From cae1c11414912bf77a62aebd65ced321f0b9da51 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Mon, 27 Oct 2008 15:22:46 +0000 Subject: [PATCH] uwb: reference count reservations Reference counting the struct uwb_rsv's is safer and easier to get right than the transferring ownership of the structures from the PAL to reservation manager. This fixes an oops in the debug PAL after a reservation timed out. Signed-off-by: David Vrabel --- drivers/usb/wusbcore/reservation.c | 7 ++--- drivers/uwb/rsv.c | 48 ++++++++++++++++++++---------- drivers/uwb/uwb-debug.c | 13 ++++++-- include/linux/uwb.h | 1 + 4 files changed, 46 insertions(+), 23 deletions(-) diff --git a/drivers/usb/wusbcore/reservation.c b/drivers/usb/wusbcore/reservation.c index fc63e77ded2d..7b6525dac2f1 100644 --- a/drivers/usb/wusbcore/reservation.c +++ b/drivers/usb/wusbcore/reservation.c @@ -59,7 +59,6 @@ static void wusbhc_rsv_complete_cb(struct uwb_rsv *rsv) case UWB_RSV_STATE_NONE: dev_dbg(dev, "removed reservation\n"); wusbhc_bwa_set(wusbhc, 0, NULL); - wusbhc->rsv = NULL; break; default: dev_dbg(dev, "unexpected reservation state: %d\n", rsv->state); @@ -105,11 +104,11 @@ int wusbhc_rsv_establish(struct wusbhc *wusbhc) /** - * wusbhc_rsv_terminate - terminate any cluster reservation + * wusbhc_rsv_terminate - terminate the cluster reservation * @wusbhc: the WUSB host whose reservation is to be terminated */ void wusbhc_rsv_terminate(struct wusbhc *wusbhc) { - if (wusbhc->rsv) - uwb_rsv_terminate(wusbhc->rsv); + uwb_rsv_terminate(wusbhc->rsv); + uwb_rsv_destroy(wusbhc->rsv); } diff --git a/drivers/uwb/rsv.c b/drivers/uwb/rsv.c index e4facae46e0d..bcc41a4a6606 100644 --- a/drivers/uwb/rsv.c +++ b/drivers/uwb/rsv.c @@ -82,6 +82,23 @@ static void uwb_rsv_dump(struct uwb_rsv *rsv) dev_dbg(dev, "rsv %s -> %s: %s\n", owner, target, uwb_rsv_state_str(rsv->state)); } +static void uwb_rsv_release(struct kref *kref) +{ + struct uwb_rsv *rsv = container_of(kref, struct uwb_rsv, kref); + + kfree(rsv); +} + +static void uwb_rsv_get(struct uwb_rsv *rsv) +{ + kref_get(&rsv->kref); +} + +static void uwb_rsv_put(struct uwb_rsv *rsv) +{ + kref_put(&rsv->kref, uwb_rsv_release); +} + /* * Get a free stream index for a reservation. * @@ -325,6 +342,7 @@ static struct uwb_rsv *uwb_rsv_alloc(struct uwb_rc *rc) INIT_LIST_HEAD(&rsv->rc_node); INIT_LIST_HEAD(&rsv->pal_node); + kref_init(&rsv->kref); init_timer(&rsv->timer); rsv->timer.function = uwb_rsv_timer; rsv->timer.data = (unsigned long)rsv; @@ -334,14 +352,6 @@ static struct uwb_rsv *uwb_rsv_alloc(struct uwb_rc *rc) return rsv; } -static void uwb_rsv_free(struct uwb_rsv *rsv) -{ - uwb_dev_put(rsv->owner); - if (rsv->target.type == UWB_RSV_TARGET_DEV) - uwb_dev_put(rsv->target.dev); - kfree(rsv); -} - /** * uwb_rsv_create - allocate and initialize a UWB reservation structure * @rc: the radio controller @@ -375,23 +385,23 @@ void uwb_rsv_remove(struct uwb_rsv *rsv) if (rsv->state != UWB_RSV_STATE_NONE) uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE); del_timer_sync(&rsv->timer); - list_del(&rsv->rc_node); - uwb_rsv_free(rsv); + uwb_dev_put(rsv->owner); + if (rsv->target.type == UWB_RSV_TARGET_DEV) + uwb_dev_put(rsv->target.dev); + + list_del_init(&rsv->rc_node); + uwb_rsv_put(rsv); } /** * uwb_rsv_destroy - free a UWB reservation structure * @rsv: the reservation to free * - * The reservation will be terminated if it is pending or established. + * The reservation must already be terminated. */ void uwb_rsv_destroy(struct uwb_rsv *rsv) { - struct uwb_rc *rc = rsv->rc; - - mutex_lock(&rc->rsvs_mutex); - uwb_rsv_remove(rsv); - mutex_unlock(&rc->rsvs_mutex); + uwb_rsv_put(rsv); } EXPORT_SYMBOL_GPL(uwb_rsv_destroy); @@ -423,6 +433,7 @@ int uwb_rsv_establish(struct uwb_rsv *rsv) goto out; } + uwb_rsv_get(rsv); list_add_tail(&rsv->rc_node, &rc->reservations); rsv->owner = &rc->uwb_dev; uwb_dev_get(rsv->owner); @@ -478,9 +489,14 @@ EXPORT_SYMBOL_GPL(uwb_rsv_terminate); * * Reservation requests from peers are denied unless a PAL accepts it * by calling this function. + * + * The PAL call uwb_rsv_destroy() for all accepted reservations before + * calling uwb_pal_unregister(). */ void uwb_rsv_accept(struct uwb_rsv *rsv, uwb_rsv_cb_f cb, void *pal_priv) { + uwb_rsv_get(rsv); + rsv->callback = cb; rsv->pal_priv = pal_priv; rsv->state = UWB_RSV_STATE_T_ACCEPTED; diff --git a/drivers/uwb/uwb-debug.c b/drivers/uwb/uwb-debug.c index 6d232c35d07d..6db641e45313 100644 --- a/drivers/uwb/uwb-debug.c +++ b/drivers/uwb/uwb-debug.c @@ -104,6 +104,11 @@ static void uwb_dbg_rsv_cb(struct uwb_rsv *rsv) dev_dbg(dev, "debug: rsv %s -> %s: %s\n", owner, target, uwb_rsv_state_str(rsv->state)); + + if (rsv->state == UWB_RSV_STATE_NONE) { + list_del(&rsv->pal_node); + uwb_rsv_destroy(rsv); + } } static int cmd_rsv_establish(struct uwb_rc *rc, @@ -153,11 +158,11 @@ static int cmd_rsv_terminate(struct uwb_rc *rc, found = rsv; break; } + i++; } if (!found) return -EINVAL; - list_del(&found->pal_node); uwb_rsv_terminate(found); return 0; @@ -287,8 +292,10 @@ static void uwb_dbg_new_rsv(struct uwb_rsv *rsv) { struct uwb_rc *rc = rsv->rc; - if (rc->dbg->accept) + if (rc->dbg->accept) { + list_add_tail(&rsv->pal_node, &rc->dbg->rsvs); uwb_rsv_accept(rsv, uwb_dbg_rsv_cb, NULL); + } } /** @@ -336,7 +343,7 @@ void uwb_dbg_del_rc(struct uwb_rc *rc) return; list_for_each_entry_safe(rsv, t, &rc->dbg->rsvs, pal_node) { - uwb_rsv_destroy(rsv); + uwb_rsv_terminate(rsv); } uwb_pal_unregister(rc, &rc->dbg->pal); diff --git a/include/linux/uwb.h b/include/linux/uwb.h index f9ccbd9a2ced..010ee708304d 100644 --- a/include/linux/uwb.h +++ b/include/linux/uwb.h @@ -201,6 +201,7 @@ struct uwb_rsv { struct uwb_rc *rc; struct list_head rc_node; struct list_head pal_node; + struct kref kref; struct uwb_dev *owner; struct uwb_rsv_target target; -- 2.34.1