process_vm_access: take get_user_pages/put_pages one level up
... and trim the fuck out of process_vm_rw_pages() argument list. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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240f3905f5
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70eca12d80
1 changed files with 39 additions and 58 deletions
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@ -39,69 +39,39 @@
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* @bytes_copied: returns number of bytes successfully copied
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* Returns 0 on success, error code otherwise
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*/
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static int process_vm_rw_pages(struct task_struct *task,
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struct mm_struct *mm,
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struct page **process_pages,
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unsigned long pa,
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unsigned long start_offset,
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static int process_vm_rw_pages(struct page **pages,
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unsigned offset,
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unsigned long len,
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struct iov_iter *iter,
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int vm_write,
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unsigned int nr_pages_to_copy,
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ssize_t *bytes_copied)
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{
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int pages_pinned;
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int pgs_copied = 0;
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int j;
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int ret;
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ssize_t bytes_to_copy;
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ssize_t rc = 0;
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*bytes_copied = 0;
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/* Get the pages we're interested in */
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down_read(&mm->mmap_sem);
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pages_pinned = get_user_pages(task, mm, pa,
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nr_pages_to_copy,
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vm_write, 0, process_pages, NULL);
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up_read(&mm->mmap_sem);
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if (pages_pinned != nr_pages_to_copy) {
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rc = -EFAULT;
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goto end;
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}
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/* Do the copy for each page */
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for (pgs_copied = 0;
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(pgs_copied < nr_pages_to_copy) && iov_iter_count(iter);
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pgs_copied++) {
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struct page *page = process_pages[pgs_copied];
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bytes_to_copy = min_t(ssize_t, PAGE_SIZE - start_offset, len);
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while (iov_iter_count(iter) && nr_pages_to_copy--) {
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struct page *page = *pages++;
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size_t copy = min_t(ssize_t, PAGE_SIZE - offset, len);
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size_t copied;
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if (vm_write) {
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if (bytes_to_copy > iov_iter_count(iter))
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bytes_to_copy = iov_iter_count(iter);
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ret = iov_iter_copy_from_user(page,
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iter, start_offset, bytes_to_copy);
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iov_iter_advance(iter, ret);
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if (copy > iov_iter_count(iter))
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copy = iov_iter_count(iter);
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copied = iov_iter_copy_from_user(page, iter,
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offset, copy);
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iov_iter_advance(iter, copied);
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set_page_dirty_lock(page);
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} else {
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ret = copy_page_to_iter(page, start_offset,
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bytes_to_copy, iter);
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copied = copy_page_to_iter(page, offset, copy, iter);
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}
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*bytes_copied += ret;
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len -= ret;
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if (ret < bytes_to_copy && iov_iter_count(iter)) {
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rc = -EFAULT;
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break;
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}
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start_offset = 0;
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*bytes_copied += copied;
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len -= copied;
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if (copied < copy && iov_iter_count(iter))
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return -EFAULT;
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offset = 0;
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}
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end:
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for (j = 0; j < pages_pinned; j++)
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put_page(process_pages[j]);
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return rc;
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return 0;
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}
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/* Maximum number of pages kmalloc'd to hold struct page's during copy */
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@ -138,7 +108,6 @@ static int process_vm_rw_single_vec(unsigned long addr,
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ssize_t bytes_copied_loop;
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ssize_t rc = 0;
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unsigned long nr_pages_copied = 0;
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unsigned long nr_pages_to_copy;
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unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
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/ sizeof(struct pages *);
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@ -150,23 +119,35 @@ static int process_vm_rw_single_vec(unsigned long addr,
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nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
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while ((nr_pages_copied < nr_pages) && iov_iter_count(iter)) {
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int nr_pages_to_copy;
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int pages_pinned;
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nr_pages_to_copy = min(nr_pages - nr_pages_copied,
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max_pages_per_loop);
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rc = process_vm_rw_pages(task, mm, process_pages, pa,
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/* Get the pages we're interested in */
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down_read(&mm->mmap_sem);
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pages_pinned = get_user_pages(task, mm, pa,
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nr_pages_to_copy,
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vm_write, 0, process_pages, NULL);
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up_read(&mm->mmap_sem);
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if (pages_pinned <= 0)
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return -EFAULT;
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rc = process_vm_rw_pages(process_pages,
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start_offset, len, iter,
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vm_write, nr_pages_to_copy,
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vm_write, pages_pinned,
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&bytes_copied_loop);
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start_offset = 0;
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*bytes_copied += bytes_copied_loop;
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len -= bytes_copied_loop;
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nr_pages_copied += pages_pinned;
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pa += pages_pinned * PAGE_SIZE;
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while (pages_pinned)
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put_page(process_pages[--pages_pinned]);
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if (rc < 0) {
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return rc;
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} else {
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len -= bytes_copied_loop;
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nr_pages_copied += nr_pages_to_copy;
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pa += nr_pages_to_copy * PAGE_SIZE;
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}
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if (rc < 0)
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break;
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}
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return rc;
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