From 5504ed29692faad06ea74c4275e96a8ffc83a1e1 Mon Sep 17 00:00:00 2001 From: Jérôme Glisse Date: Tue, 10 Apr 2018 16:28:46 -0700 Subject: mm/hmm: do not differentiate between empty entry or missing directory There is no point in differentiating between a range for which there is not even a directory (and thus entries) and empty entry (pte_none() or pmd_none() returns true). Simply drop the distinction ie remove HMM_PFN_EMPTY flag and merge now duplicate hmm_vma_walk_hole() and hmm_vma_walk_clear() functions. Link: http://lkml.kernel.org/r/20180323005527.758-11-jglisse@redhat.com Signed-off-by: Jérôme Glisse Reviewed-by: John Hubbard Cc: Evgeny Baskakov Cc: Ralph Campbell Cc: Mark Hairgrove Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hmm.c | 45 +++++++++++++++------------------------------ 1 file changed, 15 insertions(+), 30 deletions(-) (limited to 'mm') diff --git a/mm/hmm.c b/mm/hmm.c index a93c1e35df91..b8affe0bf4eb 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -348,6 +348,16 @@ static void hmm_pfns_clear(uint64_t *pfns, *pfns = 0; } +/* + * hmm_vma_walk_hole() - handle a range lacking valid pmd or pte(s) + * @start: range virtual start address (inclusive) + * @end: range virtual end address (exclusive) + * @walk: mm_walk structure + * Returns: 0 on success, -EAGAIN after page fault, or page fault error + * + * This function will be called whenever pmd_none() or pte_none() returns true, + * or whenever there is no page directory covering the virtual address range. + */ static int hmm_vma_walk_hole(unsigned long addr, unsigned long end, struct mm_walk *walk) @@ -357,31 +367,6 @@ static int hmm_vma_walk_hole(unsigned long addr, uint64_t *pfns = range->pfns; unsigned long i; - hmm_vma_walk->last = addr; - i = (addr - range->start) >> PAGE_SHIFT; - for (; addr < end; addr += PAGE_SIZE, i++) { - pfns[i] = HMM_PFN_EMPTY; - if (hmm_vma_walk->fault) { - int ret; - - ret = hmm_vma_do_fault(walk, addr, &pfns[i]); - if (ret != -EAGAIN) - return ret; - } - } - - return hmm_vma_walk->fault ? -EAGAIN : 0; -} - -static int hmm_vma_walk_clear(unsigned long addr, - unsigned long end, - struct mm_walk *walk) -{ - struct hmm_vma_walk *hmm_vma_walk = walk->private; - struct hmm_range *range = hmm_vma_walk->range; - uint64_t *pfns = range->pfns; - unsigned long i; - hmm_vma_walk->last = addr; i = (addr - range->start) >> PAGE_SHIFT; for (; addr < end; addr += PAGE_SIZE, i++) { @@ -440,10 +425,10 @@ again: if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) goto again; if (pmd_protnone(pmd)) - return hmm_vma_walk_clear(start, end, walk); + return hmm_vma_walk_hole(start, end, walk); if (write_fault && !pmd_write(pmd)) - return hmm_vma_walk_clear(start, end, walk); + return hmm_vma_walk_hole(start, end, walk); pfn = pmd_pfn(pmd) + pte_index(addr); flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0; @@ -462,7 +447,7 @@ again: pfns[i] = 0; if (pte_none(pte)) { - pfns[i] = HMM_PFN_EMPTY; + pfns[i] = 0; if (hmm_vma_walk->fault) goto fault; continue; @@ -513,8 +498,8 @@ again: fault: pte_unmap(ptep); - /* Fault all pages in range */ - return hmm_vma_walk_clear(start, end, walk); + /* Fault any virtual address we were asked to fault */ + return hmm_vma_walk_hole(start, end, walk); } pte_unmap(ptep - 1); -- cgit v1.2.3