diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/mm/memory.c b/mm/memory.c index 7e131325bdf8..4d0a543f3bb3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2399,7 +2399,10 @@ EXPORT_SYMBOL(unmap_mapping_range); /* * We enter with non-exclusive mmap_sem (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. - * We return with mmap_sem still held, but pte unmapped and unlocked. + * We return with pte unmapped and unlocked. + * + * We return with the mmap_sem locked or unlocked in the same cases + * as does filemap_fault(). */ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *page_table, pmd_t *pmd, @@ -2688,6 +2691,11 @@ oom: return VM_FAULT_OOM; } +/* + * The mmap_sem must have been held on entry, and may have been + * released depending on flags and vma->vm_ops->fault() return value. + * See filemap_fault() and __lock_page_retry(). + */ static int __do_fault(struct vm_area_struct *vma, unsigned long address, pgoff_t pgoff, unsigned int flags, struct page **page) { @@ -3016,6 +3024,12 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma, return ret; } +/* + * We enter with non-exclusive mmap_sem (to exclude vma changes, + * but allow concurrent faults). + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). + */ static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *page_table, pmd_t *pmd, unsigned int flags, pte_t orig_pte) @@ -3040,7 +3054,9 @@ static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, * * We enter with non-exclusive mmap_sem (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. - * We return with mmap_sem still held, but pte unmapped and unlocked. + * We return with pte unmapped and unlocked. + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). */ static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *page_table, pmd_t *pmd, @@ -3172,7 +3188,10 @@ out: * * We enter with non-exclusive mmap_sem (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. - * We return with mmap_sem still held, but pte unmapped and unlocked. + * We return with pte unmapped and unlocked. + * + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). */ static int handle_pte_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, @@ -3232,6 +3251,9 @@ unlock: /* * By the time we get here, we already hold the mm semaphore + * + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). */ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, unsigned int flags) @@ -3313,6 +3335,12 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, return handle_pte_fault(mm, vma, address, pte, pmd, flags); } +/* + * By the time we get here, we already hold the mm semaphore + * + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). + */ int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, unsigned int flags) { |