Re: [RFC v7 PATCH 1/4] mm: refactor do_munmap() to extract the common part
On 8/10/18 10:41 AM, Matthew Wilcox wrote:
On Fri, Aug 10, 2018 at 07:36:00AM +0800, Yang Shi wrote:
+static inline bool addr_ok(unsigned long start, size_t len)
Maybe munmap_range_ok()? Otherwise some of the conditions here don't make
sense for such a generic sounding function.
I don't know. I think the argument is about munmap_ prefix should be used.
{
- unsigned long end;
- struct vm_area_struct *vma, *prev, *last;
-
if ((offset_in_page(start)) || start > TASK_SIZE || len >
TASK_SIZE-start)
- return -EINVAL;
+ return false;
- len = PAGE_ALIGN(len);
- if (len == 0)
- return -EINVAL;
+ if (PAGE_ALIGN(len) == 0)
+ return false;
+
+ return true;
+}
+
+/*
+ * munmap_lookup_vma: find the first overlap vma and split overlap vmas.
+ * @mm: mm_struct
+ * @start: start address
+ * @end: end address
+ *
+ * returns the pointer to vma, NULL or err ptr when spilt_vma returns error.
kernel-doc prefers:
* Return: %NULL if no VMA overlaps this range. An ERR_PTR if an
* overlapping VMA could not be split. Otherwise a pointer to the first
* VMA which overlaps the range.
Ok, will fix it.
+ */
+static struct vm_area_struct *munmap_lookup_vma(struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ struct vm_area_struct *vma, *prev, *last;
/* Find the first overlapping VMA */
vma = find_vma(mm, start);
if (!vma)
- return 0;
- prev = vma->vm_prev;
- /* we have start < vma->vm_end */
+ return NULL;
+ /* we have start < vma->vm_end */
Can you remove the duplicate spaces here?
Sure
Thanks,
Yang
Re: [RFC v7 PATCH 1/4] mm: refactor do_munmap() to extract the common part
On Fri, Aug 10, 2018 at 07:36:00AM +0800, Yang Shi wrote:
> +static inline bool addr_ok(unsigned long start, size_t len)
Maybe munmap_range_ok()? Otherwise some of the conditions here don't make
sense for such a generic sounding function.
> {
> - unsigned long end;
> - struct vm_area_struct *vma, *prev, *last;
> -
> if ((offset_in_page(start)) || start > TASK_SIZE || len >
> TASK_SIZE-start)
> - return -EINVAL;
> + return false;
>
> - len = PAGE_ALIGN(len);
> - if (len == 0)
> - return -EINVAL;
> + if (PAGE_ALIGN(len) == 0)
> + return false;
> +
> + return true;
> +}
> +
> +/*
> + * munmap_lookup_vma: find the first overlap vma and split overlap vmas.
> + * @mm: mm_struct
> + * @start: start address
> + * @end: end address
> + *
> + * returns the pointer to vma, NULL or err ptr when spilt_vma returns error.
kernel-doc prefers:
* Return: %NULL if no VMA overlaps this range. An ERR_PTR if an
* overlapping VMA could not be split. Otherwise a pointer to the first
* VMA which overlaps the range.
> + */
> +static struct vm_area_struct *munmap_lookup_vma(struct mm_struct *mm,
> + unsigned long start, unsigned long end)
> +{
> + struct vm_area_struct *vma, *prev, *last;
>
> /* Find the first overlapping VMA */
> vma = find_vma(mm, start);
> if (!vma)
> - return 0;
> - prev = vma->vm_prev;
> - /* we have start < vma->vm_end */
> + return NULL;
>
> + /* we have start < vma->vm_end */
Can you remove the duplicate spaces here?
Re: [RFC v7 PATCH 1/4] mm: refactor do_munmap() to extract the common part
On 08/10/2018 01:36 AM, Yang Shi wrote:
> Introduces three new helper functions:
> * addr_ok()
> * munmap_lookup_vma()
> * munlock_vmas()
>
> They will be used by do_munmap() and the new do_munmap with zapping
> large mapping early in the later patch.
>
> There is no functional change, just code refactor.
>
> Reviewed-by: Laurent Dufour
> Signed-off-by: Yang Shi
Acked-by: Vlastimil Babka
Small nit below.
> @@ -2764,13 +2812,7 @@ int do_munmap(struct mm_struct *mm, unsigned long
> start, size_t len,
>*/
> if (mm->locked_vm) {
> struct vm_area_struct *tmp = vma;
> - while (tmp && tmp->vm_start < end) {
> - if (tmp->vm_flags & VM_LOCKED) {
> - mm->locked_vm -= vma_pages(tmp);
> - munlock_vma_pages_all(tmp);
> - }
> - tmp = tmp->vm_next;
> - }
> + munlock_vmas(tmp, end);
No need for 'tmp' here.
> }
>
> /*
>
