Backend net driver acceleration
Signed-off-by: Kieran Mansley <kmansley@xxxxxxxxxxxxxx>
diff -r 30c836e0575e drivers/xen/netback/Makefile
--- a/drivers/xen/netback/Makefile Fri Jun 15 15:35:17 2007 +0100
+++ b/drivers/xen/netback/Makefile Fri Jun 15 15:37:41 2007 +0100
@@ -1,5 +1,5 @@ obj-$(CONFIG_XEN_NETDEV_BACKEND) := netb
obj-$(CONFIG_XEN_NETDEV_BACKEND) := netbk.o
obj-$(CONFIG_XEN_NETDEV_LOOPBACK) += netloop.o
-netbk-y := netback.o xenbus.o interface.o
+netbk-y := netback.o xenbus.o interface.o accel.o
netloop-y := loopback.o
diff -r 30c836e0575e drivers/xen/netback/accel.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/netback/accel.c Wed Jun 20 14:58:09 2007 +0100
@@ -0,0 +1,207 @@
+/******************************************************************************
+ * drivers/xen/netback/accel.c
+ *
+ * Interface between backend virtual network device and accelerated plugin.
+ *
+ * Copyright (C) 2007 Solarflare Communications, Inc
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/list.h>
+#include <asm/atomic.h>
+#include <xen/xenbus.h>
+
+#include "common.h"
+
+#if 0
+#undef DPRINTK
+#define DPRINTK(fmt, args...) \
+ printk("netback/accel (%s:%d) " fmt ".\n", __FUNCTION__, __LINE__,
##args)
+#endif
+
+/*
+ * A list of available netback accelerator plugin modules (each list
+ * entry is of type struct netback_accelerator)
+ */
+static struct list_head accelerators_list;
+/* Lock used to protect access to accelerators_list */
+static spinlock_t accelerators_lock;
+
+/*
+ * Compare a backend to an accelerator, and decide if they are
+ * compatible (i.e. if the accelerator should be used by the
+ * backend)
+ */
+static int match_accelerator(struct backend_info *be,
+ struct netback_accelerator *accelerator)
+{
+ /*
+ * This could do with being more sophisticated. For example,
+ * determine which hardware is being used by each backend from
+ * the bridge and network topology of the domain
+ */
+ return be->accelerator == NULL;
+}
+
+/*
+ * Notify all suitable backends that a new accelerator is available
+ * and connected. This will also notify the accelerator plugin module
+ * that it is being used for a device through the probe hook.
+ */
+static int netback_accelerator_tell_backend(struct device *dev, void *arg)
+{
+ struct netback_accelerator *accelerator =
+ (struct netback_accelerator *)arg;
+ struct xenbus_device *xendev = to_xenbus_device(dev);
+
+ if (!strcmp("vif", xendev->devicetype)) {
+ struct backend_info *be = xendev->dev.driver_data;
+
+ if (match_accelerator(be, accelerator)) {
+ be->accelerator = accelerator;
+ atomic_inc(&be->accelerator->use_count);
+ be->accelerator->hooks->probe(xendev);
+ }
+ }
+ return 0;
+}
+
+
+/*
+ * Entry point for an netback accelerator plugin module. Called to
+ * advertise its presence, and connect to any suitable backends.
+ */
+void netback_connect_accelerator(int id, const char *frontend,
+ struct netback_accel_hooks *hooks)
+{
+ struct netback_accelerator *new_accelerator =
+ kmalloc(sizeof(struct netback_accelerator), GFP_KERNEL);
+ unsigned frontend_len, flags;
+
+ if (!new_accelerator) {
+ DPRINTK("%s: failed to allocate memory for accelerator\n",
+ __FUNCTION__);
+ return;
+ }
+
+ new_accelerator->id = id;
+
+ frontend_len = strlen(frontend)+1;
+ new_accelerator->frontend = kmalloc(frontend_len, GFP_KERNEL);
+ if (!new_accelerator->frontend) {
+ DPRINTK("%s: failed to allocate memory for frontend string\n",
+ __FUNCTION__);
+ kfree(new_accelerator);
+ return;
+ }
+ strlcpy(new_accelerator->frontend, frontend, frontend_len);
+
+ new_accelerator->hooks = hooks;
+
+ atomic_set(&new_accelerator->use_count, 0);
+
+ spin_lock_irqsave(&accelerators_lock, flags);
+ list_add(&new_accelerator->link, &accelerators_list);
+ spin_unlock_irqrestore(&accelerators_lock, flags);
+
+ /* tell existing backends about new plugin */
+ xenbus_for_each_backend(new_accelerator,
+ netback_accelerator_tell_backend);
+
+}
+EXPORT_SYMBOL_GPL(netback_connect_accelerator);
+
+
+/*
+ * Disconnect an accerator plugin module that has previously been
+ * connected.
+ *
+ * This should only be allowed when there are no remaining users -
+ * i.e. it is not necessary to go through and clear all the hooks, as
+ * they should have already been removed. This is enforced through a
+ * usage count and BUG_ON(use!=0), but should be made more user-friendly
+ */
+void netback_disconnect_accelerator(int id, const char *frontend)
+{
+ struct netback_accelerator *accelerator, *next;
+ unsigned flags;
+
+ spin_lock_irqsave(&accelerators_lock, flags);
+ list_for_each_entry_safe(accelerator, next, &accelerators_list, link) {
+ if (strcmp(frontend, accelerator->frontend)) {
+ BUG_ON(atomic_read(&accelerator->use_count) != 0);
+ list_del(&accelerator->link);
+ spin_unlock_irqrestore(&accelerators_lock, flags);
+ kfree(accelerator->frontend);
+ kfree(accelerator);
+ return;
+ }
+ }
+ spin_unlock_irqrestore(&accelerators_lock, flags);
+}
+EXPORT_SYMBOL_GPL(netback_disconnect_accelerator);
+
+
+void netback_probe_accelerators(struct backend_info *be,
+ struct xenbus_device *dev)
+{
+ struct netback_accelerator *accelerator;
+ unsigned flags;
+
+ /*
+ * Check list of accelerators to see if any is suitable, and
+ * use it if it is.
