Re: [PATCH v1 07/13] xen/pvcalls: implement accept command

2017-07-24 Thread Stefano Stabellini 
On Mon, 24 Jul 2017, Juergen Gross wrote:
> On 22/07/17 02:11, Stefano Stabellini wrote:
> > Send PVCALLS_ACCEPT to the backend. Allocate a new active socket. Make
> > sure that only one accept command is executed at any given time by
> > setting PVCALLS_FLAG_ACCEPT_INFLIGHT and waiting on the
> > inflight_accept_req waitqueue.
> > 
> > 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.
> > 
> > Convert the new 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 
> > CC: boris.ostrov...@oracle.com
> > CC: jgr...@suse.com
> > ---
> >  drivers/xen/pvcalls-front.c | 79 
> > +
> >  drivers/xen/pvcalls-front.h |  3 ++
> >  2 files changed, 82 insertions(+)
> > 
> > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
> > index 80fd5fb..f3a04a2 100644
> > --- a/drivers/xen/pvcalls-front.c
> > +++ b/drivers/xen/pvcalls-front.c
> > @@ -410,6 +410,85 @@ int pvcalls_front_listen(struct socket *sock, int 
> > backlog)
> > return ret;
> >  }
> >  
> > +int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int 
> > flags)
> > +{
> > +   struct pvcalls_bedata *bedata;
> > +   struct sock_mapping *map;
> > +   struct sock_mapping *map2 = NULL;
> > +   struct xen_pvcalls_request *req;
> > +   int notify, req_id, ret, evtchn;
> > +
> > +   if (!pvcalls_front_dev)
> > +   return -ENOTCONN;
> > +   bedata = dev_get_drvdata(_front_dev->dev);
> > +
> > +   map = (struct sock_mapping *) READ_ONCE(sock->sk->sk_send_head);
> > +   if (!map)
> > +   return -ENOTSOCK;
> > +
> > +   if (map->passive.status != PVCALLS_STATUS_LISTEN)
> > +   return -EINVAL;
> > +
> > +   /*
> > +* Backend only supports 1 inflight accept request, will return
> > +* errors for the others
> > +*/
> > +   if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
> > +(void *)>passive.flags)) {
> > +   if (wait_event_interruptible(map->passive.inflight_accept_req,
> > +   !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
> > + (void *)>passive.flags))
> > +   != 0)
> > +   return -EINTR;
> > +   }
> > +
> > +
> > +   newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL);
> > +   if (newsock->sk == NULL)
> > +   return -ENOMEM;
> > +
> > +   spin_lock(>pvcallss_lock);
> > +   req_id = bedata->ring.req_prod_pvt & (RING_SIZE(>ring) - 1);
> > +   BUG_ON(req_id >= PVCALLS_NR_REQ_PER_RING);
> 
> BUG_ON()?
> 
> > +   if (RING_FULL(>ring) ||
> > +   READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) {
> > +   spin_unlock(>pvcallss_lock);
> > +   return -EAGAIN;
> 
> Leaking newsock->sk?

I'll fix


> > +   }
> > +
> > +   map2 = create_active();
> > +
> > +   req = RING_GET_REQUEST(>ring, req_id);
> > +   req->req_id = req_id;
> > +   req->cmd = PVCALLS_ACCEPT;
> > +   req->u.accept.id = (uint64_t) sock;
> > +   req->u.accept.ref = map2->active.ref;
> > +   req->u.accept.id_new = (uint64_t) newsock;
> > +   req->u.accept.evtchn = evtchn;
> > +
> > +   list_add_tail(>list, >socket_mappings);
> > +   WRITE_ONCE(newsock->sk->sk_send_head, (void *)map2);
> > +   map2->sock = newsock;
> > +
> > +   bedata->ring.req_prod_pvt++;
> > +   RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(>ring, notify);
> > +   spin_unlock(>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);
> > +
> > +   clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)>passive.flags);
> > +   wake_up(>passive.inflight_accept_req);
> > +
> > +   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 aa8fe10..ab4f1da 100644
> > --- a/drivers/xen/pvcalls-front.h
> > +++ b/drivers/xen/pvcalls-front.h
> > @@ -10,5 +10,8 @@ int pvcalls_front_bind(struct socket *sock,
> >struct sockaddr *addr,
> >int addr_len);
> >  int pvcalls_front_listen(struct socket *sock, int backlog);
> > +int pvcalls_front_accept(struct socket *sock,
> > +struct socket *newsock,
> > +int flags);
> >  
> >  #endif
> > 
>

