Module Name: src
Committed By: riastradh
Date: Fri Aug 4 18:41:01 UTC 2023
Modified Files:
src/sys/arch/xen/xen: xennetback_xenbus.c
Log Message:
Revert "xennetback(4): Fix xennetback_evthandler loop."
PR kern/57560
To generate a diff of this commit:
cvs rdiff -u -r1.114 -r1.115 src/sys/arch/xen/xen/xennetback_xenbus.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/xen/xen/xennetback_xenbus.c
diff -u src/sys/arch/xen/xen/xennetback_xenbus.c:1.114 src/sys/arch/xen/xen/xennetback_xenbus.c:1.115
--- src/sys/arch/xen/xen/xennetback_xenbus.c:1.114 Fri Aug 4 18:40:49 2023
+++ src/sys/arch/xen/xen/xennetback_xenbus.c Fri Aug 4 18:41:01 2023
@@ -1,4 +1,4 @@
-/* $NetBSD: xennetback_xenbus.c,v 1.114 2023/08/04 18:40:49 riastradh Exp $ */
+/* $NetBSD: xennetback_xenbus.c,v 1.115 2023/08/04 18:41:01 riastradh Exp $ */
/*
* Copyright (c) 2006 Manuel Bouyer.
@@ -25,7 +25,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.114 2023/08/04 18:40:49 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.115 2023/08/04 18:41:01 riastradh Exp $");
#include <sys/types.h>
#include <sys/param.h>
@@ -805,7 +805,7 @@ xennetback_evthandler(void *arg)
netif_tx_request_t txreq;
struct mbuf *m, *m0 = NULL, *mlast = NULL;
int receive_pending;
- RING_IDX req_cons, req_prod;
+ RING_IDX req_cons;
int queued = 0, m0_len = 0;
struct xnetback_xstate *xst;
const bool discard = ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) !=
@@ -813,12 +813,17 @@ xennetback_evthandler(void *arg)
XENPRINTF(("xennetback_evthandler "));
req_cons = xneti->xni_txring.req_cons;
-again:
- req_prod = xneti->xni_txring.sring->req_prod;
- xen_rmb();
- while (req_cons != req_prod) {
+ while (1) {
+ xen_rmb(); /* be sure to read the request before updating */
+ xneti->xni_txring.req_cons = req_cons;
+ xen_wmb();
+ RING_FINAL_CHECK_FOR_REQUESTS(&xneti->xni_txring,
+ receive_pending);
+ if (receive_pending == 0)
+ break;
RING_COPY_REQUEST(&xneti->xni_txring, req_cons,
&txreq);
+ xen_rmb();
XENPRINTF(("%s pkt size %d\n", xneti->xni_if.if_xname,
txreq.size));
req_cons++;
@@ -957,12 +962,6 @@ mbuf_fail:
queued = 0;
}
}
- xen_wmb();
- RING_FINAL_CHECK_FOR_REQUESTS(&xneti->xni_txring, receive_pending);
- if (receive_pending)
- goto again;
- xneti->xni_txring.req_cons = req_cons;
-
if (m0) {
/* Queue empty, and still unfinished multi-fragment request */
printf("%s: dropped unfinished multi-fragment\n",
