[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [linux-2.6.18-xen] net accel: Allow network accelerators to deal with hot-plug/unplug on
# HG changeset patch # User Keir Fraser <keir.fraser@xxxxxxxxxx> # Date 1198075661 0 # Node ID 41e34ec8d24908a77d514415a26e3304c914cc98 # Parent 7db9c653b4f97250e38744a21df099f7ffc0e4a4 net accel: Allow network accelerators to deal with hot-plug/unplug on physical devices. Add watch for acceleration configuration in frontend. Signed-off-by: Kieran Mansley <kmansley@xxxxxxxxxxxxxx> --- drivers/xen/netback/accel.c | 116 ++++++++-------- drivers/xen/netback/common.h | 2 drivers/xen/netfront/accel.c | 290 ++++++++++++++++++++++++++-------------- drivers/xen/netfront/netfront.c | 20 -- drivers/xen/netfront/netfront.h | 26 +-- 5 files changed, 271 insertions(+), 183 deletions(-) diff -r 7db9c653b4f9 -r 41e34ec8d249 drivers/xen/netback/accel.c --- a/drivers/xen/netback/accel.c Mon Dec 17 13:41:07 2007 -0700 +++ b/drivers/xen/netback/accel.c Wed Dec 19 14:47:41 2007 +0000 @@ -76,12 +76,27 @@ static int match_accelerator(struct xenb } } -/* - * Notify all suitable backends that a new accelerator is available - * and connected. This will also notify the accelerator plugin module + +static void do_probe(struct backend_info *be, + struct netback_accelerator *accelerator, + struct xenbus_device *xendev) +{ + be->accelerator = accelerator; + atomic_inc(&be->accelerator->use_count); + if (be->accelerator->hooks->probe(xendev) != 0) { + atomic_dec(&be->accelerator->use_count); + module_put(be->accelerator->hooks->owner); + be->accelerator = NULL; + } +} + + +/* + * Notify 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) +static int netback_accelerator_probe_backend(struct device *dev, void *arg) { struct netback_accelerator *accelerator = (struct netback_accelerator *)arg; @@ -90,14 +105,37 @@ static int netback_accelerator_tell_back if (!strcmp("vif", xendev->devicetype)) { struct backend_info *be = xendev->dev.driver_data; - if (match_accelerator(xendev, be, accelerator)) { - be->accelerator = accelerator; - atomic_inc(&be->accelerator->use_count); - be->accelerator->hooks->probe(xendev); - } - } - return 0; -} + if (match_accelerator(xendev, be, accelerator) && + try_module_get(accelerator->hooks->owner)) { + do_probe(be, accelerator, xendev); + } + } + return 0; +} + + +/* + * Notify suitable backends that an accelerator is unavailable. + */ +static int netback_accelerator_remove_backend(struct device *dev, void *arg) +{ + struct xenbus_device *xendev = to_xenbus_device(dev); + struct netback_accelerator *accelerator = + (struct netback_accelerator *)arg; + + if (!strcmp("vif", xendev->devicetype)) { + struct backend_info *be = xendev->dev.driver_data; + + if (be->accelerator == accelerator) { + be->accelerator->hooks->remove(xendev); + atomic_dec(&be->accelerator->use_count); + module_put(be->accelerator->hooks->owner); + be->accelerator = NULL; + } + } + return 0; +} + /* @@ -133,7 +171,6 @@ int netback_connect_accelerator(unsigned return -ENOMEM; } - new_accelerator->id = id; eth_name_len = strlen(eth_name)+1; @@ -152,44 +189,22 @@ int netback_connect_accelerator(unsigned mutex_lock(&accelerators_mutex); list_add(&new_accelerator->link, &accelerators_list); - mutex_unlock(&accelerators_mutex); /* tell existing backends about new plugin */ xenbus_for_each_backend(new_accelerator, - netback_accelerator_tell_backend); + netback_accelerator_probe_backend); + + mutex_unlock(&accelerators_mutex); return 0; } EXPORT_SYMBOL_GPL(netback_connect_accelerator); - - -/* - * Remove the link from backend state to a particular accelerator - */ -static int netback_accelerator_cleanup_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 (be->accelerator == accelerator) - be->accelerator = NULL; - } - return 0; -} /* * Disconnect an accelerator 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 