[PATCH net-next v7 2/9] xen-netback: Minor refactoring of netback code

From: Zoltan Kiss
Date: Thu Mar 06 2014 - 16:49:01 EST


This patch contains a few bits of refactoring before introducing the grant
mapping changes:
- introducing xenvif_tx_pending_slots_available(), as this is used several
times, and will be used more often
- rename the thread to vifX.Y-guest-rx, to signify it does RX work from the
guest point of view

Signed-off-by: Zoltan Kiss <zoltan.kiss@xxxxxxxxxx>
---

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index ae413a2..9d35845 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -108,6 +108,15 @@ struct xenvif_rx_meta {
*/
#define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)

+#define NETBACK_INVALID_HANDLE -1
+
+/* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
+ * the maximum slots a valid packet can use. Now this value is defined
+ * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
+ * all backend.
+ */
+#define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
+
struct xenvif {
/* Unique identifier for this interface. */
domid_t domid;
@@ -216,7 +225,7 @@ void xenvif_carrier_off(struct xenvif *vif);

int xenvif_tx_action(struct xenvif *vif, int budget);

-int xenvif_kthread(void *data);
+int xenvif_kthread_guest_rx(void *data);
void xenvif_kick_thread(struct xenvif *vif);

/* Determine whether the needed number of slots (req) are available,
@@ -226,6 +235,18 @@ bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);

void xenvif_stop_queue(struct xenvif *vif);

+static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
+{
+ return MAX_PENDING_REQS -
+ vif->pending_prod + vif->pending_cons;
+}
+
+static inline bool xenvif_tx_pending_slots_available(struct xenvif *vif)
+{
+ return nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
+ < MAX_PENDING_REQS;
+}
+
extern bool separate_tx_rx_irq;

#endif /* __XEN_NETBACK__COMMON_H__ */
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 7669d49..bc32627 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -421,8 +421,8 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
disable_irq(vif->rx_irq);
}

- task = kthread_create(xenvif_kthread,
- (void *)vif, "%s", vif->dev->name);
+ task = kthread_create(xenvif_kthread_guest_rx,
+ (void *)vif, "%s-guest-rx", vif->dev->name);
if (IS_ERR(task)) {
pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
err = PTR_ERR(task);
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 43ae4ba..715d810 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -63,14 +63,6 @@ static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
module_param(fatal_skb_slots, uint, 0444);

/*
- * To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
- * the maximum slots a valid packet can use. Now this value is defined
- * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
- * all backend.
- */
-#define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
-
-/*
* If head != INVALID_PENDING_RING_IDX, it means this tx request is head of
* one or more merged tx requests, otherwise it is the continuation of
* previous tx request.
@@ -131,12 +123,6 @@ static inline pending_ring_idx_t pending_index(unsigned i)
return i & (MAX_PENDING_REQS-1);
}

-static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
-{
- return MAX_PENDING_REQS -
- vif->pending_prod + vif->pending_cons;
-}
-
bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed)
{
RING_IDX prod, cons;
@@ -1116,8 +1102,7 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget)
struct sk_buff *skb;
int ret;

- while ((nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
- < MAX_PENDING_REQS) &&
+ while (xenvif_tx_pending_slots_available(vif) &&
(skb_queue_len(&vif->tx_queue) < budget)) {
struct xen_netif_tx_request txreq;
struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
@@ -1487,8 +1472,7 @@ static inline int tx_work_todo(struct xenvif *vif)
{

if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->tx)) &&
- (nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
- < MAX_PENDING_REQS))
+ xenvif_tx_pending_slots_available(vif))
return 1;

return 0;
@@ -1551,7 +1535,7 @@ static void xenvif_start_queue(struct xenvif *vif)
netif_wake_queue(vif->dev);
}

-int xenvif_kthread(void *data)
+int xenvif_kthread_guest_rx(void *data)
{
struct xenvif *vif = data;
struct sk_buff *skb;
--
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