Commit 19066e58 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

exec: use VMA iterator instead of linked list 

Remove a use of the vm_next list by doing the initial lookup with the VMA
iterator and then using it to find the next entry.

Link: https://lkml.kernel.org/r/20220906194824.2110408-42-Liam.Howlett@oracle.com


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: default avatarYu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 182ea1d7

fs/exec.c

+6 −3
Original line number Diff line number Diff line
@@ -683,6 +683,8 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) 
	unsigned long length = old_end - old_start;

	unsigned long new_start = old_start - shift;

	unsigned long new_end = old_end - shift;

	VMA_ITERATOR(vmi, mm, new_start);

	struct vm_area_struct *next;

	struct mmu_gather tlb;



	BUG_ON(new_start > new_end);
@@ -691,7 +693,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) 
	 * ensure there are no vmas between where we want to go

	 * and where we are

	 */

	if (vma != find_vma(mm, new_start))

	if (vma != vma_next(&vmi))

		return -EFAULT;



	/*
@@ -710,12 +712,13 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) 


	lru_add_drain();

	tlb_gather_mmu(&tlb, mm);

	next = vma_next(&vmi);

	if (new_end > old_start) {

		/*

		 * when the old and new regions overlap clear from new_end.

		 */

		free_pgd_range(&tlb, new_end, old_end, new_end,

			vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING);

			next ? next->vm_start : USER_PGTABLES_CEILING);

	} else {

		/*

		 * otherwise, clean from old_start; this is done to not touch
@@ -724,7 +727,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) 
		 * for the others its just a little faster.

		 */

		free_pgd_range(&tlb, old_start, old_end, new_end,

			vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING);

			next ? next->vm_start : USER_PGTABLES_CEILING);

	}

	tlb_finish_mmu(&tlb);