On Mon, 24 Jul 2017, Juergen Gross wrote: > On 22/07/17 02:11, Stefano Stabellini wrote: > > Send PVCALLS_CONNECT to the backend. Allocate a new ring and evtchn for > > the active socket. > > > > Introduce a data structure to keep track of sockets. Introduce a > > waitqueue to allow the frontend to wait on data coming from the backend > > on the active socket (recvmsg command). > > > > Two mutexes (one of reads and one for writes) will be used to protect > > the active socket in and out rings from concurrent accesses. > > > > sock->sk->sk_send_head is not used for ip sockets: reuse the field to > > store a pointer to the struct sock_mapping corresponding to the socket. > > This way, we can easily get the struct sock_mapping from the struct > > socket. > > > > Convert the struct socket pointer into an uint64_t and use it as id for > > the new socket to pass to the backend. > > > > Signed-off-by: Stefano Stabellini <stef...@aporeto.com> > > CC: boris.ostrov...@oracle.com > > CC: jgr...@suse.com > > --- > > drivers/xen/pvcalls-front.c | 153 > > ++++++++++++++++++++++++++++++++++++++++++++ > > drivers/xen/pvcalls-front.h | 2 + > > 2 files changed, 155 insertions(+) > > > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > > index 7933c73..0d305e0 100644 > > --- a/drivers/xen/pvcalls-front.c > > +++ b/drivers/xen/pvcalls-front.c > > @@ -13,6 +13,8 @@ > > */ > > > > #include <linux/module.h> > > +#include <linux/net.h> > > +#include <linux/socket.h> > > > > #include <xen/events.h> > > #include <xen/grant_table.h> > > @@ -20,6 +22,8 @@ > > #include <xen/xenbus.h> > > #include <xen/interface/io/pvcalls.h> > > > > +#include <net/sock.h> > > + > > #define PVCALLS_INVALID_ID (UINT_MAX) > > #define RING_ORDER XENBUS_MAX_RING_GRANT_ORDER > > #define PVCALLS_NR_REQ_PER_RING __CONST_RING_SIZE(xen_pvcalls, > > XEN_PAGE_SIZE) > > @@ -38,6 +42,24 @@ struct pvcalls_bedata { > > }; > > struct xenbus_device *pvcalls_front_dev; > > > > +struct sock_mapping { > > + bool active_socket; > > + struct list_head list; > > + struct socket *sock; > > + union { > > + struct { > > + int irq; > > + grant_ref_t ref; > > + struct pvcalls_data_intf *ring; > > + struct pvcalls_data data; > > + struct mutex in_mutex; > > + struct mutex out_mutex; > > + > > + wait_queue_head_t inflight_conn_req; > > + } active; > > + }; > > +}; > > + > > static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) > > { > > struct xenbus_device *dev = dev_id; > > @@ -80,6 +102,18 @@ static irqreturn_t pvcalls_front_event_handler(int irq, > > void *dev_id) > > return IRQ_HANDLED; > > } > > > > +static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map) > > +{ > > + struct sock_mapping *map = sock_map; > > + > > + if (map == NULL) > > + return IRQ_HANDLED; > > + > > + wake_up_interruptible(&map->active.inflight_conn_req); > > + > > + return IRQ_HANDLED; > > +} > > + > > int pvcalls_front_socket(struct socket *sock) > > { > > struct pvcalls_bedata *bedata; > > @@ -134,6 +168,125 @@ int pvcalls_front_socket(struct socket *sock) > > return ret; > > } > > > > +static struct sock_mapping *create_active(int *evtchn) > > +{ > > + struct sock_mapping *map = NULL; > > + void *bytes; > > + int ret, irq = -1, i; > > + > > + map = kzalloc(sizeof(*map), GFP_KERNEL); > > + if (map == NULL) > > + return NULL; > > + > > + init_waitqueue_head(&map->active.inflight_conn_req); > > + > > + map->active.ring = (struct pvcalls_data_intf *) > > + __get_free_page(GFP_KERNEL | __GFP_ZERO); > > + if (map->active.ring == NULL) > > + goto out_error; > > + memset(map->active.ring, 0, XEN_PAGE_SIZE); > > + map->active.ring->ring_order = RING_ORDER; > > + bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, > > + map->active.ring->ring_order); > > + if (bytes == NULL) > > + goto out_error; > > + for (i = 0; i < (1 << map->active.ring->ring_order); i++) > > + map->active.ring->ref[i] = gnttab_grant_foreign_access( > > + pvcalls_front_dev->otherend_id, > > + pfn_to_gfn(virt_to_pfn(bytes) + i), 0); > > + > > + map->active.ref = gnttab_grant_foreign_access( > > + pvcalls_front_dev->otherend_id, > > + pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0); > > + > > + ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn); > > + if (ret) > > + goto out_error; > > You are leaking bytes here in case of error.
well spotted, I'll move "map->active.data.in = bytes" up > > + map->active.data.in = bytes; > > + map->active.data.out = bytes + > > + XEN_FLEX_RING_SIZE(map->active.ring->ring_order); > > + irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler, > > + 0, "pvcalls-frontend", map); > > + if (irq < 0) > > + goto out_error; > > + > > + map->active.irq = irq; > > + map->active_socket = true; > > + mutex_init(&map->active.in_mutex); > > + mutex_init(&map->active.out_mutex); > > + > > + return map; > > + > > +out_error: > > + if (irq >= 0) > > + unbind_from_irqhandler(irq, map); > > + else if (*evtchn >= 0) > > + xenbus_free_evtchn(pvcalls_front_dev, *evtchn); > > + kfree(map->active.data.in); > > + kfree(map->active.ring); > > + kfree(map); > > + return NULL; > > +} > > + > > +int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, > > + int addr_len, int flags) > > +{ > > + struct pvcalls_bedata *bedata; > > + struct sock_mapping *map = NULL; > > + struct xen_pvcalls_request *req; > > + int notify, req_id, ret, evtchn; > > + > > + if (!pvcalls_front_dev) > > + return -ENETUNREACH; > > + if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM) > > + return -ENOTSUPP; > > + > > + bedata = dev_get_drvdata(&pvcalls_front_dev->dev); > > + > > + 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; > > + } > > + > > + map = create_active(&evtchn); > > + if (!map) > > + return -ENOMEM; > > spin_unlock()? Yes, I'll fix > > + > > + req = RING_GET_REQUEST(&bedata->ring, req_id); > > + req->req_id = req_id; > > + req->cmd = PVCALLS_CONNECT; > > + req->u.connect.id = (uint64_t)sock; > > + memcpy(req->u.connect.addr, addr, sizeof(*addr)); > > + req->u.connect.len = addr_len; > > + req->u.connect.flags = flags; > > + req->u.connect.ref = map->active.ref; > > + req->u.connect.evtchn = evtchn; > > + > > + list_add_tail(&map->list, &bedata->socket_mappings); > > + map->sock = sock; > > + WRITE_ONCE(sock->sk->sk_send_head, (void *)map); > > + > > + 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); > > + > > + ret = bedata->rsp[req_id].ret; > > + /* read ret, then set this rsp slot to be reused */ > > + smp_mb(); > > + WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID); > > + return ret; > > +} > > + > > 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 b7dabed..63b0417 100644 > > --- a/drivers/xen/pvcalls-front.h > > +++ b/drivers/xen/pvcalls-front.h > > @@ -4,5 +4,7 @@ > > #include <linux/net.h> > > > > int pvcalls_front_socket(struct socket *sock); > > +int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, > > + int addr_len, int flags); > > > > #endif > > >