Re: [PATCH 1/2] mm: move filemap_range_needs_writeback() into header

[Matthew Wilcox <willy@infradead.org>]

On Fri, Dec 03, 2021 at 08:38:28AM -0700, Jens Axboe wrote:
> +++ b/include/linux/fs.h

fs.h is the wrong place for these functions; they're pagecache
functionality, so they should be in pagemap.h.

> +/* Returns true if writeback might be needed or already in progress. */
> +static inline bool mapping_needs_writeback(struct address_space *mapping)
> +{
> +	return mapping->nrpages;
> +}

I don't like this function -- mapping_needs_writeback says to me that it
tests a flag in mapping->flags.  Plus, it does exactly the same thing as
!mapping_empty(), so perhaps ...

> +static inline bool filemap_range_needs_writeback(struct address_space *mapping,
> +						 loff_t start_byte,
> +						 loff_t end_byte)
> +{
> +	if (!mapping_needs_writeback(mapping))
> +		return false;

just make this
	if (mapping_empty(mapping))
		return false;

Other than that, no objections to making this static inline.