From: Pankaj Raghav <p.raghav@xxxxxxxxxxx> Splitting a larger folio with a base order is supported using split_huge_page_to_list_to_order() API. However, using that API for LBS is resulting in an NULL ptr dereference error in the writeback path [1]. Refuse to split a folio if it has minimum folio order requirement until we can start using split_huge_page_to_list_to_order() API. Splitting the folio can be added as a later optimization. [1] https://gist.github.com/mcgrof/d12f586ec6ebe32b2472b5d634c397df Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx> Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx> --- mm/huge_memory.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9859aa4f7553..dadf1e68dbdc 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3117,6 +3117,15 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, goto out; } + /* + * Do not split if mapping has minimum folio order + * requirement. + */ + if (mapping_min_folio_order(mapping)) { + ret = -EINVAL; + goto out; + } + gfp = current_gfp_context(mapping_gfp_mask(mapping) & GFP_RECLAIM_MASK); -- 2.34.1
