switch /dev/zero and /dev/full to ->read_iter() (13ba33e8) · Commits · e / devices / android_kernel_fairphone_FP4

drivers/char/mem.c

+13 −43

Original line number	Original line	Diff line number	Diff line
	@@ -622,53 +622,23 @@ static ssize_t splice_write_null(struct pipe_inode_info pipe, struct file out,
	return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);		return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
	}		}

	static ssize_t read_zero(struct file file, char __user buf,		static ssize_t read_iter_zero(struct kiocb iocb, struct iov_iter iter)
	size_t count, loff_t *ppos)
	{		{
	size_t written;		size_t written = 0;

	if (!count)
	return 0;

	if (!access_ok(VERIFY_WRITE, buf, count))
	return -EFAULT;

	written = 0;
	while (count) {
	unsigned long unwritten;
	size_t chunk = count;

			while (iov_iter_count(iter)) {
			size_t chunk = iov_iter_count(iter), n;
	if (chunk > PAGE_SIZE)		if (chunk > PAGE_SIZE)
	chunk = PAGE_SIZE; /* Just for latency reasons */		chunk = PAGE_SIZE; /* Just for latency reasons */
	unwritten = __clear_user(buf, chunk);		n = iov_iter_zero(chunk, iter);
	written += chunk - unwritten;		if (!n && iov_iter_count(iter))
	if (unwritten)		return written ? written : -EFAULT;
	break;		written += n;
	if (signal_pending(current))		if (signal_pending(current))
	return written ? written : -ERESTARTSYS;		return written ? written : -ERESTARTSYS;
	buf += chunk;
	count -= chunk;
	cond_resched();		cond_resched();
	}		}
	return written ? written : -EFAULT;		return written;
	}

	static ssize_t aio_read_zero(struct kiocb iocb, const struct iovec iov,
	unsigned long nr_segs, loff_t pos)
	{
	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;
	}

	return written ? written : -EFAULT;
	}		}

	static int mmap_zero(struct file file, struct vm_area_struct vma)		static int mmap_zero(struct file file, struct vm_area_struct vma)
	@@ -738,7 +708,6 @@ static int open_port(struct inode inode, struct file filp)
	#define zero_lseek null_lseek		#define zero_lseek null_lseek
	#define full_lseek null_lseek		#define full_lseek null_lseek
	#define write_zero write_null		#define write_zero write_null
	#define read_full read_zero
	#define aio_write_zero aio_write_null		#define aio_write_zero aio_write_null
	#define open_mem open_port		#define open_mem open_port
	#define open_kmem open_mem		#define open_kmem open_mem
	@@ -783,9 +752,9 @@ static const struct file_operations port_fops = {

	static const struct file_operations zero_fops = {		static const struct file_operations zero_fops = {
	.llseek = zero_lseek,		.llseek = zero_lseek,
	.read = read_zero,		.read = new_sync_read,
	.write = write_zero,		.write = write_zero,
	.aio_read = aio_read_zero,		.read_iter = read_iter_zero,
	.aio_write = aio_write_zero,		.aio_write = aio_write_zero,
	.mmap = mmap_zero,		.mmap = mmap_zero,
	};		};
	@@ -802,7 +771,8 @@ static struct backing_dev_info zero_bdi = {

	static const struct file_operations full_fops = {		static const struct file_operations full_fops = {
	.llseek = full_lseek,		.llseek = full_lseek,
	.read = read_full,		.read = new_sync_read,
			.read_iter = read_iter_zero,
	.write = write_full,		.write = write_full,
	};		};