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@.
This commit is contained in:
bouyer
parent
e24714e44d
commit
48ed379bb7
@ -1,4 +1,4 @@
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/* $NetBSD: xbdback_xenbus.c,v 1.42 2011/08/04 18:01:49 bouyer Exp $ */
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/* $NetBSD: xbdback_xenbus.c,v 1.43 2011/08/07 17:10:35 bouyer Exp $ */
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/*
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* Copyright (c) 2006 Manuel Bouyer.
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@ -26,7 +26,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.42 2011/08/04 18:01:49 bouyer Exp $");
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__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.43 2011/08/07 17:10:35 bouyer Exp $");
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#include <sys/types.h>
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#include <sys/param.h>
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@ -287,6 +287,7 @@ static void *xbdback_co_main_done2(struct xbdback_instance *, void *);
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static void *xbdback_co_cache_flush(struct xbdback_instance *, void *);
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static void *xbdback_co_cache_flush2(struct xbdback_instance *, void *);
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static void *xbdback_co_cache_doflush(struct xbdback_instance *, void *);
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static void *xbdback_co_cache_doflush_wait(struct xbdback_instance *, void *);
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static void *xbdback_co_io(struct xbdback_instance *, void *);
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static void *xbdback_co_io_gotreq(struct xbdback_instance *, void *);
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@ -967,6 +968,8 @@ xbdback_co_main_done(struct xbdback_instance *xbdi, void *obj)
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{
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(void)obj;
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if (xbdi->xbdi_io != NULL) {
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KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ ||
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xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE);
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xbdi->xbdi_cont = xbdback_co_flush;
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xbdi->xbdi_cont_aux = xbdback_co_main_done2;
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} else {
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@ -999,9 +1002,13 @@ static void *
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xbdback_co_cache_flush(struct xbdback_instance *xbdi, void *obj)
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{
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(void)obj;
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KASSERT(curcpu()->ci_ilevel >= IPL_BIO);
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XENPRINTF(("xbdback_co_cache_flush %p %p\n", xbdi, obj));
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if (xbdi->xbdi_io != NULL) {
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/* Some I/Os are required for this instance. Process them. */
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KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ ||
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xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE);
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KASSERT(xbdi->xbdi_pendingreqs == 0);
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xbdi->xbdi_cont = xbdback_co_flush;
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xbdi->xbdi_cont_aux = xbdback_co_cache_flush2;
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} else {
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@ -1016,8 +1023,10 @@ xbdback_co_cache_flush2(struct xbdback_instance *xbdi, void *obj)
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(void)obj;
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XENPRINTF(("xbdback_co_cache_flush2 %p %p\n", xbdi, obj));
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if (xbdi->xbdi_pendingreqs > 0) {
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/* There are pending requests.
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* Event or iodone() will restart processing */
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/*
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* There are pending requests.
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* Event or iodone() will restart processing
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*/
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xbdi->xbdi_cont = NULL;
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xbdi_put(xbdi);
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return NULL;
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@ -1039,7 +1048,17 @@ xbdback_co_cache_doflush(struct xbdback_instance *xbdi, void *obj)
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xbd_io->xio_flush_id = xbdi->xbdi_xen_req.id;
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workqueue_enqueue(xbdback_workqueue, &xbdi->xbdi_io->xio_work, NULL);
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/* xbdback_do_io() will advance req pointer and restart processing */
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xbdi->xbdi_cont = NULL;
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xbdi->xbdi_cont = xbdback_co_cache_doflush_wait;
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return NULL;
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}
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/* wait for the flush work to complete */
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static void *
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xbdback_co_cache_doflush_wait(struct xbdback_instance *xbdi, void *obj)
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{
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(void)obj;
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/* abort the continuation loop; xbdback_do_io() will restart it */
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xbdi->xbdi_cont = xbdback_co_cache_doflush_wait;
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return NULL;
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}
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@ -1067,6 +1086,8 @@ xbdback_co_io(struct xbdback_instance *xbdi, void *obj)
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goto end;
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}
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KASSERT(req->operation == BLKIF_OP_READ ||
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req->operation == BLKIF_OP_WRITE);
