switch /dev/zero and /dev/full to ->read_iter()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 917403f..524b707 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -622,53 +622,23 @@
return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
}
-static ssize_t read_zero(struct file *file, char __user *buf,
- size_t count, loff_t *ppos)
-{
- size_t written;
-
- if (!count)
- return 0;
-
- if (!access_ok(VERIFY_WRITE, buf, count))
- return -EFAULT;
-
- written = 0;
- while (count) {
- unsigned long unwritten;
- size_t chunk = count;
-
- if (chunk > PAGE_SIZE)
- chunk = PAGE_SIZE; /* Just for latency reasons */
- unwritten = __clear_user(buf, chunk);
- written += chunk - unwritten;
- if (unwritten)
- break;
- if (signal_pending(current))
- return written ? written : -ERESTARTSYS;
- buf += chunk;
- count -= chunk;
- cond_resched();
- }
- return written ? written : -EFAULT;
-}
-
-static ssize_t aio_read_zero(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos)
+static ssize_t read_iter_zero(struct kiocb *iocb, struct iov_iter *iter)
{
size_t written = 0;
- unsigned long i;
- ssize_t ret;
- for (i = 0; i < nr_segs; i++) {
- ret = read_zero(iocb->ki_filp, iov[i].iov_base, iov[i].iov_len,
- &pos);
- if (ret < 0)
- break;
- written += ret;
+ while (iov_iter_count(iter)) {
+ size_t chunk = iov_iter_count(iter), n;
+ if (chunk > PAGE_SIZE)
+ chunk = PAGE_SIZE; /* Just for latency reasons */
+ n = iov_iter_zero(chunk, iter);
+ if (!n && iov_iter_count(iter))
+ return written ? written : -EFAULT;
+ written += n;
+ if (signal_pending(current))
+ return written ? written : -ERESTARTSYS;
+ cond_resched();
}
-
- return written ? written : -EFAULT;
+ return written;
}
static int mmap_zero(struct file *file, struct vm_area_struct *vma)
@@ -738,7 +708,6 @@
#define zero_lseek null_lseek
#define full_lseek null_lseek
#define write_zero write_null
-#define read_full read_zero
#define aio_write_zero aio_write_null
#define open_mem open_port
#define open_kmem open_mem
@@ -783,9 +752,9 @@
static const struct file_operations zero_fops = {
.llseek = zero_lseek,
- .read = read_zero,
+ .read = new_sync_read,
.write = write_zero,
- .aio_read = aio_read_zero,
+ .read_iter = read_iter_zero,
.aio_write = aio_write_zero,
.mmap = mmap_zero,
};
@@ -802,7 +771,8 @@
static const struct file_operations full_fops = {
.llseek = full_lseek,
- .read = read_full,
+ .read = new_sync_read,
+ .read_iter = read_iter_zero,
.write = write_full,
};