[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v1 11/13] xen/pvcalls: implement release command
On 22/07/17 02:12, Stefano Stabellini wrote: > Send PVCALLS_RELEASE to the backend and wait for a reply. Take both > in_mutex and out_mutex to avoid concurrent accesses. Then, free the > socket. > > Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx> > CC: boris.ostrovsky@xxxxxxxxxx > CC: jgross@xxxxxxxx > --- > drivers/xen/pvcalls-front.c | 86 > +++++++++++++++++++++++++++++++++++++++++++++ > drivers/xen/pvcalls-front.h | 1 + > 2 files changed, 87 insertions(+) > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > index b6cfb7d..bd3dfac 100644 > --- a/drivers/xen/pvcalls-front.c > +++ b/drivers/xen/pvcalls-front.c > @@ -174,6 +174,24 @@ static irqreturn_t pvcalls_front_conn_handler(int irq, > void *sock_map) > return IRQ_HANDLED; > } > > +static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, > + struct sock_mapping *map) > +{ > + int i; > + > + spin_lock(&bedata->pvcallss_lock); > + if (!list_empty(&map->list)) > + list_del_init(&map->list); > + spin_unlock(&bedata->pvcallss_lock); > + > + /* what if the thread waiting still need access? */ Is this handled? If not, why is it no problem? > + for (i = 0; i < (1 << map->active.ring->ring_order); i++) > + gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0); > + gnttab_end_foreign_access(map->active.ref, 0, 0); > + free_page((unsigned long)map->active.ring); > + unbind_from_irqhandler(map->active.irq, map); > +} > + > int pvcalls_front_socket(struct socket *sock) > { > struct pvcalls_bedata *bedata; > @@ -805,6 +823,74 @@ unsigned int pvcalls_front_poll(struct file *file, > struct socket *sock, > return pvcalls_front_poll_passive(file, bedata, map, wait); > } > > +int pvcalls_front_release(struct socket *sock) > +{ > + struct pvcalls_bedata *bedata; > + struct sock_mapping *map; > + int req_id, notify; > + struct xen_pvcalls_request *req; > + > + if (!pvcalls_front_dev) > + return -EIO; > + bedata = dev_get_drvdata(&pvcalls_front_dev->dev); > + if (!bedata) > + return -EIO; > + > + if (sock->sk == NULL) > + return 0; > + > + map = (struct sock_mapping *) READ_ONCE(sock->sk->sk_send_head); > + if (map == NULL) > + return 0; > + WRITE_ONCE(sock->sk->sk_send_head, NULL); > + > + spin_lock(&bedata->pvcallss_lock); > + req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1); > + BUG_ON(req_id >= PVCALLS_NR_REQ_PER_RING); > + if (RING_FULL(&bedata->ring) || > + READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) { > + spin_unlock(&bedata->pvcallss_lock); > + return -EAGAIN; Isn't it a problem you already cleared sock->sk->sk_send_head? Juergen > + } > + req = RING_GET_REQUEST(&bedata->ring, req_id); > + req->req_id = req_id; > + req->cmd = PVCALLS_RELEASE; > + req->u.release.id = (uint64_t)sock; > + > + bedata->ring.req_prod_pvt++; > + RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); > + spin_unlock(&bedata->pvcallss_lock); > + if (notify) > + notify_remote_via_irq(bedata->irq); > + > + wait_event(bedata->inflight_req, > + READ_ONCE(bedata->rsp[req_id].req_id) == req_id); > + > + if (map->active_socket) { > + /* > + * Set in_error and wake up inflight_conn_req to force > + * recvmsg waiters to exit. > + */ > + map->active.ring->in_error = -EBADF; > + wake_up_interruptible(&map->active.inflight_conn_req); > + > + mutex_lock(&map->active.in_mutex); > + mutex_lock(&map->active.out_mutex); > + pvcalls_front_free_map(bedata, map); > + mutex_unlock(&map->active.out_mutex); > + mutex_unlock(&map->active.in_mutex); > + kfree(map); > + } else { > + spin_lock(&bedata->pvcallss_lock); > + list_del_init(&map->list); > + kfree(map); > + spin_unlock(&bedata->pvcallss_lock); > + } > + WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID); > + > + return 0; > +} > + > static const struct xenbus_device_id pvcalls_front_ids[] = { > { "pvcalls" }, > { "" } > diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h > index 25e05b8..3332978 100644 > --- a/drivers/xen/pvcalls-front.h > +++ b/drivers/xen/pvcalls-front.h > @@ -23,5 +23,6 @@ int pvcalls_front_recvmsg(struct socket *sock, > unsigned int pvcalls_front_poll(struct file *file, > struct socket *sock, > poll_table *wait); > +int pvcalls_front_release(struct socket *sock); > > #endif > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |