On 3/11/20 11:35 AM, Jason Gunthorpe wrote:
From: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
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: 3afc423632a1 ("mm: pagewalk: add p4d_entry() and pgd_entry()")
Cc: Steven Price <steven.price@xxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Reviewed-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
--- mm/hmm.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/mm/hmm.c b/mm/hmm.c index 9e8f68eb83287a..32dcbfd3908315 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -473,8 +473,8 @@ 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)) {@@ -483,8 +483,8 @@ 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;@@ -495,9 +495,9 @@ 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);
