- if (from_user) {
- down(&tmp_buf_sem);
- while (1) {
- int c1;
- c = CIRC_SPACE_TO_END(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
- if (count < c)
- c = count;
- if (c <= 0)
- break;
-
- c -= copy_from_user(tmp_buf, buf, c);
- if (!c) {
- if (!ret)
- ret = -EFAULT;
- break;
- }
-
- local_irq_save(flags);
- {
- c1 = CIRC_SPACE_TO_END(info->xmit.head, info->xmit.tail,
- SERIAL_XMIT_SIZE);
- if (c1 < c)
- c = c1;
- memcpy(info->xmit.buf + info->xmit.head, tmp_buf, c);
- info->xmit.head = ((info->xmit.head + c) &
- (SERIAL_XMIT_SIZE-1));
- }
- local_irq_restore(flags);
-
- buf += c;
- count -= c;
- ret += c;
- }
- up(&tmp_buf_sem);
- } else {
- local_irq_save(flags);
- while (1) {
- c = CIRC_SPACE_TO_END(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
- if (count < c)
- c = count;
- if (c <= 0) {
- break;
- }
- memcpy(info->xmit.buf + info->xmit.head, buf, c);
- info->xmit.head = ((info->xmit.head + c) &
- (SERIAL_XMIT_SIZE-1));
- buf += c;
- count -= c;
- ret += c;