Module Name: src
Committed By: riz
Date: Fri Aug 12 20:48:48 UTC 2011
Modified Files:
src/sys/arch/xen/xen [netbsd-5]: xbdback_xenbus.c
Log Message:
Pull up following revision(s) (requested by bouyer in ticket #1654):
sys/arch/xen/xen/xbdback_xenbus.c: revision 1.42
sys/arch/xen/xen/xbdback_xenbus.c: revision 1.43
sys/arch/xen/xen/xbdback_xenbus.c: revision 1.44
Make sure to call xbdback_trampoline() at splbio()
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@.
Add a comment explaing why a flush workqueue is handled differently from
read/write workqueue requests.
To generate a diff of this commit:
cvs rdiff -u -r1.20.4.5 -r1.20.4.6 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:1.20.4.5 src/sys/arch/xen/xen/xbdback_xenbus.c:1.20.4.6
--- src/sys/arch/xen/xen/xbdback_xenbus.c:1.20.4.5 Sat Jun 18 16:38:26 2011
+++ src/sys/arch/xen/xen/xbdback_xenbus.c Fri Aug 12 20:48:47 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: xbdback_xenbus.c,v 1.20.4.5 2011/06/18 16:38:26 bouyer Exp $ */
+/* $NetBSD: xbdback_xenbus.c,v 1.20.4.6 2011/08/12 20:48:47 riz Exp $ */
/*
* Copyright (c) 2006 Manuel Bouyer.
@@ -31,7 +31,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.20.4.5 2011/06/18 16:38:26 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.20.4.6 2011/08/12 20:48:47 riz Exp $");
#include <sys/types.h>
#include <sys/param.h>
@@ -283,6 +283,7 @@
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 *);
@@ -941,6 +942,8 @@
{
(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 {
@@ -966,8 +969,13 @@
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 {
@@ -982,7 +990,10 @@
(void)obj;
XENPRINTF(("xbdback_co_cache_flush2 %p %p\n", xbdi, obj));
if (xbdi->xbdi_pendingreqs > 0) {
- /* 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;
@@ -1002,8 +1013,23 @@
xbd_io->xio_operation = xbdi->xbdi_xen_req.operation;
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 = xbdback_co_cache_doflush;
+ /*
+ * xbdback_do_io() will advance req pointer and restart processing.
+ * Note that we could probably set xbdi->xbdi_io to NULL and
+ * let the processing continue, but we really want to wait
+ * for the flush to complete before doing any more work.
+ */
+ 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;
}
@@ -1027,7 +1053,9 @@
goto end;
}
- if (xbdi->xbdi_xen_req.operation == BLKIF_OP_WRITE) {
+ KASSERT(req->operation == BLKIF_OP_READ ||
+ req->operation == BLKIF_OP_WRITE);
+ if (req->operation == BLKIF_OP_WRITE) {
if (xbdi->xbdi_ro) {
error = EROFS;
goto end;
@@ -1076,6 +1104,8 @@
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,
@@ -1098,6 +1128,8 @@
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 {
@@ -1113,6 +1145,8 @@
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;
@@ -1165,6 +1199,10 @@
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;
}
@@ -1194,6 +1232,7 @@
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);
@@ -1331,6 +1370,7 @@
xbdback_do_io(struct work *wk, void *dummy)
{
struct xbdback_io *xbd_io = (void *)wk;
+ int s;
KASSERT(&xbd_io->xio_work == wk);
if (xbd_io->xio_operation == BLKIF_OP_FLUSH_DISKCACHE) {
@@ -1354,9 +1394,11 @@
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);
return;
}
@@ -1595,19 +1637,17 @@
case 0:
xbd_io->xio_mapped = 1;
SIMPLEQ_REMOVE_HEAD(&xbdback_shmq, xbdi_on_hold);
- splx(s);
+ (void)splbio();
xbdback_trampoline(xbdi, xbdi);
- s = splvm();
break;
default:
SIMPLEQ_REMOVE_HEAD(&xbdback_shmq, xbdi_on_hold);
- splx(s);
+ (void)splbio();
printf("xbdback_shm_callback: xen_shm error %d\n",
error);
xbdi->xbdi_cont = xbdi->xbdi_cont_aux;
xbdback_io_error(xbd_io, error);
xbdback_trampoline(xbdi, xbdi);
- s = splvm();
break;
}
}
@@ -1670,8 +1710,9 @@
} 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);
}
}
@@ -1679,6 +1720,7 @@
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;