Re: [PATCH v1 07/13] xen/pvcalls: implement accept command

2017-07-24 Thread Stefano Stabellini 
On Mon, 24 Jul 2017, Juergen Gross wrote:
> On 22/07/17 02:11, Stefano Stabellini wrote:
> > Send PVCALLS_ACCEPT to the backend. Allocate a new active socket. Make
> > sure that only one accept command is executed at any given time by
> > setting PVCALLS_FLAG_ACCEPT_INFLIGHT and waiting on the
> > inflight_accept_req waitqueue.
> > 
> > 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.
> > 
> > Convert the new 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 
> > CC: boris.ostrov...@oracle.com
> > CC: jgr...@suse.com
> > ---
> >  drivers/xen/pvcalls-front.c | 79 
> > +
> >  drivers/xen/pvcalls-front.h |  3 ++
> >  2 files changed, 82 insertions(+)
> > 
> > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
> > index 80fd5fb..f3a04a2 100644
> > --- a/drivers/xen/pvcalls-front.c
> > +++ b/drivers/xen/pvcalls-front.c
> > @@ -410,6 +410,85 @@ int pvcalls_front_listen(struct socket *sock, int 
> > backlog)
> > return ret;
> >  }
> >  
> > +int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int 
> > flags)
> > +{
> > +   struct pvcalls_bedata *bedata;
> > +   struct sock_mapping *map;
> > +   struct sock_mapping *map2 = NULL;
> > +   struct xen_pvcalls_request *req;
> > +   int notify, req_id, ret, evtchn;
> > +
> > +   if (!pvcalls_front_dev)
> > +   return -ENOTCONN;
> > +   bedata = dev_get_drvdata(_front_dev->dev);
> > +
> > +   map = (struct sock_mapping *) READ_ONCE(sock->sk->sk_send_head);
> > +   if (!map)
> > +   return -ENOTSOCK;
> > +
> > +   if (map->passive.status != PVCALLS_STATUS_LISTEN)
> > +   return -EINVAL;
> > +
> > +   /*
> > +* Backend only supports 1 inflight accept request, will return
> > +* errors for the others
> > +*/
> > +   if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
> > +(void *)>passive.flags)) {
> > +   if (wait_event_interruptible(map->passive.inflight_accept_req,
> > +   !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
> > + (void *)>passive.flags))
> > +   != 0)
> > +   return -EINTR;
> > +   }
> > +
> > +
> > +   newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL);
> > +   if (newsock->sk == NULL)
> > +   return -ENOMEM;
> > +
> > +   spin_lock(>pvcallss_lock);
> > +   req_id = bedata->ring.req_prod_pvt & (RING_SIZE(>ring) - 1);
> > +   BUG_ON(req_id >= PVCALLS_NR_REQ_PER_RING);
> 
> BUG_ON()?
> 
> > +   if (RING_FULL(>ring) ||
> > +   READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) {
> > +   spin_unlock(>pvcallss_lock);
> > +   return -EAGAIN;
> 
> Leaking newsock->sk?

