From: Pavel Charvat <pchar@ucw.cz>
Date: Sun, 11 Feb 2018 16:32:48 +0000 (+0100)
Subject: Main recio: Avoid calling of read_handler() with zero available bytes.
X-Git-Tag: v6.5.9~5
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=555f79c1d4e8279370f365bcb9bc4a5e136e0e9e;p=libucw.git

Main recio: Avoid calling of read_handler() with zero available bytes.

The problem was in the deferred hook. Also changed it's return value,
hooks like this should always return HOOK_IDLE and not slower HOOK_RETRY.
---

diff --git a/ucw/main-rec.c b/ucw/main-rec.c
index 7279d99d..f13758e3 100644
--- a/ucw/main-rec.c
+++ b/ucw/main-rec.c
@@ -77,11 +77,13 @@ static int
 rec_io_process_read_buf(struct main_rec_io *rio)
 {
   uint got;
+  ASSERT(rio->read_prev_avail < rio->read_avail);
   while (rio->read_running && (got = rio->read_handler(rio)))
     {
       DBG("RIO READ: Ate %u bytes", got);
       if (got == ~0U)
 	return HOOK_IDLE;
+      ASSERT(got <= rio->read_avail);
       rio->read_rec_start += got;
       rio->read_avail -= got;
       rio->read_prev_avail = 0;
@@ -181,7 +183,10 @@ rec_io_deferred_start_read(struct main_hook *ho)
   rio->read_running = 1;
 
   rio->read_prev_avail = 0;
-  return rec_io_process_read_buf(rio);
+  if (rio->read_avail)
+    rec_io_process_read_buf(rio);
+
+  return HOOK_IDLE;
 }
 
 static void