scsi: aacraid: Use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().

Link: https://lore.kernel.org/r/20200315094241.9086-2-tiwai@suse.de
Cc: "James E . J . Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: Adaptec OEM Raid Solutions <aacraid@microsemi.com>
Cc: linux-scsi@vger.kernel.org
Acked-by: Balsundar P <Balsundar.P@microchip.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/aacraid/linit.c

@@ -1287,20 +1287,21 @@ static ssize_t aac_show_flags(struct device *cdev,
 	if (nblank(dprintk(x)))
 		len = snprintf(buf, PAGE_SIZE, "dprintk\n");
 #ifdef AAC_DETAILED_STATUS_INFO
-	len += snprintf(buf + len, PAGE_SIZE - len,
+	len += scnprintf(buf + len, PAGE_SIZE - len,
-			"AAC_DETAILED_STATUS_INFO\n");
+			 "AAC_DETAILED_STATUS_INFO\n");
 #endif
 	if (dev->raw_io_interface && dev->raw_io_64)
-		len += snprintf(buf + len, PAGE_SIZE - len,
+		len += scnprintf(buf + len, PAGE_SIZE - len,
-				"SAI_READ_CAPACITY_16\n");
+				 "SAI_READ_CAPACITY_16\n");
 	if (dev->jbod)
-		len += snprintf(buf + len, PAGE_SIZE - len, "SUPPORTED_JBOD\n");
+		len += scnprintf(buf + len, PAGE_SIZE - len,
+				 "SUPPORTED_JBOD\n");
 	if (dev->supplement_adapter_info.supported_options2 &
 		AAC_OPTION_POWER_MANAGEMENT)
-		len += snprintf(buf + len, PAGE_SIZE - len,
+		len += scnprintf(buf + len, PAGE_SIZE - len,
-				"SUPPORTED_POWER_MANAGEMENT\n");
+				 "SUPPORTED_POWER_MANAGEMENT\n");
 	if (dev->msi)
-		len += snprintf(buf + len, PAGE_SIZE - len, "PCI_HAS_MSI\n");
+		len += scnprintf(buf + len, PAGE_SIZE - len, "PCI_HAS_MSI\n");
 	return len;
 }