[Xen-devel] [PATCH net] xen-netback: fix abuse of napi budget

[Paul Durrant <paul.durrant@xxxxxxxxxx>]

netback seemed to be somewhat confused about the napi budget parameter and
basically ignored it. This patch fixes that, properly limiting the work done
in each poll.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
---
 drivers/net/xen-netback/netback.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/xen-netback/netback.c 
b/drivers/net/xen-netback/netback.c
index 43341b8..83b4e5b 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1351,14 +1351,15 @@ static bool tx_credit_exceeded(struct xenvif *vif, 
unsigned size)
        return false;
 }
 
-static unsigned xenvif_tx_build_gops(struct xenvif *vif)
+static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget)
 {
        struct gnttab_copy *gop = vif->tx_copy_ops, *request_gop;
        struct sk_buff *skb;
        int ret;
 
        while ((nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
-               < MAX_PENDING_REQS)) {
+               < MAX_PENDING_REQS) &&
+              (skb_queue_len(&vif->tx_queue) < budget)) {
                struct xen_netif_tx_request txreq;
                struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
                struct page *page;
@@ -1520,14 +1521,13 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif)
 }
 
 
-static int xenvif_tx_submit(struct xenvif *vif, int budget)
+static int xenvif_tx_submit(struct xenvif *vif)
 {
        struct gnttab_copy *gop = vif->tx_copy_ops;
        struct sk_buff *skb;
        int work_done = 0;
 
-       while (work_done < budget &&
-              (skb = __skb_dequeue(&vif->tx_queue)) != NULL) {
+       while ((skb = __skb_dequeue(&vif->tx_queue)) != NULL) {
                struct xen_netif_tx_request *txp;
                u16 pending_idx;
                unsigned data_len;
@@ -1602,14 +1602,14 @@ int xenvif_tx_action(struct xenvif *vif, int budget)
        if (unlikely(!tx_work_todo(vif)))
                return 0;
 
-       nr_gops = xenvif_tx_build_gops(vif);
+       nr_gops = xenvif_tx_build_gops(vif, budget);
 
        if (nr_gops == 0)
                return 0;
 
        gnttab_batch_copy(vif->tx_copy_ops, nr_gops);
 
-       work_done = xenvif_tx_submit(vif, nr_gops);
+       work_done = xenvif_tx_submit(vif);
 
        return work_done;
 }
-- 
1.7.10.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel