On Fri, Oct 13, 2017 at 04:09:23PM -0400, Nicolas Pitre wrote: > On Fri, 13 Oct 2017, Al Viro wrote: > > > OK... I wonder if it should simply define stubs for kill_mtd_super(), > > mtd_unpoint() and kill_block_super() in !CONFIG_MTD and !CONFIG_BLOCK > > cases. mount_mtd() and mount_bdev() as well - e.g. mount_bdev() > > returning ERR_PTR(-ENODEV) and kill_block_super() being simply BUG() > > in !CONFIG_BLOCK case. Then cramfs_kill_sb() would be > > if (sb->s_mtd) { > > if (sbi->mtd_point_size) > > mtd_unpoint(sb->s_mtd, 0, sbi->mtd_point_size); > > kill_mtd_super(sb); > > } else { > > kill_block_super(sb); > > } > > kfree(sbi); > > Well... Stubs have to be named differently or they conflict with > existing declarations. At that point that makes for more lines of code > compared to the current patch and the naming indirection makes it less > obvious when reading the code. Alternatively I could add those stubs in > the corresponding header files and #ifdef the existing declarations > away. That might look somewhat less cluttered in the main code but it > also hides what is actually going on and left me unconvinced. And I'm > not sure this is worth it in the end given this is not a common > occurrence in the kernel either. What I mean is this (completely untested) for CONFIG_BLOCK side of things, with something similar for CONFIG_MTD one: Provide definitions of mount_bdev/kill_block_super() in case !CONFIG_BLOCK mount_bdev() and kill_block_super() are defined only when CONFIG_BLOCK is defined; however, their declarations in fs.h are unconditional. We could make these conditional upon CONFIG_BLOCK as well, but it's easy to provide inline definitions for !CONFIG_BLOCK case - mount_bdev() should fail with ENODEV, while kill_block_super() can be simply BUG(); there should be no superblock instances with non-NULL ->s_bdev on such configs. Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> --- diff --git a/include/linux/fs.h b/include/linux/fs.h index 339e73742e73..e773c1c51aad 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2094,9 +2094,18 @@ struct file_system_type { extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags, void *data, void *ns, struct user_namespace *user_ns, int (*fill_super)(struct super_block *, void *, int)); +#ifdef CONFIG_BLOCK extern struct dentry *mount_bdev(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, int (*fill_super)(struct super_block *, void *, int)); +#else +static inline struct dentry *mount_bdev(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data, + int (*fill_super)(struct super_block *, void *, int)) +{ + return ERR_PTR(-ENODEV); +} +#endif extern struct dentry *mount_single(struct file_system_type *fs_type, int flags, void *data, int (*fill_super)(struct super_block *, void *, int)); @@ -2105,7 +2114,14 @@ extern struct dentry *mount_nodev(struct file_system_type *fs_type, int (*fill_super)(struct super_block *, void *, int)); extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path); void generic_shutdown_super(struct super_block *sb); +#ifdef CONFIG_BLOCK void kill_block_super(struct super_block *sb); +#else +static inline void kill_block_super(struct super_block *sb) +{ + BUG(); +} +#endif void kill_anon_super(struct super_block *sb); void kill_litter_super(struct super_block *sb); void deactivate_super(struct super_block *sb); -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html