From 0b19540dee9d0eee56f87705eea771b13800290f Mon Sep 17 00:00:00 2001
From: Josh Gao <jmgao@google.com>
Date: Wed, 16 Dec 2015 11:00:08 -0800
Subject: [PATCH] adb: split up reads longer than 16k.

Reads from functionfs allocate contiguous buffers in the kernel, causing
long ones to sometimes fail because of memory fragmentation.

Bug: http://b/26206622
Change-Id: Id40753d6f29b37b5ca97c3e2fa3921f52b4242de
---
 adb/usb_linux_client.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/adb/usb_linux_client.cpp b/adb/usb_linux_client.cpp
index ceed8facf..151c0aa11 100644
--- a/adb/usb_linux_client.cpp
+++ b/adb/usb_linux_client.cpp
@@ -481,7 +481,8 @@ static int usb_ffs_read(usb_handle* h, void* data, int len) {
 
     char* buf = static_cast<char*>(data);
     while (len > 0) {
-        int n = adb_read(h->bulk_out, buf, len);
+        int read_len = (len > 16384) ? 16384 : len;
+        int n = adb_read(h->bulk_out, buf, read_len);
         if (n < 0) {
             D("ERROR: fd = %d, n = %d: %s", h->bulk_out, n, strerror(errno));
             return -1;