Module Name: src
Committed By: bouyer
Date: Sun Aug 7 17:10:35 UTC 2011
Modified Files:
src/sys/arch/xen/xen: xbdback_xenbus.c
Log Message:
Several fixes to the continuation engine:
- make sure to enter the continuation loop at splbio(), and add some
KASSERT() for this.
- When a flush operation is enqueued to the workqueue, make sure the
continuation loop can't be restarted by a previous workqueue
completion or an event. We can't restart it at this point because
the flush even is still recorded as the current I/O.
For this add a xbdback_co_cache_doflush_wait() which acts as a noop;
the workqueue callback will restart the loop once the flush is complete.
Should fix "kernel diagnostic assertion xbd_io->xio_mapped == 0" panics
reported by Jeff Rizzo on port-xen@.
To generate a diff of this commit:
cvs rdiff -u -r1.42 -r1.43 src/sys/arch/xen/xen/xbdback_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/xbdback_xenbus.c
diff -u src/sys/arch/xen/xen/xbdback_xenbus.c:1.42 src/sys/arch/xen/xen/xbdback_xenbus.c:1.43
--- src/sys/arch/xen/xen/xbdback_xenbus.c:1.42 Thu Aug 4 18:01:49 2011
+++ src/sys/arch/xen/xen/xbdback_xenbus.c Sun Aug 7 17:10:35 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: xbdback_xenbus.c,v 1.42 2011/08/04 18:01:49 bouyer Exp $ */
+/* $NetBSD: xbdback_xenbus.c,v 1.43 2011/08/07 17:10:35 bouyer Exp $ */
/*
* Copyright (c) 2006 Manuel Bouyer.
@@ -26,7 +26,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.42 2011/08/04 18:01:49 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.43 2011/08/07 17:10:35 bouyer Exp $");
#include <sys/types.h>
#include <sys/param.h>
@@ -287,6 +287,7 @@
static void *xbdback_co_cache_flush(struct xbdback_instance *, void *);
static void *xbdback_co_cache_flush2(struct xbdback_instance *, void *);
static void *xbdback_co_cache_doflush(struct xbdback_instance *, void *);
+static void *xbdback_co_cache_doflush_wait(struct xbdback_instance *, void *);
static void *xbdback_co_io(struct xbdback_instance *, void *);
static void *xbdback_co_io_gotreq(struct xbdback_instance *, void *);
@@ -967,6 +968,8 @@
{
(void)obj;
if (xbdi->xbdi_io != NULL) {
+ KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ ||
+ xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE);
xbdi->xbdi_cont = xbdback_co_flush;
xbdi->xbdi_cont_aux = xbdback_co_main_done2;
} else {
@@ -999,9 +1002,13 @@
xbdback_co_cache_flush(struct xbdback_instance *xbdi, void *obj)
{
(void)obj;
+ KASSERT(curcpu()->ci_ilevel >= IPL_BIO);
XENPRINTF(("xbdback_co_cache_flush %p %p\n", xbdi, obj));
if (xbdi->xbdi_io != NULL) {
/* Some I/Os are required for this instance. Process them. */
+ KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ ||
+ xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE);
+ KASSERT(xbdi->xbdi_pendingreqs == 0);
xbdi->xbdi_cont = xbdback_co_flush;
xbdi->xbdi_cont_aux = xbdback_co_cache_flush2;
} else {
@@ -1016,8 +1023,10 @@
(void)obj;
XENPRINTF(("xbdback_co_cache_flush2 %p %p\n", xbdi, obj));
if (xbdi->xbdi_pendingreqs > 0) {
- /* There are pending requests.
- * Event or iodone() will restart processing */
+ /*
+ * There are pending requests.
