On Thu, Oct 03, 2019 at 01:18:55PM -0700, Davidlohr Bueso wrote: > +++ b/mm/nommu.c > @@ -1793,7 +1793,7 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size, > size_t r_size, r_top; > > low = newsize >> PAGE_SHIFT; > - high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; > + high = (size + PAGE_SIZE) >> PAGE_SHIFT; Uhh ... are you sure about this? size is in bytes here, and we're rounding up to the next page size. So if size is [1-4096], then we add on 4095 and get the answer 1. With your patch, if size is [0-4095], we get the answer 1. I think you meant: high = ((size + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;
