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Date: Fri, 21 Jul 2017 17:12:01 -0700
From: Stefano Stabellini <sstabellini@...nel.org>
To: xen-devel@...ts.xen.org
Cc: linux-kernel@...r.kernel.org, sstabellini@...nel.org,
jgross@...e.com, boris.ostrovsky@...cle.com,
Stefano Stabellini <stefano@...reto.com>
Subject: [PATCH v1 11/13] xen/pvcalls: implement release command
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@...reto.com>
CC: boris.ostrovsky@...cle.com
CC: jgross@...e.com
---
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? */
+ 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;
+ }
+ 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
--
1.9.1
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