diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/mm/memory.c b/mm/memory.c index c48f8df6e502..4a42a74a2240 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1171,6 +1171,15 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 0, src_vma, src_mm, addr, end); mmu_notifier_invalidate_range_start(&range); + /* + * Disabling preemption is not needed for the write side, as + * the read side doesn't spin, but goes to the mmap_lock. + * + * Use the raw variant of the seqcount_t write API to avoid + * lockdep complaining about preemptibility. + */ + mmap_assert_write_locked(src_mm); + raw_write_seqcount_begin(&src_mm->write_protect_seq); } ret = 0; @@ -1187,8 +1196,10 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) } } while (dst_pgd++, src_pgd++, addr = next, addr != end); - if (is_cow) + if (is_cow) { + raw_write_seqcount_end(&src_mm->write_protect_seq); mmu_notifier_invalidate_range_end(&range); + } return ret; } @@ -4874,11 +4885,10 @@ EXPORT_SYMBOL_GPL(generic_access_phys); #endif /* - * Access another process' address space as given in mm. If non-NULL, use the - * given task for page fault accounting. + * Access another process' address space as given in mm. */ -int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, unsigned int gup_flags) +int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, + int len, unsigned int gup_flags) { struct vm_area_struct *vma; void *old_buf = buf; @@ -4955,7 +4965,7 @@ int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, unsigned int gup_flags) { - return __access_remote_vm(NULL, mm, addr, buf, len, gup_flags); + return __access_remote_vm(mm, addr, buf, len, gup_flags); } /* @@ -4973,7 +4983,7 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, if (!mm) return 0; - ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags); + ret = __access_remote_vm(mm, addr, buf, len, gup_flags); mmput(mm); |