[RFC PATCH 02/13] xen-netback: xenbus feature persistent support
From: Joao Martins <hidden>
Date: 2015-05-12 17:18:26
Also in:
xen-devel
Subsystem:
networking drivers, the rest, xen network backend driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Wei Liu, Paul Durrant
Checks for "feature-persistent" that indicates persistent grants support. Adds max_persistent_grants module param that specifies the max number of persistent grants, which if set to zero disables persistent grants. Signed-off-by: Joao Martins <redacted> --- drivers/net/xen-netback/common.h | 1 + drivers/net/xen-netback/netback.c | 5 +++++ drivers/net/xen-netback/xenbus.c | 13 +++++++++++++ 3 files changed, 19 insertions(+)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index dd02386..e70ace7 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h@@ -378,6 +378,7 @@ extern bool separate_tx_rx_irq; extern unsigned int rx_drain_timeout_msecs; extern unsigned int rx_stall_timeout_msecs; extern unsigned int xenvif_max_queues; +extern unsigned int xenvif_max_pgrants; #ifdef CONFIG_DEBUG_FS extern struct dentry *xen_netback_dbg_root;
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 8df0a73..332e489 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c@@ -72,6 +72,11 @@ module_param_named(max_queues, xenvif_max_queues, uint, 0644); MODULE_PARM_DESC(max_queues, "Maximum number of queues per virtual interface"); +unsigned int xenvif_max_pgrants = XEN_NETIF_RX_RING_SIZE; +module_param_named(max_persistent_grants, xenvif_max_pgrants, int, 0644); +MODULE_PARM_DESC(max_persistent_grants, + "Maximum number of grants to map persistently"); + /* * This is the maximum slots a skb can have. If a guest sends a skb * which exceeds this limit it is considered malicious.
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 3d8dbf5..766f7e5 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c@@ -331,6 +331,14 @@ static int netback_probe(struct xenbus_device *dev, goto fail; } + /* Persistent grants support. This is an optional feature. */ + err = xenbus_printf(XBT_NIL, dev->nodename, + "feature-persistent", "%d", xenvif_max_pgrants > 0); + if (err) { + message = "writing feature-persistent"; + goto abort_transaction; + } + /* * Split event channels support, this is optional so it is not * put inside the above loop.
@@ -961,6 +969,11 @@ static int read_xenbus_vif_flags(struct backend_info *be) val = 0; vif->can_sg = !!val; + if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-persistent", + "%d", &val) < 0) + val = 0; + vif->persistent_grants = (xenvif_max_pgrants && !!val); + vif->gso_mask = 0; vif->gso_prefix_mask = 0;
--
2.1.3