process_vm_rw_pages(): pass accurate amount of bytes
... makes passing the amount of pages unnecessary
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index c2a1916..83252d7 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -41,20 +41,22 @@
*/
static int process_vm_rw_pages(struct page **pages,
unsigned offset,
- unsigned long len,
+ size_t len,
struct iov_iter *iter,
int vm_write,
- unsigned int nr_pages_to_copy,
ssize_t *bytes_copied)
{
*bytes_copied = 0;
/* Do the copy for each page */
- while (iov_iter_count(iter) && nr_pages_to_copy--) {
+ while (iov_iter_count(iter) && len) {
struct page *page = *pages++;
- size_t copy = min_t(ssize_t, PAGE_SIZE - offset, len);
+ size_t copy = PAGE_SIZE - offset;
size_t copied;
+ if (copy > len)
+ copy = len;
+
if (vm_write) {
if (copy > iov_iter_count(iter))
copy = iov_iter_count(iter);
@@ -121,6 +123,7 @@
while ((nr_pages_copied < nr_pages) && iov_iter_count(iter)) {
int nr_pages_to_copy;
int pages_pinned;
+ size_t n;
nr_pages_to_copy = min(nr_pages - nr_pages_copied,
max_pages_per_loop);
@@ -134,18 +137,21 @@
if (pages_pinned <= 0)
return -EFAULT;
+ n = pages_pinned * PAGE_SIZE - start_offset;
+ if (n > len)
+ n = len;
+
rc = process_vm_rw_pages(process_pages,
- start_offset, len, iter,
- vm_write, pages_pinned,
+ start_offset, n, iter,
+ vm_write,
&bytes_copied_loop);
+ len -= n;
start_offset = 0;
*bytes_copied += bytes_copied_loop;
- len -= bytes_copied_loop;
nr_pages_copied += pages_pinned;
pa += pages_pinned * PAGE_SIZE;
while (pages_pinned)
put_page(process_pages[--pages_pinned]);
-
if (rc < 0)
break;
}