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Date: Tue, 12 May 2015 19:18:34 +0200
From: Joao Martins <joao.martins@...lab.eu>
To: <xen-devel@...ts.xenproject.org>, <netdev@...r.kernel.org>
CC: <wei.liu2@...rix.com>, <ian.campbell@...rix.com>,
<david.vrabel@...rix.com>, <boris.ostrovsky@...cle.com>,
<konrad.wilk@...cle.com>, Joao Martins <joao.martins@...lab.eu>
Subject: [RFC PATCH 10/13] xen-netfront: refactor claim/release grant
Refactors how grants are claimed/released/revoked by moving that code
into claim_grant and release_grant helpers routines that can be shared
in both TX/RX path.
Signed-off-by: Joao Martins <joao.martins@...lab.eu>
---
drivers/net/xen-netfront.c | 87 ++++++++++++++++++++++++++++++----------------
1 file changed, 58 insertions(+), 29 deletions(-)
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 8f49ed4..99c17c9 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -256,6 +256,43 @@ static void xennet_maybe_wake_tx(struct netfront_queue *queue)
netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
}
+static grant_ref_t claim_grant(struct page *page,
+ grant_ref_t *gref_head,
+ int otherend_id,
+ int flags)
+{
+ grant_ref_t ref;
+ unsigned long mfn;
+
+ ref = gnttab_claim_grant_reference(gref_head);
+ BUG_ON(ref < 0);
+
+ mfn = pfn_to_mfn(page_to_pfn(page));
+ gnttab_grant_foreign_access_ref(
+ ref, otherend_id, mfn, flags);
+
+ return ref;
+}
+
+static void release_grant(grant_ref_t ref,
+ grant_ref_t *gref_head,
+ int otherend_id,
+ int flags)
+{
+ int ret;
+
+ if (unlikely(gnttab_query_foreign_access(
+ ref) != 0)) {
+ pr_alert("%s: warning -- grant still in use by backend domain\n",
+ __func__);
+ BUG();
+ }
+
+ ret = gnttab_end_foreign_access_ref(ref, flags);
+ BUG_ON(!ret);
+
+ gnttab_release_grant_reference(gref_head, ref);
+}
static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
{
@@ -297,7 +334,7 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
struct sk_buff *skb;
unsigned short id;
grant_ref_t ref;
- unsigned long pfn;
+ struct page *page;
struct xen_netif_rx_request *req;
skb = xennet_alloc_one_rx_buffer(queue);
@@ -309,17 +346,15 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
BUG_ON(queue->rx_skbs[id]);
queue->rx_skbs[id] = skb;
- ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
- BUG_ON((signed short)ref < 0);
- queue->grant_rx[id].ref = ref;
+ page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
+ ref = claim_grant(page,
+ &queue->gref_rx_head,
+ queue->info->xbdev->otherend_id,
+ 0);
- pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
+ queue->grant_rx[id].ref = ref;
req = RING_GET_REQUEST(&queue->rx, req_prod);
- gnttab_grant_foreign_access_ref(ref,
- queue->info->xbdev->otherend_id,
- pfn_to_mfn(pfn),
- 0);
req->id = id;
req->gref = ref;
@@ -387,16 +422,12 @@ static void xennet_tx_buf_gc(struct netfront_queue *queue)
id = txrsp->id;
skb = queue->tx_skbs[id].skb;
- if (unlikely(gnttab_query_foreign_access(
- queue->grant_tx[id].ref) != 0)) {
- pr_alert("%s: warning -- grant still in use by backend domain\n",
- __func__);
- BUG();
- }
- gnttab_end_foreign_access_ref(
- queue->grant_tx[id].ref, GNTMAP_readonly);
- gnttab_release_grant_reference(
- &queue->gref_tx_head, queue->grant_tx[id].ref);
+
+ release_grant(queue->grant_tx[id].ref,
+ &queue->gref_tx_head,
+ queue->info->xbdev->otherend_id,
+ GNTMAP_readonly);
+
queue->grant_tx[id].ref = GRANT_INVALID_REF;
queue->grant_tx[id].page = NULL;
add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
@@ -433,11 +464,10 @@ static struct xen_netif_tx_request *xennet_make_one_txreq(
id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
- ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
- BUG_ON((signed short)ref < 0);
-
- gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
- page_to_mfn(page), GNTMAP_readonly);
+ ref = claim_grant(page,
+ &queue->gref_tx_head,
+ queue->info->xbdev->otherend_id,
+ GNTMAP_readonly);
queue->tx_skbs[id].skb = skb;
queue->grant_tx[id].page = page;
@@ -727,7 +757,6 @@ static int xennet_get_responses(struct netfront_queue *queue,
int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
int slots = 1;
int err = 0;
- unsigned long ret;
if (rx->flags & XEN_NETRXF_extra_info) {
err = xennet_get_extras(queue, extras, rp);
@@ -758,10 +787,10 @@ static int xennet_get_responses(struct netfront_queue *queue,
goto next;
}
- ret = gnttab_end_foreign_access_ref(ref, 0);
- BUG_ON(!ret);
-
- gnttab_release_grant_reference(&queue->gref_rx_head, ref);
+ release_grant(ref,
+ &queue->gref_rx_head,
+ queue->info->xbdev->otherend_id,
+ 0);
__skb_queue_tail(list, skb);
--
2.1.3
--
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