return written;
}
+static ssize_t read_zero(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ size_t cleared = 0;
+
+ while (count) {
+ size_t chunk = min_t(size_t, count, PAGE_SIZE);
+
+ if (clear_user(buf + cleared, chunk))
+ return cleared ? cleared : -EFAULT;
+ cleared += chunk;
+ count -= chunk;
+
+ if (signal_pending(current))
+ return cleared ? cleared : -ERESTARTSYS;
+ cond_resched();
+ }
+
+ return cleared;
+}
+
static int mmap_zero(struct file *file, struct vm_area_struct *vma)
{
#ifndef CONFIG_MMU
.llseek = zero_lseek,
.write = write_zero,
.read_iter = read_iter_zero,
+ .read = read_zero,
.write_iter = write_iter_zero,
.mmap = mmap_zero,
.get_unmapped_area = get_unmapped_area_zero,