by taking - * a module reference to the plugin while the interfaces are in use */ void netback_disconnect_accelerator(int id, const char *eth_name) { @@ -197,17 +212,14 @@ void netback_disconnect_accelerator(int mutex_lock(&accelerators_mutex); list_for_each_entry_safe(accelerator, next, &accelerators_list, link) { - if (strcmp(eth_name, accelerator->eth_name)) { + if (!strcmp(eth_name, accelerator->eth_name)) { + xenbus_for_each_backend + (accelerator, netback_accelerator_remove_backend); BUG_ON(atomic_read(&accelerator->use_count) != 0); - list_del(&accelerator->link); - mutex_unlock(&accelerators_mutex); - - xenbus_for_each_backend(accelerator, - netback_accelerator_cleanup_backend); - + list_del(&accelerator->link); kfree(accelerator->eth_name); kfree(accelerator); - return; + break; } } mutex_unlock(&accelerators_mutex); @@ -228,9 +240,7 @@ void netback_probe_accelerators(struct b list_for_each_entry(accelerator, &accelerators_list, link) { if (match_accelerator(dev, be, accelerator) && try_module_get(accelerator->hooks->owner)) { - be->accelerator = accelerator; - atomic_inc(&be->accelerator->use_count); - be->accelerator->hooks->probe(dev); + do_probe(be, accelerator, dev); break; } } @@ -241,13 +251,15 @@ void netback_remove_accelerators(struct void netback_remove_accelerators(struct backend_info *be, struct xenbus_device *dev) { + mutex_lock(&accelerators_mutex); /* Notify the accelerator (if any) of this device's removal */ - if (be->accelerator) { + if (be->accelerator != NULL) { be->accelerator->hooks->remove(dev); atomic_dec(&be->accelerator->use_count); module_put(be->accelerator->hooks->owner); - } - be->accelerator = NULL; + be->accelerator = NULL; + } + mutex_unlock(&accelerators_mutex); } diff -r 7db9c653b4f9 -r 41e34ec8d249 drivers/xen/netback/common.h --- a/drivers/xen/netback/common.h Mon Dec 17 13:41:07 2007 -0700 +++ b/drivers/xen/netback/common.h Wed Dec 19 14:47:41 2007 +0000 @@ -150,7 +150,7 @@ struct backend_info { struct netback_accelerator *accelerator; }; -#define NETBACK_ACCEL_VERSION 0x00010000 +#define NETBACK_ACCEL_VERSION 0x00010001 /* * Connect an accelerator plugin module to netback. Returns zero on diff -r 7db9c653b4f9 -r 41e34ec8d249 drivers/xen/netfront/accel.c --- a/drivers/xen/netfront/accel.c Mon Dec 17 13:41:07 2007 -0700 +++ b/drivers/xen/netfront/accel.c Wed Dec 19 14:47:41 2007 +0000 @@ -45,6 +45,12 @@ #define WPRINTK(fmt, args...) \ printk(KERN_WARNING "netfront/accel: " fmt, ##args) +static int netfront_remove_accelerator(struct netfront_info *np, + struct xenbus_device *dev); +static int netfront_load_accelerator(struct netfront_info *np, + struct xenbus_device *dev, + const char *frontend); + /* * List of all netfront accelerator plugin modules available. Each * list entry is of type struct netfront_accelerator. @@ -83,6 +89,120 @@ void netif_exit_accel(void) /* + * Watch the configured accelerator and change plugin if it's modified + */ +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20) +static void accel_watch_work(struct work_struct *context) +#else +static void accel_watch_work(void *context) +#endif +{ +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20) + struct netfront_accel_vif_state *vif_state = + container_of(context, struct netfront_accel_vif_state, + accel_work); +#else + struct netfront_accel_vif_state *vif_state = + (struct netfront_accel_vif_state *)context; +#endif + struct netfront_info *np = vif_state->np; + char *accel_frontend; + int accel_len, rc = -1; + + mutex_lock(&accelerator_mutex); + + accel_frontend = xenbus_read(XBT_NIL, np->xbdev->otherend, + "accel-frontend", &accel_len); + if (IS_ERR(accel_frontend)) { + accel_frontend = NULL; + netfront_remove_accelerator(np, np->xbdev); + } else { + /* If this is the first time, request the accelerator, + otherwise only request one if it