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if (req->operation == BLKIF_OP_WRITE) {
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if (xbdi->xbdi_ro) {
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error = EROFS;
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@ -1122,6 +1143,8 @@ xbdback_co_io_gotreq(struct xbdback_instance *xbdi, void *obj)
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xrq->rq_ioerrs = 0;
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xrq->rq_id = xbdi->xbdi_xen_req.id;
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xrq->rq_operation = xbdi->xbdi_xen_req.operation;
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KASSERT(xbdi->xbdi_req->rq_operation == BLKIF_OP_READ ||
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xbdi->xbdi_req->rq_operation == BLKIF_OP_WRITE);
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/*
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* Request-level reasons not to coalesce: different device,
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@ -1144,6 +1167,8 @@ xbdback_co_io_gotreq(struct xbdback_instance *xbdi, void *obj)
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xbdi->xbdi_next_sector =
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xbdi->xbdi_xen_req.sector_number;
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xbdi->xbdi_cont_aux = xbdi->xbdi_cont;
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KASSERT(xbdi->xbdi_io->xio_operation == BLKIF_OP_READ ||
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xbdi->xbdi_io->xio_operation == BLKIF_OP_WRITE);
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xbdi->xbdi_cont = xbdback_co_flush;
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}
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} else {
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@ -1159,6 +1184,8 @@ xbdback_co_io_loop(struct xbdback_instance *xbdi, void *obj)
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struct xbdback_io *xio;
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(void)obj;
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KASSERT(xbdi->xbdi_req->rq_operation == BLKIF_OP_READ ||
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xbdi->xbdi_req->rq_operation == BLKIF_OP_WRITE);
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if (xbdi->xbdi_segno < xbdi->xbdi_xen_req.nr_segments) {
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uint8_t this_fs, this_ls, last_fs, last_ls;
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grant_ref_t thisgrt, lastgrt;
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@ -1211,6 +1238,10 @@ xbdback_co_io_loop(struct xbdback_instance *xbdi, void *obj)
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xbdi->xbdi_same_page = 1;
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} else {
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xbdi->xbdi_cont_aux = xbdback_co_io_loop;
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KASSERT(xbdi->xbdi_io->xio_operation ==
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BLKIF_OP_READ ||
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xbdi->xbdi_io->xio_operation ==
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BLKIF_OP_WRITE);
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xbdi->xbdi_cont = xbdback_co_flush;
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return xbdi;
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}
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@ -1239,6 +1270,7 @@ xbdback_co_io_gotio(struct xbdback_instance *xbdi, void *obj)
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vaddr_t start_offset; /* start offset in vm area */
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int buf_flags;
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KASSERT(curcpu()->ci_ilevel >= IPL_BIO);
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xbdi_get(xbdi);
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atomic_inc_uint(&xbdi->xbdi_pendingreqs);
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@ -1385,6 +1417,7 @@ static void
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xbdback_do_io(struct work *wk, void *dummy)
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{
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struct xbdback_io *xbd_io = (void *)wk;
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int s;
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KASSERT(&xbd_io->xio_work == wk);
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switch (xbd_io->xio_operation) {
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@ -1410,9 +1443,11 @@ xbdback_do_io(struct work *wk, void *dummy)
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xbdback_pool_put(&xbdback_io_pool, xbd_io);
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xbdi_put(xbdi);
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/* handle next IO */
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s = splbio();
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xbdi->xbdi_io = NULL;
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xbdi->xbdi_cont = xbdback_co_main_incr;
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xbdback_trampoline(xbdi, xbdi);
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splx(s);
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break;
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}
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case BLKIF_OP_READ:
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@ -1730,8 +1765,9 @@ static void xbdback_pool_put(struct xbdback_pool *pp, void *item)
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} else {
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struct xbdback_instance *xbdi = SIMPLEQ_FIRST(&pp->q);
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SIMPLEQ_REMOVE_HEAD(&pp->q, xbdi_on_hold);
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splx(s);
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(void)splbio();
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xbdback_trampoline(xbdi, item);
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splx(s);
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}
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}
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@ -1743,6 +1779,7 @@ static void
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xbdback_trampoline(struct xbdback_instance *xbdi, void *obj)
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{
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xbdback_cont_t cont;
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KASSERT(curcpu()->ci_ilevel >= IPL_BIO);
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while(obj != NULL && xbdi->xbdi_cont != NULL) {
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cont = xbdi->xbdi_cont;
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