[RFC PATCH 07/24] mm/memory: add range field to struct vm_fault

[Michel Lespinasse <walken@google.com>]

Add a range field to struct vm_fault. This carries the range that was
locked for the given fault.

Faults that release the mmap_sem should pass the specified range.

Signed-off-by: Michel Lespinasse <walken@google.com>
---
 include/linux/mm.h | 1 +
 mm/hugetlb.c       | 1 +
 mm/khugepaged.c    | 1 +
 mm/memory.c        | 1 +
 4 files changed, 4 insertions(+)

diff --git include/linux/mm.h include/linux/mm.h
index 052f423d7f67..a1c9a0aa898b 100644
--- include/linux/mm.h
+++ include/linux/mm.h
@@ -451,6 +451,7 @@ struct vm_fault {
 					 * page table to avoid allocation from
 					 * atomic context.
 					 */
+	struct mm_lock_range *range;	/* MM read lock range. */
 };
 
 /* page entry size for vm->huge_fault() */
diff --git mm/hugetlb.c mm/hugetlb.c
index dd8737a94bec..662f34b6c869 100644
--- mm/hugetlb.c
+++ mm/hugetlb.c
@@ -3831,6 +3831,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
 				.vma = vma,
 				.address = haddr,
 				.flags = flags,
+				.range = mm_coarse_lock_range(),
 				/*
 				 * Hard to debug if it ends up being
 				 * used by a callee that assumes
diff --git mm/khugepaged.c mm/khugepaged.c
index 7ee8ae64824b..a7807bb0d631 100644
--- mm/khugepaged.c
+++ mm/khugepaged.c
@@ -900,6 +900,7 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
 		.flags = FAULT_FLAG_ALLOW_RETRY,
 		.pmd = pmd,
 		.pgoff = linear_page_index(vma, address),
+		.range = mm_coarse_lock_range(),
 	};
 
 	/* we only decide to swapin, if there is enough young ptes */
diff --git mm/memory.c mm/memory.c
index 45b42fa02a2e..6cb3359f0857 100644
--- mm/memory.c
+++ mm/memory.c
@@ -4047,6 +4047,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
 		.flags = flags,
 		.pgoff = linear_page_index(vma, address),
 		.gfp_mask = __get_fault_gfp_mask(vma),
+		.range = mm_coarse_lock_range(),
 	};
 	unsigned int dirty = flags & FAULT_FLAG_WRITE;
 	struct mm_struct *mm = vma->vm_mm;
-- 
2.25.0.341.g760bfbb309-goog