- for (pgs_copied = 0;
- (pgs_copied < nr_pages_to_copy) && (*lvec_current < lvec_cnt);
- pgs_copied++) {
- /* Make sure we have a non zero length iovec */
- while (*lvec_current < lvec_cnt
- && lvec[*lvec_current].iov_len == 0)
- (*lvec_current)++;
- if (*lvec_current == lvec_cnt)
- break;
-
- /*
- * Will copy smallest of:
- * - bytes remaining in page
- * - bytes remaining in destination iovec
- */
- bytes_to_copy = min_t(ssize_t, PAGE_SIZE - start_offset,
- len - *bytes_copied);
- bytes_to_copy = min_t(ssize_t, bytes_to_copy,
- lvec[*lvec_current].iov_len
- - *lvec_offset);
-
- target_kaddr = kmap(process_pages[pgs_copied]) + start_offset;
-
- if (vm_write)
- ret = copy_from_user(target_kaddr,
- lvec[*lvec_current].iov_base
- + *lvec_offset,
- bytes_to_copy);
- else
- ret = copy_to_user(lvec[*lvec_current].iov_base
- + *lvec_offset,
- target_kaddr, bytes_to_copy);
- kunmap(process_pages[pgs_copied]);
- if (ret) {
- *bytes_copied += bytes_to_copy - ret;
- pgs_copied++;
- rc = -EFAULT;
- goto end;
- }
- *bytes_copied += bytes_to_copy;
- *lvec_offset += bytes_to_copy;
- if (*lvec_offset == lvec[*lvec_current].iov_len) {
- /*
- * Need to copy remaining part of page into the
- * next iovec if there are any bytes left in page
- */
- (*lvec_current)++;
- *lvec_offset = 0;
- start_offset = (start_offset + bytes_to_copy)
- % PAGE_SIZE;
- if (start_offset)
- pgs_copied--;
+ while (len && iov_iter_count(iter)) {
+ struct page *page = *pages++;
+ 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);
+ copied = iov_iter_copy_from_user(page, iter,
+ offset, copy);
+ iov_iter_advance(iter, copied);
+ set_page_dirty_lock(page);