Re: [PATCH v6 05/37] fs: Convert alloc_inode_sb() to a macro

[Andrew Morton]

On Thu, 21 Mar 2024 09:36:27 -0700 Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote:

> From: Kent Overstreet <kent.overstreet@xxxxxxxxx>
> 
> We're introducing alloc tagging, which tracks memory allocations by
> callsite. Converting alloc_inode_sb() to a macro means allocations will
> be tracked by its caller, which is a bit more useful.

I'd have thought that there would be many similar
inlines-which-allocate-memory.  Such as, I dunno, jbd2_alloc_inode(). 
Do we have to go converting things to macros as people report
misleading or less useful results, or is there some more general
solution to this?

> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3083,11 +3083,7 @@ int setattr_should_drop_sgid(struct mnt_idmap *idmap,
>   * This must be used for allocating filesystems specific inodes to set
>   * up the inode reclaim context correctly.
>   */
> -static inline void *
> -alloc_inode_sb(struct super_block *sb, struct kmem_cache *cache, gfp_t gfp)
> -{
> -	return kmem_cache_alloc_lru(cache, &sb->s_inode_lru, gfp);
> -}
> +#define alloc_inode_sb(_sb, _cache, _gfp) kmem_cache_alloc_lru(_cache, &_sb->s_inode_lru, _gfp)

Parenthesizing __sb seems sensible here?