| Message ID | 20200708012453.36588-5-richard.weiyang@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/mremap: cleanup move_page_tables() a little | expand |
On Wed, Jul 08, 2020 at 09:24:53AM +0800, Wei Yang wrote: > The purpose of this code is to calculate the smaller extent in old and > new range. Let's leverage pmd_addr_end() to do the calculation. > > Hope this would make the code easier to read. > > Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> > --- > mm/mremap.c | 16 +++++++--------- > 1 file changed, 7 insertions(+), 9 deletions(-) > > diff --git a/mm/mremap.c b/mm/mremap.c > index f5f17d050617..76e7fdf567c3 100644 > --- a/mm/mremap.c > +++ b/mm/mremap.c > @@ -237,11 +237,12 @@ unsigned long move_page_tables(struct vm_area_struct *vma, > unsigned long new_addr, unsigned long len, > bool need_rmap_locks) > { > - unsigned long extent, next, old_end; > + unsigned long extent, old_next, new_next, old_end, new_end; > struct mmu_notifier_range range; > pmd_t *old_pmd, *new_pmd; > > old_end = old_addr + len; > + new_end = new_addr + len; > flush_cache_range(vma, old_addr, old_end); > > mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm, > @@ -250,14 +251,11 @@ unsigned long move_page_tables(struct vm_area_struct *vma, > > for (; old_addr < old_end; old_addr += extent, new_addr += extent) { > cond_resched(); > - next = (old_addr + PMD_SIZE) & PMD_MASK; > - /* even if next overflowed, extent below will be ok */ > - extent = next - old_addr; > - if (extent > old_end - old_addr) > - extent = old_end - old_addr; > - next = (new_addr + PMD_SIZE) & PMD_MASK; > - if (extent > next - new_addr) > - extent = next - new_addr; > + > + old_next = pmd_addr_end(old_addr, old_end); > + new_next = pmd_addr_end(new_addr, new_end); > + extent = min((old_next - old_addr), (new_next - new_addr)); Nit: redundant parentheses.
diff --git a/mm/mremap.c b/mm/mremap.c index f5f17d050617..76e7fdf567c3 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -237,11 +237,12 @@ unsigned long move_page_tables(struct vm_area_struct *vma, unsigned long new_addr, unsigned long len, bool need_rmap_locks) { - unsigned long extent, next, old_end; + unsigned long extent, old_next, new_next, old_end, new_end; struct mmu_notifier_range range; pmd_t *old_pmd, *new_pmd; old_end = old_addr + len; + new_end = new_addr + len; flush_cache_range(vma, old_addr, old_end); mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm, @@ -250,14 +251,11 @@ unsigned long move_page_tables(struct vm_area_struct *vma, for (; old_addr < old_end; old_addr += extent, new_addr += extent) { cond_resched(); - next = (old_addr + PMD_SIZE) & PMD_MASK; - /* even if next overflowed, extent below will be ok */ - extent = next - old_addr; - if (extent > old_end - old_addr) - extent = old_end - old_addr; - next = (new_addr + PMD_SIZE) & PMD_MASK; - if (extent > next - new_addr) - extent = next - new_addr; + + old_next = pmd_addr_end(old_addr, old_end); + new_next = pmd_addr_end(new_addr, new_end); + extent = min((old_next - old_addr), (new_next - new_addr)); + old_pmd = get_old_pmd(vma->vm_mm, old_addr); if (!old_pmd) continue;
The purpose of this code is to calculate the smaller extent in old and new range. Let's leverage pmd_addr_end() to do the calculation. Hope this would make the code easier to read. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> --- mm/mremap.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-)