diff options
-rw-r--r-- | hw/core/bus.c | 28 | ||||
-rw-r--r-- | hw/core/qdev.c | 37 | ||||
-rw-r--r-- | hw/scsi/scsi-bus.c | 12 | ||||
-rw-r--r-- | hw/scsi/virtio-scsi.c | 6 | ||||
-rw-r--r-- | include/hw/qdev-core.h | 9 |
5 files changed, 63 insertions, 29 deletions
diff --git a/hw/core/bus.c b/hw/core/bus.c index 6b987b6..a048385 100644 --- a/hw/core/bus.c +++ b/hw/core/bus.c @@ -49,12 +49,14 @@ int qbus_walk_children(BusState *bus, } } - QTAILQ_FOREACH(kid, &bus->children, sibling) { - err = qdev_walk_children(kid->child, - pre_devfn, pre_busfn, - post_devfn, post_busfn, opaque); - if (err < 0) { - return err; + WITH_RCU_READ_LOCK_GUARD() { + QTAILQ_FOREACH_RCU(kid, &bus->children, sibling) { + err = qdev_walk_children(kid->child, + pre_devfn, pre_busfn, + post_devfn, post_busfn, opaque); + if (err < 0) { + return err; + } } } @@ -90,8 +92,10 @@ static void bus_reset_child_foreach(Object *obj, ResettableChildCallback cb, BusState *bus = BUS(obj); BusChild *kid; - QTAILQ_FOREACH(kid, &bus->children, sibling) { - cb(OBJECT(kid->child), opaque, type); + WITH_RCU_READ_LOCK_GUARD() { + QTAILQ_FOREACH_RCU(kid, &bus->children, sibling) { + cb(OBJECT(kid->child), opaque, type); + } } } @@ -194,9 +198,11 @@ static void bus_set_realized(Object *obj, bool value, Error **errp) /* TODO: recursive realization */ } else if (!value && bus->realized) { - QTAILQ_FOREACH(kid, &bus->children, sibling) { - DeviceState *dev = kid->child; - qdev_unrealize(dev); + WITH_RCU_READ_LOCK_GUARD() { + QTAILQ_FOREACH_RCU(kid, &bus->children, sibling) { + DeviceState *dev = kid->child; + qdev_unrealize(dev); + } } if (bc->unrealize) { bc->unrealize(bus); diff --git a/hw/core/qdev.c b/hw/core/qdev.c index 74db78d..59e5e71 100644 --- a/hw/core/qdev.c +++ b/hw/core/qdev.c @@ -51,6 +51,12 @@ const VMStateDescription *qdev_get_vmsd(DeviceState *dev) return dc->vmsd; } +static void bus_free_bus_child(BusChild *kid) +{ + object_unref(OBJECT(kid->child)); + g_free(kid); +} + static void bus_remove_child(BusState *bus, DeviceState *child) { BusChild *kid; @@ -60,15 +66,16 @@ static void bus_remove_child(BusState *bus, DeviceState *child) char name[32]; snprintf(name, sizeof(name), "child[%d]", kid->index); - QTAILQ_REMOVE(&bus->children, kid, sibling); + QTAILQ_REMOVE_RCU(&bus->children, kid, sibling); bus->num_children--; /* This gives back ownership of kid->child back to us. */ object_property_del(OBJECT(bus), name); - object_unref(OBJECT(kid->child)); - g_free(kid); - return; + + /* free the bus kid, when it is safe to do so*/ + call_rcu(kid, bus_free_bus_child, rcu); + break; } } } @@ -83,7 +90,7 @@ static void bus_add_child(BusState *bus, DeviceState *child) kid->child = child; object_ref(OBJECT(kid->child)); - QTAILQ_INSERT_HEAD(&bus->children, kid, sibling); + QTAILQ_INSERT_HEAD_RCU(&bus->children, kid, sibling); /* This transfers ownership of kid->child to the property. */ snprintf(name, sizeof(name), "child[%d]", kid->index); @@ -672,17 +679,19 @@ DeviceState *qdev_find_recursive(BusState *bus, const char *id) DeviceState *ret; BusState *child; - QTAILQ_FOREACH(kid, &bus->children, sibling) { - DeviceState *dev = kid->child; + WITH_RCU_READ_LOCK_GUARD() { + QTAILQ_FOREACH_RCU(kid, &bus->children, sibling) { + DeviceState *dev = kid->child; - if (dev->id && strcmp(dev->id, id) == 0) { - return dev; - } + if (dev->id && strcmp(dev->id, id) == 0) { + return dev; + } - QLIST_FOREACH(child, &dev->child_bus, sibling) { - ret = qdev_find_recursive(child, id); - if (ret) { - return ret; + QLIST_FOREACH(child, &dev->child_bus, sibling) { + ret = qdev_find_recursive(child, id); + if (ret) { + return ret; + } } } } diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c index 6b1ed7a..4cf1f40 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -400,7 +400,10 @@ static bool scsi_target_emulate_report_luns(SCSITargetReq *r) id = r->req.dev->id; found_lun0 = false; n = 0; - QTAILQ_FOREACH(kid, &r->req.bus->qbus.children, sibling) { + + RCU_READ_LOCK_GUARD(); + + QTAILQ_FOREACH_RCU(kid, &r->req.bus->qbus.children, sibling) { DeviceState *qdev = kid->child; SCSIDevice *dev = SCSI_DEVICE(qdev); @@ -421,7 +424,7 @@ static bool scsi_target_emulate_report_luns(SCSITargetReq *r) memset(r->buf, 0, len); stl_be_p(&r->buf[0], n); i = found_lun0 ? 8 : 16; - QTAILQ_FOREACH(kid, &r->req.bus->qbus.children, sibling) { + QTAILQ_FOREACH_RCU(kid, &r->req.bus->qbus.children, sibling) { DeviceState *qdev = kid->child; SCSIDevice *dev = SCSI_DEVICE(qdev); @@ -430,6 +433,7 @@ static bool scsi_target_emulate_report_luns(SCSITargetReq *r) i += 8; } } + assert(i == n + 8); r->len = len; return true; @@ -1572,7 +1576,8 @@ SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int id, int lun) BusChild *kid; SCSIDevice *target_dev = NULL; - QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) { + RCU_READ_LOCK_GUARD(); + QTAILQ_FOREACH_RCU(kid, &bus->qbus.children, sibling) { DeviceState *qdev = kid->child; SCSIDevice *dev = SCSI_DEVICE(qdev); @@ -1591,6 +1596,7 @@ SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int id, int lun) } } } + return target_dev; } diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c index 3a71ea7..971afbb 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -367,12 +367,16 @@ static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req) case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET: target = req->req.tmf.lun[1]; s->resetting++; - QTAILQ_FOREACH(kid, &s->bus.qbus.children, sibling) { + + rcu_read_lock(); + QTAILQ_FOREACH_RCU(kid, &s->bus.qbus.children, sibling) { d = SCSI_DEVICE(kid->child); if (d->channel == 0 && d->id == target) { qdev_reset_all(&d->qdev); } } + rcu_read_unlock(); + s->resetting--; break; diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h index 14d476c..2c6307e 100644 --- a/include/hw/qdev-core.h +++ b/include/hw/qdev-core.h @@ -3,6 +3,8 @@ #include "qemu/queue.h" #include "qemu/bitmap.h" +#include "qemu/rcu.h" +#include "qemu/rcu_queue.h" #include "qom/object.h" #include "hw/hotplug.h" #include "hw/resettable.h" @@ -238,6 +240,7 @@ struct BusClass { }; typedef struct BusChild { + struct rcu_head rcu; DeviceState *child; int index; QTAILQ_ENTRY(BusChild) sibling; @@ -258,6 +261,12 @@ struct BusState { int max_index; bool realized; int num_children; + + /* + * children is a RCU QTAILQ, thus readers must use RCU to access it, + * and writers must hold the big qemu lock + */ + QTAILQ_HEAD(, BusChild) children; QLIST_ENTRY(BusState) sibling; ResettableState reset; |