From 45f99bbd0ab71559a2ce7631c1e8fe409e52b70c Mon Sep 17 00:00:00 2001
From: leitner <leitner>
Date: Sat, 24 Apr 2021 11:39:18 +0000
Subject: [PATCH] in io_eagain, make sure the kernel knows we wanted to write
 to the descriptor in case we optimized the syscall away previously in
 iob_send leave loop if we got a partial write

---
 io/io_eagain.c       | 2 ++
 io/io_eagain_write.c | 2 ++
 io/iob_send.c        | 5 +++--
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/io/io_eagain.c b/io/io_eagain.c
index a5a5a27..d1bc91e 100644
--- a/io/io_eagain.c
+++ b/io/io_eagain.c
@@ -5,6 +5,8 @@ void io_eagain(int64 d) {
   if (e) {
     if (e->wantread) e->canread=0;
     if (e->wantwrite) e->canwrite=0;
+    if (e->wantwrite && !e->kernelwantwrite)
+      io_wantwrite(d);
 #if defined(HAVE_SIGIO)
     if (d==alt_curread) {
 #if 0
diff --git a/io/io_eagain_write.c b/io/io_eagain_write.c
index bf973a5..8e01f5a 100644
--- a/io/io_eagain_write.c
+++ b/io/io_eagain_write.c
@@ -4,6 +4,8 @@ void io_eagain_write(int64 d) {
   io_entry* e=iarray_get(&io_fds,d);
   if (e) {
     e->canwrite=0;
+    if (e->wantwrite && !e->kernelwantwrite)
+      io_wantwrite(d);
 #if defined(HAVE_SIGIO)
     if (d==alt_curwrite) {
 #if 0
diff --git a/io/iob_send.c b/io/iob_send.c
index 9ca3a3c..4c7e5fd 100644
--- a/io/iob_send.c
+++ b/io/iob_send.c
@@ -286,13 +286,13 @@ eagain:
 		  io_eagain_write(s);
 		  return -1;
 		}
-		sent = totalsent;
 		// fall through
 	      }
 	      // actual error
 	      break;
 	    }
-	    // if we get here, we wrote it all
+	    // if we get here, we wrote it all or we got an EAGAIN after
+	    // writing something. Treat as regular partial write.
 	    sent = totalsent;
 	  } else
 	    sent=sendmsg(s,&msg,MSG_MORE|ZEROCOPY);
@@ -354,6 +354,7 @@ eagain:
 	}
       }
       io_eagain_write(s);
+      return total;
     } else break;
   }
 abort: