[PATCH 0/5] pvcalls fixes

[PATCH 0/5] pvcalls fixes

[Stefano Stabellini]

Hi all,

This series is a collection of small pvcalls fixes.

Cheers,

Stefano


Stefano Stabellini (5):
      pvcalls-front: read all data before closing the connection
      pvcalls-front: don't try to free unallocated rings
      pvcalls-front: properly allocate sk
      pvcalls-front: don't return error when the ring is full
      pvcalls-back: set -ENOTCONN in pvcalls_conn_back_read

 drivers/xen/pvcalls-back.c  |  7 ++++---
 drivers/xen/pvcalls-front.c | 20 +++++++++++++-------
 2 files changed, 17 insertions(+), 10 deletions(-)

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

[PATCH 1/5] pvcalls-front: read all data before closing the connection

[Stefano Stabellini]

When a connection is closing in_error is set to ENOTCONN. There could
still be outstanding data on the ring left by the backend. Before
closing the connection on the frontend side, drain the ring.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
---
 drivers/xen/pvcalls-front.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 77224d8..e5d95aa 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -560,15 +560,13 @@ static int __read_ring(struct pvcalls_data_intf *intf,
 	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;
+		return error ?: size;
 
 	if (len > size)
 		len = size;
-- 
1.9.1


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

[PATCH 2/5] pvcalls-front: don't try to free unallocated rings

[Stefano Stabellini]

inflight_req_id is 0 when initialized. If inflight_req_id is 0, there is
no accept_map to free. Fix the check in pvcalls_front_release.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
---
 drivers/xen/pvcalls-front.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index e5d95aa..4f3d664 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -1030,8 +1030,8 @@ int pvcalls_front_release(struct socket *sock)
 		spin_lock(&bedata->socket_lock);
 		list_del(&map->list);
 		spin_unlock(&bedata->socket_lock);
-		if (READ_ONCE(map->passive.inflight_req_id) !=
-		    PVCALLS_INVALID_ID) {
+		if (READ_ONCE(map->passive.inflight_req_id) != PVCALLS_INVALID_ID &&
+			READ_ONCE(map->passive.inflight_req_id) != 0) {
 			pvcalls_front_free_map(bedata,
 					       map->passive.accept_map);
 		}
-- 
1.9.1


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

[PATCH 3/5] pvcalls-front: properly allocate sk

[Stefano Stabellini]

Don't use kzalloc: it ends up leaving sk->sk_prot not properly
initialized. Use sk_alloc instead and define our own trivial struct
proto.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
---
 drivers/xen/pvcalls-front.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 4f3d664..0158858 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -31,6 +31,12 @@
 #define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE)
 #define PVCALLS_FRONT_MAX_SPIN 5000
 
+static struct proto pvcalls_proto = {
+	.name	= "PVCalls",
+	.owner	= THIS_MODULE,
+	.obj_size = sizeof(struct sock),
+};
+
 struct pvcalls_bedata {
 	struct xen_pvcalls_front_ring ring;
 	grant_ref_t ref;
@@ -837,7 +843,7 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
 
 received:
 	map2->sock = newsock;
-	newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL);
+	newsock->sk = sk_alloc(sock_net(sock->sk), PF_INET, GFP_KERNEL, &pvcalls_proto, false);
 	if (!newsock->sk) {
 		bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
 		map->passive.inflight_req_id = PVCALLS_INVALID_ID;
-- 
1.9.1


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

[PATCH 4/5] pvcalls-front: don't return error when the ring is full

[Stefano Stabellini]

When the ring is full, size == array_size. It is not an error condition,
so simply return 0 instead of an error.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
---
 drivers/xen/pvcalls-front.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 0158858..1a893a1 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -475,8 +475,10 @@ static int __write_ring(struct pvcalls_data_intf *intf,
 	virt_mb();
 
 	size = pvcalls_queued(prod, cons, array_size);
-	if (size >= array_size)
+	if (size > array_size)
 		return -EINVAL;
+	if (size == array_size)
+		return 0;
 	if (len > array_size - size)
 		len = array_size - size;
 
-- 
1.9.1


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

[PATCH 5/5] pvcalls-back: set -ENOTCONN in pvcalls_conn_back_read

[Stefano Stabellini]

When a connection is closing we receive on pvcalls_sk_state_change
notification. Instead of setting the connection as closed immediately
(-ENOTCONN), let's read one more time from it: pvcalls_conn_back_read
will set the connection as closed when necessary.

That way, we avoid races between pvcalls_sk_state_change and
pvcalls_back_ioworker.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
---
 drivers/xen/pvcalls-back.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 2e5d845..71b6287 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -160,9 +160,10 @@ static void pvcalls_conn_back_read(void *opaque)
 
 	/* write the data, then modify the indexes */
 	virt_wmb();
-	if (ret < 0)
+	if (ret < 0) {
+		atomic_set(&map->read, 0);
 		intf->in_error = ret;
-	else
+	} else
 		intf->in_prod = prod + ret;
 	/* update the indexes, then notify the other end */
 	virt_wmb();
@@ -288,7 +289,7 @@ static void pvcalls_sk_state_change(struct sock *sock)
 		return;
 
 	intf = map->ring;
-	intf->in_error = -ENOTCONN;
+	atomic_inc(&map->read);
 	notify_remote_via_irq(map->irq);
 }
 
-- 
1.9.1


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

Re: [PATCH 0/5] pvcalls fixes

[Boris Ostrovsky]

On 12/21/18 6:06 PM, Stefano Stabellini wrote:
> Hi all,
>
> This series is a collection of small pvcalls fixes.
>
> Cheers,
>
> Stefano
>
>
> Stefano Stabellini (5):
>       pvcalls-front: read all data before closing the connection
>       pvcalls-front: don't try to free unallocated rings
>       pvcalls-front: properly allocate sk
>       pvcalls-front: don't return error when the ring is full
>       pvcalls-back: set -ENOTCONN in pvcalls_conn_back_read
>
>  drivers/xen/pvcalls-back.c  |  7 ++++---
>  drivers/xen/pvcalls-front.c | 20 +++++++++++++-------
>  2 files changed, 17 insertions(+), 10 deletions(-)


Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Applied to for-linus-21.



_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel