MTP: Don't attempt to read more than 16K at a time from the MTP driver DO NOT MERGE

This could happen sometimes if other operations increased the size of the
data packet buffer to > 16K

Change-Id: I10f85f0ce32df39f46b0a984361958c0a13f6800
Signed-off-by: Mike Lockwood <lockwood@google.com>

Author: Mike Lockwood

media/mtp/MtpDataPacket.cpp

@@ -25,10 +25,12 @@
 #include "MtpDataPacket.h"
 #include "MtpStringBuffer.h"
 
+#define MTP_BUFFER_SIZE 16384
+
 namespace android {
 
 MtpDataPacket::MtpDataPacket()
-    :   MtpPacket(16384),   // MAX_USBFS_BUFFER_SIZE
+    :   MtpPacket(MTP_BUFFER_SIZE),   // MAX_USBFS_BUFFER_SIZE
         mOffset(MTP_CONTAINER_HEADER_SIZE)
 {
 }
@@ -345,7 +347,7 @@ void MtpDataPacket::putString(const uint16_t* string) {
 
 #ifdef MTP_DEVICE 
 int MtpDataPacket::read(int fd) {
-    int ret = ::read(fd, mBuffer, mBufferSize);
+    int ret = ::read(fd, mBuffer, MTP_BUFFER_SIZE);
     if (ret < MTP_CONTAINER_HEADER_SIZE)
         return -1;
     mPacketSize = ret;