From 352ea2365f251e1c26aa48d33c5d8c1a4abaa1c5 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Sun, 15 Mar 2020 16:10:37 +0100
Subject: [PATCH] Aesthetic changes in PR #6989.

---
 src/networking.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/networking.c b/src/networking.c
index 261c9b24a..c7dd2f23c 100644
--- a/src/networking.c
+++ b/src/networking.c
@@ -36,7 +36,7 @@
 
 static void setProtocolError(const char *errstr, client *c);
 int postponeClientRead(client *c);
-int process_while_blocked;
+int ProcessingEventsWhileBlocked = 0; /* See processEventsWhileBlocked(). */
 
 /* Return the size consumed from the allocator, for the specified SDS string,
  * including internal fragmentation. This function is used in order to compute
@@ -2739,7 +2739,12 @@ int clientsArePaused(void) {
 int processEventsWhileBlocked(void) {
     int iterations = 4; /* See the function top-comment. */
     int count = 0;
-    process_while_blocked = 1;
+
+    /* Note: when we are processing events while blocked (for instance during
+     * busy Lua scripts), we set a global flag. When such flag is set, we
+     * avoid handling the read part of clients using threaded I/O.
+     * See https://github.com/antirez/redis/issues/6988 for more info. */
+    ProcessingEventsWhileBlocked = 1;
     while (iterations--) {
         int events = 0;
         events += aeProcessEvents(server.el, AE_FILE_EVENTS|AE_DONT_WAIT);
@@ -2747,7 +2752,7 @@ int processEventsWhileBlocked(void) {
         if (!events) break;
         count += events;
     }
-    process_while_blocked = 0;
+    ProcessingEventsWhileBlocked = 0;
     return count;
 }
 
@@ -2819,7 +2824,6 @@ void *IOThreadMain(void *myid) {
 /* Initialize the data structures needed for threaded I/O. */
 void initThreadedIO(void) {
     io_threads_active = 0; /* We start with threads not active. */
-    process_while_blocked = 0; 
 
     /* Don't spawn any thread if the user selected a single thread:
      * we'll handle I/O directly from the main thread. */
@@ -2974,7 +2978,7 @@ int handleClientsWithPendingWritesUsingThreads(void) {
 int postponeClientRead(client *c) {
     if (io_threads_active &&
         server.io_threads_do_reads &&
-        !process_while_blocked &&
+        !ProcessingEventsWhileBlocked &&
         !(c->flags & (CLIENT_MASTER|CLIENT_SLAVE|CLIENT_PENDING_READ)))
     {
         c->flags |= CLIENT_PENDING_READ;