On 12/3/21 9:31 AM, Jens Axboe wrote:
> On 12/3/21 9:24 AM, Jens Axboe wrote:
>> On 12/3/21 9:16 AM, Matthew Wilcox wrote:
>>> 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.
>>
>> Good idea, I'll make that change.
>
> That does introduce a dependency from fs.h -> pagemap.h which isn't trivially
> resolvable...
>
> What if we just rename the above funciton to mapping_has_pages() or something
> instead?
Or just drop the helper, to be honest. There are more tests for mapping->nrpages
right now than there are callers of this silly little helper.
--
Jens Axboe
