Re: [PATCH v5 1/3] io_uring/rsrc: add hugepage fixed buffer coalesce helpers

[Chenliang Li <cliang01.li@samsung.com>]

On 2024-07-09 13:09 UTC, Pavel Begunkov wrote:
> On 6/28/24 09:44, Chenliang Li wrote:
>> +static bool io_try_coalesce_buffer(struct page ***pages, int *nr_pages,
>> +					 struct io_imu_folio_data *data)
>
> I believe unused static function will trigger a warning, we don't
> want that, especially since error on warn is a thing.
>
> You can either reshuffle patches or at least add a
> __maybe_unused attribute.

OK, will reshuffle the patchset.

>> +	/*
>> +	 * Check if pages are contiguous inside a folio, and all folios have
>> +	 * the same page count except for the head and tail.
>> +	 */
>> +	for (i = 1; i < *nr_pages; i++) {
>> +		if (page_folio(page_array[i]) == folio &&
>> +			page_array[i] == page_array[i-1] + 1) {
>> +			count++;
>> +			continue;
>> +		}
>
> Seems like the first and last folios can be not border aligned,
> i.e. the first should end at the folio_size boundary, and the
> last one should start at the beginning of the folio.
>
> Not really a bug, but we might get some problems with optimising
> calculations down the road if we don't restrict it.

Will add restrictions for that.

Thanks,
Chenliang Li