diff options
Diffstat (limited to '')
| -rw-r--r-- | mm/migrate.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 4389696fba0e..5d1839a9148d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1324,8 +1324,19 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, goto put_anon; if (page_mapped(hpage)) { + struct address_space *mapping = page_mapping(hpage); + + /* + * try_to_unmap could potentially call huge_pmd_unshare. + * Because of this, take semaphore in write mode here and + * set TTU_RMAP_LOCKED to let lower levels know we have + * taken the lock. + */ + i_mmap_lock_write(mapping); try_to_unmap(hpage, - TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); + TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS| + TTU_RMAP_LOCKED); + i_mmap_unlock_write(mapping); page_was_mapped = 1; } |