+ * Event or iodone() will restart processing
+ */
xbdi->xbdi_cont = NULL;
xbdi_put(xbdi);
return NULL;
@@ -1039,7 +1048,17 @@
xbd_io->xio_flush_id = xbdi->xbdi_xen_req.id;
workqueue_enqueue(xbdback_workqueue, &xbdi->xbdi_io->xio_work, NULL);
/* xbdback_do_io() will advance req pointer and restart processing */
- xbdi->xbdi_cont = NULL;
+ xbdi->xbdi_cont = xbdback_co_cache_doflush_wait;
+ return NULL;
+}
+
+/* wait for the flush work to complete */
+static void *
+xbdback_co_cache_doflush_wait(struct xbdback_instance *xbdi, void *obj)
+{
+ (void)obj;
+ /* abort the continuation loop; xbdback_do_io() will restart it */
+ xbdi->xbdi_cont = xbdback_co_cache_doflush_wait;
return NULL;
}
@@ -1067,6 +1086,8 @@
goto end;
}
+ KASSERT(req->operation == BLKIF_OP_READ ||
+ req->operation == BLKIF_OP_WRITE);
if (req->operation == BLKIF_OP_WRITE) {
if (xbdi->xbdi_ro) {
error = EROFS;
@@ -1122,6 +1143,8 @@
xrq->rq_ioerrs = 0;
xrq->rq_id = xbdi->xbdi_xen_req.id;
xrq->rq_operation = xbdi->xbdi_xen_req.operation;
+ KASSERT(xbdi->xbdi_req->rq_operation == BLKIF_OP_READ ||
+ xbdi->xbdi_req->rq_operation == BLKIF_OP_WRITE);
/*
* Request-level reasons not to coalesce: different device,
@@ -1144,6 +1167,8 @@
xbdi->xbdi_next_sector =
xbdi->xbdi_xen_req.sector_number;
xbdi->xbdi_cont_aux = xbdi->xbdi_cont;
+ KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ ||
+ xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE);
xbdi->xbdi_cont = xbdback_co_flush;
}
} else {
@@ -1159,6 +1184,8 @@
struct xbdback_io *xio;
(void)obj;
+ KASSERT(xbdi->xbdi_req->rq_operation == BLKIF_OP_READ ||
+ xbdi->xbdi_req->rq_operation == BLKIF_OP_WRITE);
if (xbdi->xbdi_segno < xbdi->xbdi_xen_req.nr_segments) {
uint8_t this_fs, this_ls, last_fs, last_ls;
grant_ref_t thisgrt, lastgrt;
@@ -1211,6 +1238,10 @@
xbdi->xbdi_same_page = 1;
} else {
xbdi->xbdi_cont_aux = xbdback_co_io_loop;
+ KASSERT(xbdi->xbdi_io->xio_operation ==
+ BLKIF_OP_READ ||
+ xbdi->xbdi_io->xio_operation ==
+ BLKIF_OP_WRITE);
xbdi->xbdi_cont = xbdback_co_flush;
return xbdi;
}
@@ -1239,6 +1270,7 @@
vaddr_t start_offset; /* start offset in vm area */
int buf_flags;
+ KASSERT(curcpu()->ci_ilevel >= IPL_BIO);
xbdi_get(xbdi);
atomic_inc_uint(&xbdi->xbdi_pendingreqs);
@@ -1385,6 +1417,7 @@
xbdback_do_io(struct work *wk, void *dummy)
{
struct xbdback_io *xbd_io = (void *)wk;
+ int s;
KASSERT(&xbd_io->xio_work == wk);
switch (xbd_io->xio_operation) {
@@ -1410,9 +1443,11 @@
xbdback_pool_put(&xbdback_io_pool, xbd_io);
xbdi_put(xbdi);
/* handle next IO */
+ s = splbio();
xbdi->xbdi_io = NULL;
xbdi->xbdi_cont = xbdback_co_main_incr;
xbdback_trampoline(xbdi, xbdi);
+ splx(s);
break;
}
case BLKIF_OP_READ:
@@ -1730,8 +1765,9 @@
} else {
struct xbdback_instance *xbdi = SIMPLEQ_FIRST(&pp->q);
SIMPLEQ_REMOVE_HEAD(&pp->q, xbdi_on_hold);
- splx(s);
+ (void)splbio();
xbdback_trampoline(xbdi, item);
+ splx(s);
}
}
@@ -1743,6 +1779,7 @@
xbdback_trampoline(struct xbdback_instance *xbdi, void *obj)
{
xbdback_cont_t cont;
+ KASSERT(curcpu()->ci_ilevel >= IPL_BIO);
while(obj != NULL && xbdi->xbdi_cont != NULL) {
cont = xbdi->xbdi_cont;
