erofs: code clean up for fscache

Some cleanups. No logic changes.
Suggested-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220918043456.147-3-zhujia.zj@bytedance.comSigned-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

fs/erofs/fscache.c

@@ -421,9 +421,8 @@ const struct address_space_operations erofs_fscache_access_aops = {
 	.readahead = erofs_fscache_readahead,
 };
 
-int erofs_fscache_register_cookie(struct super_block *sb,
-				  struct erofs_fscache **fscache,
-				  char *name, bool need_inode)
+struct erofs_fscache *erofs_fscache_register_cookie(struct super_block *sb,
+						     char *name, bool need_inode)
 {
 	struct fscache_volume *volume = EROFS_SB(sb)->volume;
 	struct erofs_fscache *ctx;
@@ -432,7 +431,7 @@ int erofs_fscache_register_cookie(struct super_block *sb,
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	cookie = fscache_acquire_cookie(volume, FSCACHE_ADV_WANT_CACHE_SIZE,
 					name, strlen(name), NULL, 0, 0);
@@ -462,42 +461,33 @@ int erofs_fscache_register_cookie(struct super_block *sb,
 		ctx->inode = inode;
 	}
 
-	*fscache = ctx;
-	return 0;
+	return ctx;
 
 err_cookie:
 	fscache_unuse_cookie(ctx->cookie, NULL, NULL);
 	fscache_relinquish_cookie(ctx->cookie, false);
-	ctx->cookie = NULL;
 err:
 	kfree(ctx);
-	return ret;
+	return ERR_PTR(ret);
 }
 
-void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
+void erofs_fscache_unregister_cookie(struct erofs_fscache *ctx)
 {
-	struct erofs_fscache *ctx = *fscache;
-
 	if (!ctx)
 		return;
 
 	fscache_unuse_cookie(ctx->cookie, NULL, NULL);
 	fscache_relinquish_cookie(ctx->cookie, false);
-	ctx->cookie = NULL;
-
 	iput(ctx->inode);
-	ctx->inode = NULL;
-
 	kfree(ctx);
-	*fscache = NULL;
 }
 
 int erofs_fscache_register_fs(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 	struct fscache_volume *volume;
+	struct erofs_fscache *fscache;
 	char *name;
-	int ret = 0;
 
 	name = kasprintf(GFP_KERNEL, "erofs,%s", sbi->opt.fsid);
 	if (!name)
@@ -506,19 +496,28 @@ int erofs_fscache_register_fs(struct super_block *sb)
 	volume = fscache_acquire_volume(name, NULL, NULL, 0);
 	if (IS_ERR_OR_NULL(volume)) {
 		erofs_err(sb, "failed to register volume for %s", name);
-		ret = volume ? PTR_ERR(volume) : -EOPNOTSUPP;
-		volume = NULL;
+		kfree(name);
+		return volume ? PTR_ERR(volume) : -EOPNOTSUPP;
 	}
 
 	sbi->volume = volume;
 	kfree(name);
-	return ret;
+
+	fscache = erofs_fscache_register_cookie(sb, sbi->opt.fsid, true);
+	/* acquired volume will be relinquished in kill_sb() */
+	if (IS_ERR(fscache))
+		return PTR_ERR(fscache);
+
+	sbi->s_fscache = fscache;
+	return 0;
 }
 
 void erofs_fscache_unregister_fs(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 
+	erofs_fscache_unregister_cookie(sbi->s_fscache);
 	fscache_relinquish_volume(sbi->volume, NULL, false);
+	sbi->s_fscache = NULL;
 	sbi->volume = NULL;
 }

fs/erofs/internal.h

@@ -581,27 +581,26 @@ static inline int z_erofs_load_lzma_config(struct super_block *sb,
 int erofs_fscache_register_fs(struct super_block *sb);
 void erofs_fscache_unregister_fs(struct super_block *sb);
 
-int erofs_fscache_register_cookie(struct super_block *sb,
-				  struct erofs_fscache **fscache,
-				  char *name, bool need_inode);
-void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache);
+struct erofs_fscache *erofs_fscache_register_cookie(struct super_block *sb,
+						     char *name, bool need_inode);
+void erofs_fscache_unregister_cookie(struct erofs_fscache *fscache);
 
 extern const struct address_space_operations erofs_fscache_access_aops;
 #else
 static inline int erofs_fscache_register_fs(struct super_block *sb)
 {
-	return 0;
+	return -EOPNOTSUPP;
 }
 static inline void erofs_fscache_unregister_fs(struct super_block *sb) {}
 
-static inline int erofs_fscache_register_cookie(struct super_block *sb,
-						struct erofs_fscache **fscache,
-						char *name, bool need_inode)
+static inline
+struct erofs_fscache *erofs_fscache_register_cookie(struct super_block *sb,
+						     char *name, bool need_inode)
 {
-	return -EOPNOTSUPP;
+	return ERR_PTR(-EOPNOTSUPP);
 }
 
-static inline void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
+static inline void erofs_fscache_unregister_cookie(struct erofs_fscache *fscache)
 {
 }
 #endif

fs/erofs/super.c

@@ -224,10 +224,10 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
 			     struct erofs_device_info *dif, erofs_off_t *pos)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_fscache *fscache;
 	struct erofs_deviceslot *dis;
 	struct block_device *bdev;
 	void *ptr;
-	int ret;
 
 	ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*pos), EROFS_KMAP);
 	if (IS_ERR(ptr))
@@ -245,10 +245,10 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
 	}
 
 	if (erofs_is_fscache_mode(sb)) {
-		ret = erofs_fscache_register_cookie(sb, &dif->fscache,
-				dif->path, false);
-		if (ret)
-			return ret;
+		fscache = erofs_fscache_register_cookie(sb, dif->path, false);
+		if (IS_ERR(fscache))
+			return PTR_ERR(fscache);
+		dif->fscache = fscache;
 	} else {
 		bdev = blkdev_get_by_path(dif->path, FMODE_READ | FMODE_EXCL,
 					  sb->s_type);
@@ -706,11 +706,6 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 		if (err)
 			return err;
 
-		err = erofs_fscache_register_cookie(sb, &sbi->s_fscache,
-						    sbi->opt.fsid, true);
-		if (err)
-			return err;
-
 		err = super_setup_bdi(sb);
 		if (err)
 			return err;
@@ -817,7 +812,8 @@ static int erofs_release_device_info(int id, void *ptr, void *data)
 	fs_put_dax(dif->dax_dev, NULL);
 	if (dif->bdev)
 		blkdev_put(dif->bdev, FMODE_READ | FMODE_EXCL);
-	erofs_fscache_unregister_cookie(&dif->fscache);
+	erofs_fscache_unregister_cookie(dif->fscache);
+	dif->fscache = NULL;
 	kfree(dif->path);
 	kfree(dif);
 	return 0;
@@ -889,7 +885,6 @@ static void erofs_kill_sb(struct super_block *sb)
 
 	erofs_free_dev_context(sbi->devs);
 	fs_put_dax(sbi->dax_dev, NULL);
-	erofs_fscache_unregister_cookie(&sbi->s_fscache);
 	erofs_fscache_unregister_fs(sb);
 	kfree(sbi->opt.fsid);
 	kfree(sbi);
@@ -909,7 +904,7 @@ static void erofs_put_super(struct super_block *sb)
 	iput(sbi->managed_cache);
 	sbi->managed_cache = NULL;
 #endif
-	erofs_fscache_unregister_cookie(&sbi->s_fscache);
+	erofs_fscache_unregister_fs(sb);
 }
 
 static struct file_system_type erofs_fs_type = {