ASoC: Fix theoretical buffer overflow by snprintf()

Merge series from Takashi Iwai <tiwai@suse.de>:

This is a patch series to paper over the theoretical buffer overflow
that might be caused by snprintf().  snprintf() is notorious for its
behavior and the usage of a safer version, scnprintf(), is
recommended.

sound/soc/intel/avs/pcm.c

@@ -636,8 +636,8 @@ static ssize_t topology_name_read(struct file *file, char __user *user_buf, size
 	char buf[64];
 	size_t len;
 
-	len = snprintf(buf, sizeof(buf), "%s/%s\n", component->driver->topology_name_prefix,
-		       mach->tplg_filename);
+	len = scnprintf(buf, sizeof(buf), "%s/%s\n", component->driver->topology_name_prefix,
+			mach->tplg_filename);
 
 	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 }

sound/soc/sof/debug.c

@@ -252,9 +252,9 @@ static int memory_info_update(struct snd_sof_dev *sdev, char *buf, size_t buff_s
 	}
 
 	for (i = 0, len = 0; i < reply->num_elems; i++) {
-		ret = snprintf(buf + len, buff_size - len, "zone %d.%d used %#8x free %#8x\n",
-			       reply->elems[i].zone, reply->elems[i].id,
-			       reply->elems[i].used, reply->elems[i].free);
+		ret = scnprintf(buf + len, buff_size - len, "zone %d.%d used %#8x free %#8x\n",
+				reply->elems[i].zone, reply->elems[i].id,
+				reply->elems[i].used, reply->elems[i].free);
 		if (ret < 0)
 			goto error;
 		len += ret;

sound/soc/sof/intel/hda.c

@@ -574,7 +574,7 @@ static void hda_dsp_dump_ext_rom_status(struct snd_sof_dev *sdev, const char *le
 	chip = get_chip_info(sdev->pdata);
 	for (i = 0; i < HDA_EXT_ROM_STATUS_SIZE; i++) {
 		value = snd_sof_dsp_read(sdev, HDA_DSP_BAR, chip->rom_status_reg + i * 0x4);
-		len += snprintf(msg + len, sizeof(msg) - len, " 0x%x", value);
+		len += scnprintf(msg + len, sizeof(msg) - len, " 0x%x", value);
 	}
 
 	dev_printk(level, sdev->dev, "extended rom status: %s", msg);