Commit 05fc1df9 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

mm/hmm: do not call hmm_vma_walk_hole() while holding a spinlock 



This eventually calls into handle_mm_fault() which is a sleeping function.
Release the lock first.

hmm_vma_walk_hole() does not touch the contents of the PUD, so it does not
need the lock.

Fixes: 3afc4236 ("mm: pagewalk: add p4d_entry() and pgd_entry()")
Cc: Steven Price <steven.price@arm.com>
Reviewed-by: default avatarRalph Campbell <rcampbell@nvidia.com>
Reviewed-by: default avatarSteven Price <steven.price@arm.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent dfdc2207

mm/hmm.c

+7 −7
Original line number Diff line number Diff line
@@ -491,8 +491,8 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, 


	pud = READ_ONCE(*pudp);

	if (pud_none(pud)) {

		ret = hmm_vma_walk_hole(start, end, -1, walk);

		goto out_unlock;

		spin_unlock(ptl);

		return hmm_vma_walk_hole(start, end, -1, walk);

	}



	if (pud_huge(pud) && pud_devmap(pud)) {
@@ -501,8 +501,8 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, 
		bool fault, write_fault;



		if (!pud_present(pud)) {

			ret = hmm_vma_walk_hole(start, end, -1, walk);

			goto out_unlock;

			spin_unlock(ptl);

			return hmm_vma_walk_hole(start, end, -1, walk);

		}



		i = (addr - range->start) >> PAGE_SHIFT;
@@ -513,9 +513,9 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, 
		hmm_range_need_fault(hmm_vma_walk, pfns, npages,

				     cpu_flags, &fault, &write_fault);

		if (fault || write_fault) {

			ret = hmm_vma_walk_hole_(addr, end, fault,

						 write_fault, walk);

			goto out_unlock;

			spin_unlock(ptl);

			return hmm_vma_walk_hole_(addr, end, fault, write_fault,

						  walk);

		}



		pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);

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