I'll fix


> > +   }
> > +
> > +   map2 = create_active();
> > +
> > +   req = RING_GET_REQUEST(>ring, req_id);
> > +   req->req_id = req_id;
> > +   req->cmd = PVCALLS_ACCEPT;
> > +   req->u.accept.id = (uint64_t) sock;
> > +   req->u.accept.ref = map2->active.ref;
> > +   req->u.accept.id_new = (uint64_t) newsock;
> > +   req->u.accept.evtchn = evtchn;
> > +
> > +   list_add_tail(>list, >socket_mappings);
> > +   WRITE_ONCE(newsock->sk->sk_send_head, (void *)map2);
> > +   map2->sock = newsock;
> > +
> > +   bedata->ring.req_prod_pvt++;
> > +   RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(>ring, notify);
> > +   spin_unlock(>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);
> > +
> > +   clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)>passive.flags);
> > +   wake_up(>passive.inflight_accept_req);
> > +
> > +   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 aa8fe10..ab4f1da 100644
> > --- a/drivers/xen/pvcalls-front.h
> > +++ b/drivers/xen/pvcalls-front.h
> > @@ -10,5 +10,8 @@ int pvcalls_front_bind(struct socket *sock,
> >struct sockaddr *addr,
> >int addr_len);
> >  int pvcalls_front_listen(struct socket *sock, int backlog);
> > +int pvcalls_front_accept(struct socket *sock,
> > +struct socket *newsock,
> > +int flags);
> >  
> >  #endif
> > 
>

Re: [PATCH v1 07/13] xen/pvcalls: implement accept command

2017-07-24 Thread Juergen Gross 
On 22/07/17 02:11, Stefano Stabellini wrote:
> Send PVCALLS_ACCEPT to the backend. Allocate a new active socket. Make
> sure that only one accept command is executed at any given time by
> setting PVCALLS_FLAG_ACCEPT_INFLIGHT and waiting on the
> inflight_accept_req waitqueue.
> 
> 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.
> 
> Convert the new 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 
> CC: boris.ostrov...@oracle.com
> CC: jgr...@suse.com
> ---
>  drivers/xen/pvcalls-front.c | 79 
> +
>  drivers/xen/pvcalls-front.h |  3 ++
>  2 files changed, 82 insertions(+)
> 
> diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
> index 80fd5fb..f3a04a2 100644
> --- a/drivers/xen/pvcalls-front.c
> +++ b/drivers/xen/pvcalls-front.c
> @@ -410,6 +410,85 @@ int pvcalls_front_listen(struct socket *sock, int 
> backlog)
>   return ret;
>  }
>  
> +int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int 
> flags)
> +{
> + struct pvcalls_bedata *bedata;
> + struct sock_mapping *map;
> + struct sock_mapping *map2 = NULL;
> + struct xen_pvcalls_request *req;
> + int notify, req_id, ret, evtchn;
> +
> + if (!pvcalls_front_dev)
> + return -ENOTCONN;
> + bedata = dev_get_drvdata(_front_dev->dev);
> +
> + map = (struct sock_mapping *) READ_ONCE(sock->sk->sk_send_head);
> + if (!map)
> + return -ENOTSOCK;
> +
> + if (map->passive.status != PVCALLS_STATUS_LISTEN)
> + return -EINVAL;
> +
> + /*
> +  * Backend only supports 1 inflight accept request, will return
> +  * errors for the others
> +  */
> + if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
> +  (void *)>passive.flags)) {
> + if (wait_event_interruptible(map->passive.inflight_accept_req,
> + !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
> +   (void *)>passive.flags))
> + != 0)
> + return -EINTR;
> + }
> +
> +
> + newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL);
> + if (newsock->sk == NULL)
> + return -ENOMEM;
> +
> + spin_lock(>pvcallss_lock);
> + req_id = bedata->ring.req_prod_pvt & (RING_SIZE(>ring) - 1);
> + BUG_ON(req_id >= PVCALLS_NR_REQ_PER_RING);

BUG_ON()?

> + if (RING_FULL(>ring) ||
> + READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) {
> + spin_unlock(>pvcallss_lock);
> + return -EAGAIN;

Leaking newsock->sk?


