diff options
| -rw-r--r-- | mm/process_vm_access.c | 91 |
1 files changed, 23 insertions, 68 deletions
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index 1e3c81103b2c..70ec3156f45a 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -51,13 +51,11 @@ static int process_vm_rw_pages(struct task_struct *task, ssize_t *bytes_copied) { int pages_pinned; - void *target_kaddr; int pgs_copied = 0; int j; int ret; ssize_t bytes_to_copy; ssize_t rc = 0; - const struct iovec *iov = iter->iov; *bytes_copied = 0; @@ -75,77 +73,34 @@ static int process_vm_rw_pages(struct task_struct *task, /* Do the copy for each page */ for (pgs_copied = 0; - (pgs_copied < nr_pages_to_copy) && iter->nr_segs; + (pgs_copied < nr_pages_to_copy) && iov_iter_count(iter); pgs_copied++) { - /* Make sure we have a non zero length iovec */ - while (iter->nr_segs && iov->iov_len == 0) { - iov++; - iter->nr_segs--; + struct page *page = process_pages[pgs_copied]; + bytes_to_copy = min_t(ssize_t, PAGE_SIZE - start_offset, len); + + if (vm_write) { + if (bytes_to_copy > iov_iter_count(iter)) + bytes_to_copy = iov_iter_count(iter); + ret = iov_iter_copy_from_user(page, + iter, start_offset, bytes_to_copy); + iov_iter_advance(iter, ret); + set_page_dirty_lock(page); + } else { + ret = copy_page_to_iter(page, start_offset, + bytes_to_copy, iter); } - if (!iter->nr_segs) - 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, - iov->iov_len - - iter->iov_offset); - - target_kaddr = kmap(process_pages[pgs_copied]) + start_offset; - - if (vm_write) - ret = copy_from_user(target_kaddr, - iov->iov_base - + iter->iov_offset, - bytes_to_copy); - else - ret = copy_to_user(iov->iov_base - + iter->iov_offset, - target_kaddr, bytes_to_copy); - kunmap(process_pages[pgs_copied]); - if (ret) { - *bytes_copied += bytes_to_copy - ret; - pgs_copied++; + *bytes_copied += ret; + len -= ret; + if (ret < bytes_to_copy && iov_iter_count(iter)) { rc = -EFAULT; - goto end; - } - *bytes_copied += bytes_to_copy; - iter->iov_offset += bytes_to_copy; - if (iter->iov_offset == iov->iov_len) { - /* - * Need to copy remaining part of page into the - * next iovec if there are any bytes left in page - */ - iter->nr_segs--; - iov++; - iter->iov_offset = 0; - start_offset = (start_offset + bytes_to_copy) - % PAGE_SIZE; - if (start_offset) - pgs_copied--; - } else { - start_offset = 0; + break; } + start_offset = 0; } end: - if (vm_write) { - for (j = 0; j < pages_pinned; j++) { - if (j < pgs_copied) - set_page_dirty_lock(process_pages[j]); - put_page(process_pages[j]); - } - } else { - for (j = 0; j < pages_pinned; j++) - put_page(process_pages[j]); - } - - iter->iov = iov; + for (j = 0; j < pages_pinned; j++) + put_page(process_pages[j]); return rc; } @@ -194,7 +149,7 @@ static int process_vm_rw_single_vec(unsigned long addr, return 0; nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1; - while ((nr_pages_copied < nr_pages) && iter->nr_segs) { + while ((nr_pages_copied < nr_pages) && iov_iter_count(iter)) { nr_pages_to_copy = min(nr_pages - nr_pages_copied, max_pages_per_loop); @@ -303,7 +258,7 @@ static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter, goto put_task_struct; } - for (i = 0; i < riovcnt && iter->nr_segs; i++) { + for (i = 0; i < riovcnt && iov_iter_count(iter); i++) { rc = process_vm_rw_single_vec( (unsigned long)rvec[i].iov_base, rvec[i].iov_len, iter, process_pages, mm, task, vm_write, |