Commit 61a4b8d3 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: move FAULT_FLAG_VMA_LOCK check down from do_fault() 

Perform the check at the start of do_read_fault(), do_cow_fault() and
do_shared_fault() instead.  Should be no performance change from the last
commit.

Link: https://lkml.kernel.org/r/20230724185410.1124082-8-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarSuren Baghdasaryan <surenb@google.com>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0c2e394a

mm/memory.c

+15 −5
Original line number Diff line number Diff line
@@ -4533,6 +4533,11 @@ static vm_fault_t do_read_fault(struct vm_fault *vmf) 
	vm_fault_t ret = 0;

	struct folio *folio;



	if (vmf->flags & FAULT_FLAG_VMA_LOCK) {

		vma_end_read(vmf->vma);

		return VM_FAULT_RETRY;

	}



	/*

	 * Let's call ->map_pages() first and use ->fault() as fallback

	 * if page by the offset is not ready to be mapped (cold cache or
@@ -4561,6 +4566,11 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf) 
	struct vm_area_struct *vma = vmf->vma;

	vm_fault_t ret;



	if (vmf->flags & FAULT_FLAG_VMA_LOCK) {

		vma_end_read(vma);

		return VM_FAULT_RETRY;

	}



	if (unlikely(anon_vma_prepare(vma)))

		return VM_FAULT_OOM;
@@ -4601,6 +4611,11 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf) 
	vm_fault_t ret, tmp;

	struct folio *folio;



	if (vmf->flags & FAULT_FLAG_VMA_LOCK) {

		vma_end_read(vma);

		return VM_FAULT_RETRY;

	}



	ret = __do_fault(vmf);

	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))

		return ret;
@@ -4647,11 +4662,6 @@ static vm_fault_t do_fault(struct vm_fault *vmf) 
	struct mm_struct *vm_mm = vma->vm_mm;

	vm_fault_t ret;



	if (vmf->flags & FAULT_FLAG_VMA_LOCK){

		vma_end_read(vma);

		return VM_FAULT_RETRY;

	}



	/*

	 * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND

	 */