diff --git a/media/mtp/MtpRequestPacket.cpp b/media/mtp/MtpRequestPacket.cpp
index 40b11b0..471967f 100644
--- a/media/mtp/MtpRequestPacket.cpp
+++ b/media/mtp/MtpRequestPacket.cpp
@@ -44,11 +44,12 @@
     }
 
     // request packet should have 12 byte header followed by 0 to 5 32-bit arguments
-    if (ret >= MTP_CONTAINER_HEADER_SIZE
-            && ret <= MTP_CONTAINER_HEADER_SIZE + 5 * sizeof(uint32_t)
-            && ((ret - MTP_CONTAINER_HEADER_SIZE) & 3) == 0) {
-        mPacketSize = ret;
-        mParameterCount = (ret - MTP_CONTAINER_HEADER_SIZE) / sizeof(uint32_t);
+    const size_t read_size = static_cast<size_t>(ret);
+    if (read_size >= MTP_CONTAINER_HEADER_SIZE
+            && read_size <= MTP_CONTAINER_HEADER_SIZE + 5 * sizeof(uint32_t)
+            && ((read_size - MTP_CONTAINER_HEADER_SIZE) & 3) == 0) {
+        mPacketSize = read_size;
+        mParameterCount = (read_size - MTP_CONTAINER_HEADER_SIZE) / sizeof(uint32_t);
     } else {
         ALOGE("Malformed MTP request packet");
         ret = -1;