Author: nwhitehorn
Date: Mon Feb 23 20:38:00 2015
New Revision: 279217
URL: https://svnweb.freebsd.org/changeset/base/279217
Log:
Fix race in interrupt handling that could cause IO to hang up under heavy
load.
Modified:
head/sys/powerpc/pseries/phyp_vscsi.c
Modified: head/sys/powerpc/pseries/phyp_vscsi.c
==============================================================================
--- head/sys/powerpc/pseries/phyp_vscsi.c Mon Feb 23 20:36:07 2015
(r279216)
+++ head/sys/powerpc/pseries/phyp_vscsi.c Mon Feb 23 20:38:00 2015
(r279217)
@@ -931,10 +931,11 @@ vscsi_check_response_queue(struct vscsi_
mtx_assert(&sc->io_lock, MA_OWNED);
- phyp_hcall(H_VIO_SIGNAL, sc->unit, 0);
- bus_dmamap_sync(sc->crq_tag, sc->crq_map, BUS_DMASYNC_POSTREAD);
-
while (sc->crq_queue[sc->cur_crq].valid != 0) {
+ /* The hypercalls at both ends of this are not optimal */
+ phyp_hcall(H_VIO_SIGNAL, sc->unit, 0);
+ bus_dmamap_sync(sc->crq_tag, sc->crq_map, BUS_DMASYNC_POSTREAD);
+
crq = &sc->crq_queue[sc->cur_crq];
switch (crq->valid) {
@@ -983,9 +984,9 @@ vscsi_check_response_queue(struct vscsi_
crq->valid = 0;
sc->cur_crq = (sc->cur_crq + 1) % sc->n_crqs;
- };
- bus_dmamap_sync(sc->crq_tag, sc->crq_map, BUS_DMASYNC_PREWRITE);
- phyp_hcall(H_VIO_SIGNAL, sc->unit, 1);
+ bus_dmamap_sync(sc->crq_tag, sc->crq_map, BUS_DMASYNC_PREWRITE);
+ phyp_hcall(H_VIO_SIGNAL, sc->unit, 1);
+ }
}
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