From 986f5f2b4be3b7eab9ecd85c472d03a2191d6fc0 Mon Sep 17 00:00:00 2001 From: Vivek Kasireddy Date: Tue, 17 Jun 2025 22:30:53 -0700 Subject: mm/hugetlb: make hugetlb_reserve_pages() return nr of entries updated Patch series "mm/memfd: Reserve hugetlb folios before allocation", v4. There are cases when we try to pin a folio but discover that it has not been faulted-in. So, we try to allocate it in memfd_alloc_folio() but the allocation request may not succeed if there are no active reservations in the system at that instant. Therefore, making a reservation (by calling hugetlb_reserve_pages()) associated with the allocation will ensure that our request would not fail due to lack of reservations. This will also ensure that proper region/subpool accounting is done with our allocation. This patch (of 3): Currently, hugetlb_reserve_pages() returns a bool to indicate whether the reservation map update for the range [from, to] was successful or not. This is not sufficient for the case where the caller needs to determine how many entries were updated for the range. Therefore, have hugetlb_reserve_pages() return the number of entries updated in the reservation map associated with the range [from, to]. Also, update the callers of hugetlb_reserve_pages() to handle the new return value. Link: https://lkml.kernel.org/r/20250618053415.1036185-1-vivek.kasireddy@intel.com Link: https://lkml.kernel.org/r/20250618053415.1036185-2-vivek.kasireddy@intel.com Signed-off-by: Vivek Kasireddy Cc: Steve Sistare Cc: Muchun Song Cc: David Hildenbrand Cc: Gerd Hoffmann Cc: Oscar Salvador Signed-off-by: Andrew Morton --- include/linux/hugetlb.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 42f374e828a2..d8310b0f36dd 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -149,7 +149,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, uffd_flags_t flags, struct folio **foliop); #endif /* CONFIG_USERFAULTFD */ -bool hugetlb_reserve_pages(struct inode *inode, long from, long to, +long hugetlb_reserve_pages(struct inode *inode, long from, long to, struct vm_area_struct *vma, vm_flags_t vm_flags); long hugetlb_unreserve_pages(struct inode *inode, long start, long end, -- cgit v1.2.3