Re: Weird piecemeal reads over socketpair() pipe breaks up small writes into even smaller reads.

[Bill Fenner]

How about a 1-line fix:

Index: uipc_usrreq.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/uipc_usrreq.c,v
retrieving revision 1.37
diff -u -r1.37 uipc_usrreq.c
--- uipc_usrreq.c       1998/10/25 17:44:51     1.37
+++ uipc_usrreq.c       1999/02/15 07:09:12
@@ -348,7 +348,8 @@
                unp->unp_conn->unp_mbcnt = rcv->sb_mbcnt;
                snd->sb_hiwat -= rcv->sb_cc - unp->unp_conn->unp_cc;
                unp->unp_conn->unp_cc = rcv->sb_cc;
-               sorwakeup(so2);
+               if (!(flags & PRUS_MORETOCOME))
+                       sorwakeup(so2);
                m = 0;
 #undef snd
 #undef rcv

Unfortunately, this apparently unearths a bug in the ?:?:?:
expression in sosend(), so try this diff too.

Index: uipc_socket.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/uipc_socket.c,v
retrieving revision 1.51
diff -u -r1.51 uipc_socket.c
--- uipc_socket.c       1999/01/20 17:45:22     1.51
+++ uipc_socket.c       1999/02/15 07:09:25
@@ -388,6 +405,7 @@
        register long space, len, resid;
        int clen = 0, error, s, dontroute, mlen;
        int atomic = sosendallatonce(so) || top;
+       int pru_flags;
 
        if (uio)
                resid = uio->uio_resid;
@@ -518,21 +536,24 @@
                    } while (space > 0 && atomic);
                    if (dontroute)
                            so->so_options |= SO_DONTROUTE;
+                   pru_flags = 0;
+                   if (flags & MSG_OOB)
+                       pru_flags |= PRUS_OOB;
+                   /*
+                    * If the user set MSG_EOF, the protocol
+                    * understands this flag and nothing left to
+                    * send then set PRUS_EOF.
+                    */
+                   if ((flags & MSG_EOF) &&
+                       (so->so_proto->pr_flags & PR_IMPLOPCL) &&
+                       (resid <= 0))
+                       pru_flags |= PRUS_EOF;
+                   /* If there is more to send set PRUS_MORETOCOME */
+                   if (resid > 0 && space > 0)
+                       pru_flags |= PRUS_MORETOCOME;
                    s = splnet();                               /* XXX */
                    error = (*so->so_proto->pr_usrreqs->pru_send)(so,
-                       (flags & MSG_OOB) ? PRUS_OOB :
-                       /*
-                        * If the user set MSG_EOF, the protocol
-                        * understands this flag and nothing left to
-                        * send then use PRU_SEND_EOF instead of PRU_SEND.
-                        */
-                       ((flags & MSG_EOF) &&
-                        (so->so_proto->pr_flags & PR_IMPLOPCL) &&
-                        (resid <= 0)) ?
-                               PRUS_EOF :
-                       /* If there is more to send set PRUS_MORETOCOME */
-                       (resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
-                       top, addr, control, p);
+                       pru_flags, top, addr, control, p);
                    splx(s);
                    if (dontroute)
                            so->so_options &= ~SO_DONTROUTE;


  Bill

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