From 6e9a327504e6aa2488b736fd5592525278a0916f Mon Sep 17 00:00:00 2001
From: Jerry Zhang <zhangjerry@google.com>
Date: Mon, 19 Mar 2018 17:54:39 -0700
Subject: [PATCH] adb: Retry io in case of interrupt

io_submit sleeps waiting for the gadget
to be enabled. Currently if that sleep
is interrupted it will shut down adb,
causing it to have to start back up again.

Rather than return EINTR if interrupted,
io_submit actually completes and the EINTR
is found later when looking through events.
Since an io that is interrupted will be
small anyway, add a loop to retry small ios.

Also upgrade aio logs in accordance with
their importance.

Fixes: 75981904
Test: adb works, logs show successful interrupt handling
Change-Id: I35973fce130ee849ce59fef80d15b65afb816ba4
---
 adb/daemon/usb.cpp | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/adb/daemon/usb.cpp b/adb/daemon/usb.cpp
index c2e933782..78693248d 100644
--- a/adb/daemon/usb.cpp
+++ b/adb/daemon/usb.cpp
@@ -437,23 +437,29 @@ static int usb_ffs_do_aio(usb_handle* h, const void* data, int len, bool read) {
         num_bufs += 1;
     }
 
-    if (io_submit(aiob->ctx, num_bufs, aiob->iocbs.data()) < num_bufs) {
-        D("[ aio: got error submitting %s (%d) ]", read ? "read" : "write", errno);
-        return -1;
-    }
-    if (TEMP_FAILURE_RETRY(
-            io_getevents(aiob->ctx, num_bufs, num_bufs, aiob->events.data(), nullptr)) < num_bufs) {
-        D("[ aio: got error waiting %s (%d) ]", read ? "read" : "write", errno);
-        return -1;
-    }
-    for (int i = 0; i < num_bufs; i++) {
-        if (aiob->events[i].res < 0) {
-            errno = aiob->events[i].res;
-            D("[ aio: got error event on %s (%d) ]", read ? "read" : "write", errno);
+    while (true) {
+        if (TEMP_FAILURE_RETRY(io_submit(aiob->ctx, num_bufs, aiob->iocbs.data())) < num_bufs) {
+            PLOG(ERROR) << "aio: got error submitting " << (read ? "read" : "write");
             return -1;
         }
+        if (TEMP_FAILURE_RETRY(io_getevents(aiob->ctx, num_bufs, num_bufs, aiob->events.data(),
+                                            nullptr)) < num_bufs) {
+            PLOG(ERROR) << "aio: got error waiting " << (read ? "read" : "write");
+            return -1;
+        }
+        if (num_bufs == 1 && aiob->events[0].res == -EINTR) {
+            continue;
+        }
+        for (int i = 0; i < num_bufs; i++) {
+            if (aiob->events[i].res < 0) {
+                errno = -aiob->events[i].res;
+                PLOG(ERROR) << "aio: got error event on " << (read ? "read" : "write")
+                            << " total bufs " << num_bufs;
+                return -1;
+            }
+        }
+        return 0;
     }
-    return 0;
 }
 
 static int usb_ffs_aio_read(usb_handle* h, void* data, int len) {