);
-		if (ret)
-			break;
-	}
-	erofs_put_metabuf(&buf);
-	return ret;
-}
-#else
-static int erofs_load_compr_cfgs(struct super_block *sb,
-				 struct erofs_super_block *dsb)
-{
-	if (dsb->u1.available_compr_algs) {
-		erofs_err(sb, "try to load compressed fs when compression is disabled");
-		return -EINVAL;
-	}
-	return 0;
+	erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
+	return -EOPNOTSUPP;
 }
 #endif
 
@@ -406,10 +353,7 @@ static int erofs_read_superblock(struct super_block *sb)
 	}
 
 	/* parse on-disk compression configurations */
-	if (erofs_sb_has_compr_cfgs(sbi))
-		ret = erofs_load_compr_cfgs(sb, dsb);
-	else
-		ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+	ret = z_erofs_parse_cfgs(sb, dsb);
 	if (ret < 0)
 		goto out;
 
-- 
2.30.2

Re: [PATCH v2] erofs: simplify compression configuration parser

[Chao Yu]

On 2023/10/22 21:09, Gao Xiang wrote:
> From: Gao Xiang <hsiangkao@linux.alibaba.com>
> 
> Move erofs_load_compr_cfgs() into decompressor.c as well as introduce
> a callback instead of a hard-coded switch for each algorithm for
> simplicity.
> 
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,