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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: 3afc423632 ("mm: pagewalk: add p4d_entry() and pgd_entry()")
Cc: Steven Price <steven.price@arm.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Jason Gunthorpe 2020-03-02 15:26:44 -04:00
parent dfdc22078f
commit 05fc1df95e
1 changed files with 7 additions and 7 deletions
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14
mm/hmm.c
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@ -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);