commit 8efadf70e10fcc12e227e98e838e7544fc26256c
author Hridya Valsaraju <hridya@google.com> Mon Apr 15 10:27:38 2019 -0700
committer Hridya Valsaraju <hridya@google.com> Mon Apr 15 10:36:42 2019 -0700
tree c9e9cd65b3cce361efac7472d877e2cd49e08bf2
parent 21aa749ec71e44bdde61f8d6173a18350d1344e5

Handle failed usb/reads and writes correctly

Currently if the device is unplugged from host,
there is a lot of log spamming since fastbootd
does not not recognize that the device has been
disconnected and keeps trying to read/write to the
device.

2856 printk messages dropped ** [  169.941904] c7    579 fastbootd: aio: got error event on
read total bufs 1: No such devie
** 2960 printk messages dropped ** [  169.953328] c7    579 fastbootd: Fastboot command:
** 2074 printk messages dropped ** [  169.961355] c7    579 fastbootd: aio: got error event
on read total bufs 1: No such devie

Bug: 121333158
Test: unplug device and check for log spam multiple times

Change-Id: I1d4c6f48f34e313c5ebce23d62a4fe6a6373f94f

fastboot/device/usb_client.cpp

diff --git a/fastboot/device/usb_client.cpp b/fastboot/device/usb_client.cpp
index fb51a90..511bd5c 100644
--- a/fastboot/device/usb_client.cpp
+++ b/fastboot/device/usb_client.cpp
@@ -257,7 +257,7 @@
         auto bytes_to_read = std::min(len - bytes_read_total, kFbFfsNumBufs * kFbFfsBufSize);
         auto bytes_read_now = handle_->read(handle_.get(), char_data, bytes_to_read);
         if (bytes_read_now < 0) {
-            return bytes_read_total;
+            return bytes_read_total == 0 ? -1 : bytes_read_total;
         }
         bytes_read_total += bytes_read_now;
         char_data += bytes_read_now;
@@ -278,7 +278,7 @@
         auto bytes_to_write = std::min(len - bytes_written_total, kFbFfsNumBufs * kFbFfsBufSize);
         auto bytes_written_now = handle_->write(handle_.get(), data, bytes_to_write);
         if (bytes_written_now < 0) {
-            return bytes_written_total;
+            return bytes_written_total == 0 ? -1 : bytes_written_total;
         }
         bytes_written_total += bytes_written_now;
         char_data += bytes_written_now;