mm: mremap: move_ptes() use pte_offset_map_rw_nolock()

In move_ptes(), we may modify the new_pte after acquiring the new_ptl, so
convert it to using pte_offset_map_rw_nolock().  Now new_pte is none, so
hpage_collapse_scan_file() path can not find this by traversing
file->f_mapping, so there is no concurrency with retract_page_tables(). 
In addition, we already hold the exclusive mmap_lock, so this new_pte page
is stable, so there is no need to get pmdval and do pmd_same() check.

Link: https://lkml.kernel.org/r/9d582a09dbcf12e562ac5fe0ba05e9248a58f5e0.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <[email protected]>
Reviewed-by: Muchun Song <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Mike Rapoport (Microsoft) <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Vishal Moola (Oracle) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions