[PATCH v3 14/21] xen/netfront: use xenbus_setup_ring() and xenbus_teardown_ring()

Juergen Gross
2022-05-05T08:18:14Z

Simplify netfront's ring creation and removal via xenbus_setup_ring()
and xenbus_teardown_ring().

Signed-off-by: Juergen Gross <jgross@suse.com>
---
drivers/net/xen-netfront.c | 53 +++++++++-----------------------------
1 file changed, 12 insertions(+), 41 deletions(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 966bee2a6902..65ab907aca5a 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1921,8 +1921,7 @@ static int setup_netfront(struct xenbus_device *dev,
struct netfront_queue *queue, unsigned int feature_split_evtchn)
{
struct xen_netif_tx_sring *txs;
- struct xen_netif_rx_sring *rxs = NULL;
- grant_ref_t gref;
+ struct xen_netif_rx_sring *rxs;
int err;

queue->tx_ring_ref = INVALID_GRANT_REF;
@@ -1930,33 +1929,19 @@ static int setup_netfront(struct xenbus_device *dev,
queue->rx.sring = NULL;
queue->tx.sring = NULL;

- txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
- if (!txs) {
- err = -ENOMEM;
- xenbus_dev_fatal(dev, err, "allocating tx ring page");
+ err = xenbus_setup_ring(dev, GFP_NOIO | __GFP_HIGH, (void **)&txs,
+ 1, &queue->tx_ring_ref);
+ if (err)
goto fail;
- }
- SHARED_RING_INIT(txs);
- FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);

- err = xenbus_grant_ring(dev, txs, 1, &gref);
- if (err < 0)
- goto fail;
- queue->tx_ring_ref = gref;
+ XEN_FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);

- rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
- if (!rxs) {
- err = -ENOMEM;
- xenbus_dev_fatal(dev, err, "allocating rx ring page");
+ err = xenbus_setup_ring(dev, GFP_NOIO | __GFP_HIGH, (void **)&rxs,
+ 1, &queue->rx_ring_ref);
+ if (err)
goto fail;
- }
- SHARED_RING_INIT(rxs);
- FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);

- err = xenbus_grant_ring(dev, rxs, 1, &gref);
- if (err < 0)
- goto fail;
- queue->rx_ring_ref = gref;
+ XEN_FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);

if (feature_split_evtchn)
err = setup_netfront_split(queue);
@@ -1972,24 +1957,10 @@ static int setup_netfront(struct xenbus_device *dev,

return 0;

- /* If we fail to setup netfront, it is safe to just revoke access to
- * granted pages because backend is not accessing it at this point.
- */
fail:
- if (queue->rx_ring_ref != INVALID_GRANT_REF) {
- gnttab_end_foreign_access(queue->rx_ring_ref,
- (unsigned long)rxs);
- queue->rx_ring_ref = INVALID_GRANT_REF;
- } else {
- free_page((unsigned long)rxs);
- }
- if (queue->tx_ring_ref != INVALID_GRANT_REF) {
- gnttab_end_foreign_access(queue->tx_ring_ref,
- (unsigned long)txs);
- queue->tx_ring_ref = INVALID_GRANT_REF;
- } else {
- free_page((unsigned long)txs);
- }
+ xenbus_teardown_ring((void **)&queue->rx.sring, 1, &queue->rx_ring_ref);
+ xenbus_teardown_ring((void **)&queue->tx.sring, 1, &queue->tx_ring_ref);
+
return err;
}

--
2.35.3