diff options
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index b3f00b616b81..84b12624ceb0 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -3184,10 +3184,16 @@ static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) * mapping->flags avoid to take the same lock twice, if more than one * vma in this mm is backed by the same anon_vma or address_space. * - * We can take all the locks in random order because the VM code - * taking i_mmap_rwsem or anon_vma->rwsem outside the mmap_sem never - * takes more than one of them in a row. Secondly we're protected - * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. + * We take locks in following order, accordingly to comment at beginning + * of mm/rmap.c: + * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for + * hugetlb mapping); + * - all i_mmap_rwsem locks; + * - all anon_vma->rwseml + * + * We can take all locks within these types randomly because the VM code + * doesn't nest them and we protected from parallel mm_take_all_locks() by + * mm_all_locks_mutex. * * mm_take_all_locks() and mm_drop_all_locks are expensive operations * that may have to take thousand of locks. @@ -3206,7 +3212,16 @@ int mm_take_all_locks(struct mm_struct *mm) for (vma = mm->mmap; vma; vma = vma->vm_next) { if (signal_pending(current)) goto out_unlock; - if (vma->vm_file && vma->vm_file->f_mapping) + if (vma->vm_file && vma->vm_file->f_mapping && + is_vm_hugetlb_page(vma)) + vm_lock_mapping(mm, vma->vm_file->f_mapping); + } + + for (vma = mm->mmap; vma; vma = vma->vm_next) { + if (signal_pending(current)) + goto out_unlock; + if (vma->vm_file && vma->vm_file->f_mapping && + !is_vm_hugetlb_page(vma)) vm_lock_mapping(mm, vma->vm_file->f_mapping); } |