xen-netback: Add support for multiple queues

Builds on the refactoring of the previous patch to implement multiple
queues between xen-netfront and xen-netback.

Writes the maximum supported number of queues into XenStore, and reads
the values written by the frontend to determine how many queues to use.

Ring references and event channels are read from XenStore on a per-queue
basis and rings are connected accordingly.

Also adds code to handle the cleanup of any already initialised queues
if the initialisation of a subsequent queue fails.

Signed-off-by: Andrew J. Bennieston <andrew.bennieston@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index b6885cfcc7df..4dd7c4a1923b 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -237,6 +237,7 @@ struct xenvif *xenvif_alloc(struct device *parent,
                             unsigned int handle);
 
 int xenvif_init_queue(struct xenvif_queue *queue);
+void xenvif_deinit_queue(struct xenvif_queue *queue);
 
 int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
                    unsigned long rx_ring_ref, unsigned int tx_evtchn,
@@ -299,5 +300,6 @@ extern bool separate_tx_rx_irq;
 
 extern unsigned int rx_drain_timeout_msecs;
 extern unsigned int rx_drain_timeout_jiffies;
+extern unsigned int xenvif_max_queues;
 
 #endif /* __XEN_NETBACK__COMMON_H__ */