Juergen

> + }
> +
> + map2 = create_active();
> +
> + req = RING_GET_REQUEST(>ring, req_id);
> + req->req_id = req_id;
> + req->cmd = PVCALLS_ACCEPT;
> + req->u.accept.id = (uint64_t) sock;
> + req->u.accept.ref = map2->active.ref;
> + req->u.accept.id_new = (uint64_t) newsock;
> + req->u.accept.evtchn = evtchn;
> +
> + list_add_tail(>list, >socket_mappings);
> + WRITE_ONCE(newsock->sk->sk_send_head, (void *)map2);
> + map2->sock = newsock;
> +
> + bedata->ring.req_prod_pvt++;
> + RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(>ring, notify);
> + spin_unlock(>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);
> +
> + clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)>passive.flags);
> + wake_up(>passive.inflight_accept_req);
> +
> + 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 aa8fe10..ab4f1da 100644
> --- a/drivers/xen/pvcalls-front.h
> +++ b/drivers/xen/pvcalls-front.h
> @@ -10,5 +10,8 @@ int pvcalls_front_bind(struct socket *sock,
>  struct sockaddr *addr,
>  int addr_len);
>  int pvcalls_front_listen(struct socket *sock, int backlog);
> +int pvcalls_front_accept(struct socket *sock,
> +  struct socket *newsock,
> +  int flags);
>  
>  #endif
>

Re: [PATCH v1 07/13] xen/pvcalls: implement accept command

2017-07-24 Thread Juergen Gross 
On 22/07/17 02:11, Stefano Stabellini wrote:
> Send PVCALLS_ACCEPT to the backend. Allocate a new active socket. Make
> sure that only one accept command is executed at any given time by
> setting PVCALLS_FLAG_ACCEPT_INFLIGHT and waiting on the
> inflight_accept_req waitqueue.
> 
> 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.
> 
> Convert the new 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 
> CC: boris.ostrov...@oracle.com
> CC: jgr...@suse.com
> ---
>  drivers/xen/pvcalls-front.c | 79 
> +
>  drivers/xen/pvcalls-front.h |  3 ++
>  2 files changed, 82 insertions(+)
> 
> diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
> index 80fd5fb..f3a04a2 100644
> --- a/drivers/xen/pvcalls-front.c
> +++ b/drivers/xen/pvcalls-front.c
> @@ -410,6 +410,85 @@ int pvcalls_front_listen(struct socket *sock, int 
> backlog)
>   return ret;
>  }
>  
> +int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int 
> flags)
> +{
> + struct pvcalls_bedata *bedata;
> + struct sock_mapping *map;
> + struct sock_mapping *map2 = NULL;
> + struct xen_pvcalls_request *req;
> + int notify, req_id, ret, evtchn;
> +
> + if (!pvcalls_front_dev)
> + return -ENOTCONN;
> + bedata = dev_get_drvdata(_front_dev->dev);
> +
> + map = (struct sock_mapping *) READ_ONCE(sock->sk->sk_send_head);
> + if (!map)
> + return -ENOTSOCK;
> +
> + if (map->passive.status != PVCALLS_STATUS_LISTEN)
> + return -EINVAL;
> +
> + /*
> +  * Backend only supports 1 inflight accept request, will return
> +  * errors for the others
> +  */
> + if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
> +  (void *)>passive.flags)) {
> + if (wait_event_interruptible(map->passive.inflight_accept_req,
> + !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
> +   (void *)>passive.flags))
> + != 0)
> + return -EINTR;
> + }
> +
> +
> + newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL);
> + if (newsock->sk == NULL)
> + return -ENOMEM;
> +
> + spin_lock(>pvcallss_lock);
> + req_id = bedata->ring.req_prod_pvt & (RING_SIZE(>ring) - 1);
> + BUG_ON(req_id >= PVCALLS_NR_REQ_PER_RING);

BUG_ON()?

> + if (RING_FULL(>ring) ||
> + READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) {
> + spin_unlock(>pvcallss_lock);
> + return -EAGAIN;

Leaking newsock->sk?


Juergen

> + }
> +
> + map2 = create_active();
> +
> + req = RING_GET_REQUEST(>ring, req_id);
> + req->req_id = req_id;
> + req->cmd = PVCALLS_ACCEPT;
> + req->u.accept.id = (uint64_t) sock;
> + req->u.accept.ref = map2->active.ref;
> + req->u.accept.id_new = (uint64_t) newsock;
> + req->u.accept.evtchn = evtchn;
> +
> + list_add_tail(>list, >socket_mappings);
> + WRITE_ONCE(newsock->sk->sk_send_head, (void *)map2);
> + map2->sock = newsock;
> +
> + bedata->ring.req_prod_pvt++;
> + RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(>ring, notify);
> + spin_unlock(>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);
> +
> + clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)>passive.flags);
> + wake_up(>passive.inflight_accept_req);
> +
> + 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 aa8fe10..ab4f1da 100644
> --- a/drivers/xen/pvcalls-front.h
> +++ b/drivers/xen/pvcalls-front.h
> @@ -10,5 +10,8 @@ int pvcalls_front_bind(struct socket *sock,
>  struct sockaddr *addr,
>  int addr_len);
>  int pvcalls_front_listen(struct socket *sock, int backlog);
> +int pvcalls_front_accept(struct socket *sock,
> +  struct socket *newsock,
> +  int flags);
>  
>  #endif
>

[PATCH v1 07/13] xen/pvcalls: implement accept command

2017-07-21 Thread Stefano Stabellini 
Send PVCALLS_ACCEPT to the backend. Allocate a new active socket. Make
sure that only one accept command is executed at any given time by
setting PVCALLS_FLAG_ACCEPT_INFLIGHT and waiting on the
inflight_accept_req waitqueue.

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.

Convert the new 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 
CC: boris.ostrov...@oracle.com
CC: jgr...@suse.com
---
 drivers/xen/pvcalls-front.c | 79 +
 drivers/xen/pvcalls-front.h |  3 ++
 2 files changed, 82 insertions(+)

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 80fd5fb..f3a04a2 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -410,6 +410,85 @@ int pvcalls_front_listen(struct socket *sock, int backlog)
return ret;
 }
 
+int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int 
flags)
+{
+   struct pvcalls_bedata *bedata;
+   struct sock_mapping *map;
+   struct sock_mapping *map2 = NULL;
+   struct xen_pvcalls_request *req;
+   int notify, req_id, ret, evtchn;
+
+   if (!pvcalls_front_dev)
+   return -ENOTCONN;
+   bedata = dev_get_drvdata(_front_dev->dev);
+
+   map = (struct sock_mapping *) READ_ONCE(sock->sk->sk_send_head);
+   if (!map)
+   return -ENOTSOCK;
+
+   if (map->passive.status != PVCALLS_STATUS_LISTEN)
+   return -EINVAL;
+
+   /*
+* Backend only supports 1 inflight accept request, will return
+* errors for the others
+*/
+   if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+(void *)>passive.flags)) {
+   if (wait_event_interruptible(map->passive.inflight_accept_req,
+   !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)>passive.flags))
+   != 0)
+   return -EINTR;
+   }
+
+
+   newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL);
+   if (newsock->sk == NULL)
+   return -ENOMEM;
+
+   spin_lock(>pvcallss_lock);
+   req_id = bedata->ring.req_prod_pvt & (RING_SIZE(>ring) - 1);
+   BUG_ON(req_id >= PVCALLS_NR_REQ_PER_RING);
+   if (RING_FULL(>ring) ||
+   READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) {
+   spin_unlock(>pvcallss_lock);
+   return -EAGAIN;
+   }
+
+   map2 = create_active();
+
+   req = RING_GET_REQUEST(>ring, req_id);
+   req->req_id = req_id;
+   req->cmd = PVCALLS_ACCEPT;
+   req->u.accept.id = (uint64_t) sock;
+   req->u.accept.ref = map2->active.ref;
+   req->u.accept.id_new = (uint64_t) newsock;
+   req->u.accept.evtchn = evtchn;
+
+   list_add_tail(>list, >socket_mappings);
+   WRITE_ONCE(newsock->sk->sk_send_head, (void *)map2);
+   map2->sock = newsock;
+
+   bedata->ring.req_prod_pvt++;
+   RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(>ring, notify);
+   spin_unlock(>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);
+
+   clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)>passive.flags);
+   wake_up(>passive.inflight_accept_req);
+
+   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 aa8fe10..ab4f1da 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -10,5 +10,8 @@ int pvcalls_front_bind(struct socket *sock,
   struct sockaddr *addr,
   int addr_len);
 int pvcalls_front_listen(struct socket *sock, int backlog);
+int pvcalls_front_accept(struct socket *sock,
+struct socket *newsock,
+int flags);
 
