From 9f454612f602d02204b1f6e86b6bec2bfb368c4b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= Date: Mon, 13 May 2019 17:19:52 -0700 Subject: [PATCH] mm/hmm: do not erase snapshot when a range is invalidated MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Users of HMM might be using the snapshot information to do preparatory step like dma mapping pages to a device before checking for invalidation through hmm_vma_range_done() so do not erase that information and assume users will do the right thing. Link: http://lkml.kernel.org/r/20190403193318.16478-4-jglisse@redhat.com Signed-off-by: Jérôme Glisse Reviewed-by: Ralph Campbell Reviewed-by: John Hubbard Cc: Dan Williams Cc: Arnd Bergmann Cc: Balbir Singh Cc: Dan Carpenter Cc: Ira Weiny Cc: Matthew Wilcox Cc: Souptick Joarder Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hmm.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/mm/hmm.c b/mm/hmm.c index 919d78fd21c5..84e0577a912a 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -174,16 +174,10 @@ static int hmm_invalidate_range(struct hmm *hmm, bool device, spin_lock(&hmm->lock); list_for_each_entry(range, &hmm->ranges, list) { - unsigned long addr, idx, npages; - if (update->end < range->start || update->start >= range->end) continue; range->valid = false; - addr = max(update->start, range->start); - idx = (addr - range->start) >> PAGE_SHIFT; - npages = (min(range->end, update->end) - addr) >> PAGE_SHIFT; - memset(&range->pfns[idx], 0, sizeof(*range->pfns) * npages); } spin_unlock(&hmm->lock);