crypto: hisilicon - allow smaller reads in debugfs

Originally this code rejected any read less than 256 bytes. There
is no need for this artificial limit. We should just use the normal
helper functions to read a string from the kernel.

Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/hisilicon/qm.c

···
 	char buf[QM_DBG_READ_LEN];
 	int len;
 
-	if (*pos)
-		return 0;
+	len = scnprintf(buf, QM_DBG_READ_LEN, "%s\n",
+			"Please echo help to cmd to get help information");
 
-	if (count < QM_DBG_READ_LEN)
-		return -ENOSPC;
-
-	len = snprintf(buf, QM_DBG_READ_LEN, "%s\n",
-		       "Please echo help to cmd to get help information");
-
-	if (copy_to_user(buffer, buf, len))
-		return -EFAULT;
-
-	return (*pos = len);
+	return simple_read_from_buffer(buffer, count, pos, buf, len);
 }
 
 static void *qm_ctx_alloc(struct hisi_qm *qm, size_t ctx_size,
···
 {
 	struct hisi_qm *qm = filp->private_data;
 	char buf[QM_DBG_READ_LEN];
-	int val, cp_len, len;
-
-	if (*pos)
-		return 0;
-
-	if (count < QM_DBG_READ_LEN)
-		return -ENOSPC;
+	int val, len;
 
 	val = atomic_read(&qm->status.flags);
-	len = snprintf(buf, QM_DBG_READ_LEN, "%s\n", qm_s[val]);
-	if (!len)
-		return -EFAULT;
+	len = scnprintf(buf, QM_DBG_READ_LEN, "%s\n", qm_s[val]);
 
-	cp_len = copy_to_user(buffer, buf, len);
-	if (cp_len)
-		return -EFAULT;
-
-	return (*pos = len);
+	return simple_read_from_buffer(buffer, count, pos, buf, len);
 }
 
 static const struct file_operations qm_status_fops = {