linux-kernel - [PATCH] erofs: simplify the code using for_each_set

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Message-ID: <tencent_CB6FE08BB14BB368855B6D7CC515EDFC2C05@qq.com>
Date: Wed, 17 Dec 2025 17:09:39 +0800
From: Yuwen Chen <ywen.chen@...mail.com>
To: xiang@...nel.org
Cc: chao@...nel.org,
	huyue2@...lpad.com,
	jefflexu@...ux.alibaba.com,
	linux-erofs@...ts.ozlabs.org,
	linux-kernel@...r.kernel.org,
	Yuwen Chen <ywen.chen@...mail.com>
Subject: [PATCH] erofs: simplify the code using for_each_set_bit

When mounting the EROFS file system, it is necessary to check the
available compression algorithms. At this time, the for_each_set_bit
function can be used to simplify the code logic.

Signed-off-by: Yuwen Chen <ywen.chen@...mail.com>
---
 fs/erofs/decompressor.c | 10 +++-------
 fs/erofs/internal.h     |  2 +-
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 2ec9b2bb628d6..93e7ae2e363ff 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -405,7 +405,7 @@ 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;
+	unsigned int alg;
 	erofs_off_t offset;
 	int size, ret = 0;
 
@@ -416,20 +416,16 @@ int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
 
 	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",
+		erofs_err(sb, "unidentified algorithms %lx, 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) {
+	for_each_set_bit(alg, &sbi->available_compr_algs, Z_EROFS_COMPRESSION_MAX) {
 		void *data;
 
-		if (!(algs & 1))
-			continue;
-
 		data = erofs_read_metadata(sb, &buf, &offset, &size);
 		if (IS_ERR(data)) {
 			ret = PTR_ERR(data);
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index c69174675caf7..c34cfcdf1e401 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -126,7 +126,7 @@ struct erofs_sb_info {
 	struct xarray managed_pslots;
 
 	unsigned int shrinker_run_no;
-	u16 available_compr_algs;
+	unsigned long available_compr_algs;
 
 	/* pseudo inode to manage cached pages */
 	struct inode *managed_cache;
-- 
2.34.1