 #endif
-- 
1.9.1

[PATCH v1 07/13] xen/pvcalls: implement accept command

2017-07-21 Thread Stefano Stabellini 
Send PVCALLS_ACCEPT to the backend. Allocate a new active socket. Make
sure that only one accept command is executed at any given time by
setting PVCALLS_FLAG_ACCEPT_INFLIGHT and waiting on the
inflight_accept_req waitqueue.

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.

Convert the new 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 
CC: boris.ostrov...@oracle.com
CC: jgr...@suse.com
---
 drivers/xen/pvcalls-front.c | 79 +
 drivers/xen/pvcalls-front.h |  3 ++
 2 files changed, 82 insertions(+)

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 80fd5fb..f3a04a2 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -410,6 +410,85 @@ int pvcalls_front_listen(struct socket *sock, int backlog)
return ret;
 }
 
+int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int 
flags)
+{
+   struct pvcalls_bedata *bedata;
+   struct sock_mapping *map;
+   struct sock_mapping *map2 = NULL;
+   struct xen_pvcalls_request *req;
+   int notify, req_id, ret, evtchn;
+
+   if (!pvcalls_front_dev)
+   return -ENOTCONN;
+   bedata = dev_get_drvdata(_front_dev->dev);
+
+   map = (struct sock_mapping *) READ_ONCE(sock->sk->sk_send_head);
+   if (!map)
+   return -ENOTSOCK;
+
+   if (map->passive.status != PVCALLS_STATUS_LISTEN)
+   return -EINVAL;
+
+   /*
+* Backend only supports 1 inflight accept request, will return
+* errors for the others
+*/
+   if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+(void *)>passive.flags)) {
+   if (wait_event_interruptible(map->passive.inflight_accept_req,
+   !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)>passive.flags))
+   != 0)
+   return -EINTR;
+   }
+
+
+   newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL);
+   if (newsock->sk == NULL)
+   return -ENOMEM;
+
+   spin_lock(>pvcallss_lock);
+   req_id = bedata->ring.req_prod_pvt & (RING_SIZE(>ring) - 1);
+   BUG_ON(req_id >= PVCALLS_NR_REQ_PER_RING);
+   if (RING_FULL(>ring) ||
+   READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) {
+   spin_unlock(>pvcallss_lock);
+   return -EAGAIN;
+   }
+
+   map2 = create_active();
+
+   req = RING_GET_REQUEST(>ring, req_id);
+   req->req_id = req_id;
+   req->cmd = PVCALLS_ACCEPT;
+   req->u.accept.id = (uint64_t) sock;
+   req->u.accept.ref = map2->active.ref;
+   req->u.accept.id_new = (uint64_t) newsock;
+   req->u.accept.evtchn = evtchn;
+
+   list_add_tail(>list, >socket_mappings);
+   WRITE_ONCE(newsock->sk->sk_send_head, (void *)map2);
+   map2->sock = newsock;
+
+   bedata->ring.req_prod_pvt++;
+   RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(>ring, notify);
+   spin_unlock(>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);
+
+   clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)>passive.flags);
+   wake_up(>passive.inflight_accept_req);
+
+   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 aa8fe10..ab4f1da 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -10,5 +10,8 @@ int pvcalls_front_bind(struct socket *sock,
   struct sockaddr *addr,
   int addr_len);
 int pvcalls_front_listen(struct socket *sock, int backlog);
+int pvcalls_front_accept(struct socket *sock,
+struct socket *newsock,
+int flags);
 
 #endif
-- 
1.9.1