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authorStefano Stabellini <sstabellini@kernel.org>2017-10-31 01:41:00 +0300
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2017-10-31 16:05:53 +0300
commitae0d04052e077ccb71772bf5c7cb1049f4d587d2 (patch)
tree899cad4c8057bb02218757c7f87a76ee41696c39 /drivers/xen/pvcalls-front.c
parent45ddce214a797de65c0418bebf90c1b564c3ee3d (diff)
downloadlinux-ae0d04052e077ccb71772bf5c7cb1049f4d587d2.tar.xz
xen/pvcalls: implement recvmsg
Implement recvmsg by copying data from the "in" ring. If not enough data is available and the recvmsg call is blocking, then wait on the inflight_conn_req waitqueue. Take the active socket in_mutex so that only one function can access the ring at any given time. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen/pvcalls-front.c')
-rw-r--r--drivers/xen/pvcalls-front.c111
1 files changed, 111 insertions, 0 deletions
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 76725780e767..24ffdc90e217 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -117,6 +117,20 @@ static bool pvcalls_front_write_todo(struct sock_mapping *map)
return !!(size - pvcalls_queued(prod, cons, size));
}
+static bool pvcalls_front_read_todo(struct sock_mapping *map)
+{
+ struct pvcalls_data_intf *intf = map->active.ring;
+ RING_IDX cons, prod;
+ int32_t error;
+
+ cons = intf->in_cons;
+ prod = intf->in_prod;
+ error = intf->in_error;
+ return (error != 0 ||
+ pvcalls_queued(prod, cons,
+ XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER)) != 0);
+}
+
static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
{
struct xenbus_device *dev = dev_id;
@@ -484,6 +498,103 @@ again:
return tot_sent;
}
+static int __read_ring(struct pvcalls_data_intf *intf,
+ struct pvcalls_data *data,
+ struct iov_iter *msg_iter,
+ size_t len, int flags)
+{
+ RING_IDX cons, prod, size, masked_prod, masked_cons;
+ RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
+ int32_t error;
+
+ cons = intf->in_cons;
+ prod = intf->in_prod;
+ error = intf->in_error;
+ /* get pointers before reading from the ring */
+ virt_rmb();
+ if (error < 0)
+ return error;
+
+ size = pvcalls_queued(prod, cons, array_size);
+ masked_prod = pvcalls_mask(prod, array_size);
+ masked_cons = pvcalls_mask(cons, array_size);
+
+ if (size == 0)
+ return 0;
+
+ if (len > size)
+ len = size;
+
+ if (masked_prod > masked_cons) {
+ len = copy_to_iter(data->in + masked_cons, len, msg_iter);
+ } else {
+ if (len > (array_size - masked_cons)) {
+ int ret = copy_to_iter(data->in + masked_cons,
+ array_size - masked_cons, msg_iter);
+ if (ret != array_size - masked_cons) {
+ len = ret;
+ goto out;
+ }
+ len = ret + copy_to_iter(data->in, len - ret, msg_iter);
+ } else {
+ len = copy_to_iter(data->in + masked_cons, len, msg_iter);
+ }
+ }
+out:
+ /* read data from the ring before increasing the index */
+ virt_mb();
+ if (!(flags & MSG_PEEK))
+ intf->in_cons += len;
+
+ return len;
+}
+
+int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+ int flags)
+{
+ struct pvcalls_bedata *bedata;
+ int ret;
+ struct sock_mapping *map;
+
+ if (flags & (MSG_CMSG_CLOEXEC|MSG_ERRQUEUE|MSG_OOB|MSG_TRUNC))
+ return -EOPNOTSUPP;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -ENOTCONN;
+ }
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *) sock->sk->sk_send_head;
+ if (!map) {
+ pvcalls_exit();
+ return -ENOTSOCK;
+ }
+
+ mutex_lock(&map->active.in_mutex);
+ if (len > XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER))
+ len = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
+
+ while (!(flags & MSG_DONTWAIT) && !pvcalls_front_read_todo(map)) {
+ wait_event_interruptible(map->active.inflight_conn_req,
+ pvcalls_front_read_todo(map));
+ }
+ ret = __read_ring(map->active.ring, &map->active.data,
+ &msg->msg_iter, len, flags);
+
+ if (ret > 0)
+ notify_remote_via_irq(map->active.irq);
+ if (ret == 0)
+ ret = (flags & MSG_DONTWAIT) ? -EAGAIN : 0;
+ if (ret == -ENOTCONN)
+ ret = 0;
+
+ mutex_unlock(&map->active.in_mutex);
+ pvcalls_exit();
+ return ret;
+}
+
int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
{
struct pvcalls_bedata *bedata;