+ */
+ spin_lock_irqsave(&accelerators_lock, flags);
+ list_for_each_entry(accelerator, &accelerators_list, link) {
+ if (match_accelerator(be, accelerator)) {
+ be->accelerator = accelerator;
+ atomic_inc(&be->accelerator->use_count);
+ be->accelerator->hooks->probe(dev);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&accelerators_lock, flags);
+}
+
+
+void netback_remove_accelerators(struct backend_info *be,
+ struct xenbus_device *dev)
+{
+ /* Notify the accelerator (if any) of this device's removal */
+ if ( be->accelerator ) {
+ be->accelerator->hooks->remove(dev);
+ atomic_dec(&be->accelerator->use_count);
+ }
+ be->accelerator = NULL;
+}
+
+
+void netif_accel_init(void)
+{
+ INIT_LIST_HEAD(&accelerators_list);
+ spin_lock_init(&accelerators_lock);
+}
diff -r 30c836e0575e drivers/xen/netback/common.h
--- a/drivers/xen/netback/common.h Fri Jun 15 15:35:17 2007 +0100
+++ b/drivers/xen/netback/common.h Mon Jun 18 09:30:21 2007 +0100
@@ -45,6 +45,7 @@
#include <xen/interface/grant_table.h>
#include <xen/gnttab.h>
#include <xen/driver_util.h>
+#include <xen/xenbus.h>
#define DPRINTK(_f, _a...) \
pr_debug("(file=%s, line=%d) " _f, \
@@ -122,6 +123,49 @@ enum {
extern int netbk_copy_skb_mode;
+/* Function pointers into netback accelerator plugin modules */
+struct netback_accel_hooks {
+ int (*probe)(struct xenbus_device *dev);
+ int (*remove)(struct xenbus_device *dev);
+};
+
+/* Structure to track the state of a netback accelerator plugin */
+struct netback_accelerator {
+ struct list_head link;
+ int id;
+ char *frontend;
+ atomic_t use_count;
+ struct netback_accel_hooks *hooks;
+};
+
+struct backend_info {
+ struct xenbus_device *dev;
+ netif_t *netif;
+ enum xenbus_state frontend_state;
+
+ /* State relating to the netback accelerator */
+ void *netback_accel_priv;
+ /* The accelerator that this backend is currently using */
+ struct netback_accelerator *accelerator;
+};
+
+/* Connect an accelerator plugin module to netback */
+extern void netback_connect_accelerator(int id, const char *frontend,
+ struct netback_accel_hooks *hooks);
+/* Disconnect a previously connected accelerator pluging module */
+extern void netback_disconnect_accelerator(int id, const char *frontend);
+
+
+extern
+void netback_probe_accelerators(struct backend_info *be,
+ struct xenbus_device *dev);
+extern
+void netback_remove_accelerators(struct backend_info *be,
+ struct xenbus_device *dev);
+extern
+void netif_accel_init(void);
+
+
#define NET_TX_RING_SIZE __RING_SIZE((netif_tx_sring_t *)0, PAGE_SIZE)
#define NET_RX_RING_SIZE __RING_SIZE((netif_rx_sring_t *)0, PAGE_SIZE)
diff -r 30c836e0575e drivers/xen/netback/netback.c
--- a/drivers/xen/netback/netback.c Fri Jun 15 15:35:17 2007 +0100
+++ b/drivers/xen/netback/netback.c Mon Jun 18 09:30:21 2007 +0100
@@ -1587,6 +1587,8 @@ static int __init netback_init(void)
netbk_copy_skb_mode = NETBK_DELAYED_COPY_SKB;
}
+ netif_accel_init();
+
netif_xenbus_init();
#ifdef NETBE_DEBUG_INTERRUPT
diff -r 30c836e0575e drivers/xen/netback/xenbus.c
--- a/drivers/xen/netback/xenbus.c Fri Jun 15 15:35:17 2007 +0100
+++ b/drivers/xen/netback/xenbus.c Wed Jun 20 14:58:20 2007 +0100
@@ -28,11 +28,6 @@
printk("netback/xenbus (%s:%d) " fmt ".\n", __FUNCTION__, __LINE__, ##args)
#endif
-struct backend_info {
- struct xenbus_device *dev;
- netif_t *netif;
- enum xenbus_state frontend_state;
-};
static int connect_rings(struct backend_info *);
static void connect(struct backend_info *);
@@ -41,6 +36,8 @@ static int netback_remove(struct xenbus_
static int netback_remove(struct xenbus_device *dev)
{
struct backend_info *be = dev->dev.driver_data;
+
+ netback_remove_accelerators(be, dev);
if (be->netif) {
netif_disconnect(be->netif);
@@ -125,6 +122,8 @@ static int netback_probe(struct xenbus_d
goto fail;
}
+ netback_probe_accelerators(be, dev);
+
err = xenbus_switch_state(dev, XenbusStateInitWait);
if (err)
goto fail;
backend_accel
Description: Text document
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