has changed */ + if (vif_state->accel_frontend == NULL) { + rc = netfront_load_accelerator(np, np->xbdev, + accel_frontend); + } else { + if (strncmp(vif_state->accel_frontend, accel_frontend, + accel_len)) { + netfront_remove_accelerator(np, np->xbdev); + rc = netfront_load_accelerator(np, np->xbdev, + accel_frontend); + } + } + } + + /* Get rid of previous state and replace with the new name */ + if (vif_state->accel_frontend != NULL) + kfree(vif_state->accel_frontend); + vif_state->accel_frontend = accel_frontend; + + mutex_unlock(&accelerator_mutex); + + if (rc == 0) { + DPRINTK("requesting module %s\n", accel_frontend); + request_module("%s", accel_frontend); + /* + * Module should now call netfront_accelerator_loaded() once + * it's up and running, and we can continue from there + */ + } +} + + +static void accel_watch_changed(struct xenbus_watch *watch, + const char **vec, unsigned int len) +{ + struct netfront_accel_vif_state *vif_state = + container_of(watch, struct netfront_accel_vif_state, + accel_watch); + schedule_work(&vif_state->accel_work); +} + + +void netfront_accelerator_add_watch(struct netfront_info *np) +{ + int err; + + /* Check we're not trying to overwrite an existing watch */ + BUG_ON(np->accel_vif_state.accel_watch.node != NULL); + + /* Get a watch on the accelerator plugin */ + err = xenbus_watch_path2(np->xbdev, np->xbdev->otherend, + "accel-frontend", + &np->accel_vif_state.accel_watch, + accel_watch_changed); + if (err) { + DPRINTK("%s: Failed to register accel watch: %d\n", + __FUNCTION__, err); + np->accel_vif_state.accel_watch.node = NULL; + } +} + + +static +void netfront_accelerator_remove_watch(struct netfront_info *np) +{ + struct netfront_accel_vif_state *vif_state = &np->accel_vif_state; + + /* Get rid of watch on accelerator plugin */ + if (vif_state->accel_watch.node != NULL) { + unregister_xenbus_watch(&vif_state->accel_watch); + kfree(vif_state->accel_watch.node); + vif_state->accel_watch.node = NULL; + + flush_scheduled_work(); + + /* Clean up any state left from watch */ + if (vif_state->accel_frontend != NULL) { + kfree(vif_state->accel_frontend); + vif_state->accel_frontend = NULL; + } + } +} + + +/* * Initialise the accel_vif_state field in the netfront state */ void init_accelerator_vif(struct netfront_info *np, @@ -93,6 +213,13 @@ void init_accelerator_vif(struct netfron /* It's assumed that these things don't change */ np->accel_vif_state.np = np; np->accel_vif_state.dev = dev; + +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20) + INIT_WORK(&np->accel_vif_state.accel_work, accel_watch_work); +#else + INIT_WORK(&np->accel_vif_state.accel_work, accel_watch_work, + &np->accel_vif_state); +#endif } @@ -202,6 +329,7 @@ static void accelerator_probe_new_vif(st struct netfront_accelerator *accelerator) { struct netfront_accel_hooks *hooks; + unsigned long flags; DPRINTK("\n"); @@ -211,32 +339,35 @@ static void accelerator_probe_new_vif(st hooks = accelerator->hooks; if (hooks) { - hooks->new_device(np->netdev, dev); - /* - * Hooks will get linked into vif_state by a future - * call by the accelerator to netfront_accelerator_ready() - */ + if (hooks->new_device(np->netdev, dev) == 0) { + spin_lock_irqsave + (&accelerator->vif_states_lock, flags); + + accelerator_set_vif_state_hooks(&np->accel_vif_state); + + spin_unlock_irqrestore + (&accelerator->vif_states_lock, flags); + } } return; } + /* * Request that a particular netfront accelerator plugin is loaded. * Usually called as a result of the vif configuration specifying - * which one to use. - */ -int netfront_load_accelerator(struct netfront_info *np, - struct xenbus_device *dev, - const char *frontend) + * which one to use. Must be called with accelerator_mutex held + */ +static int netfront_load_accelerator(struct netfront_info *np, + struct xenbus_device *dev, + const char *frontend) { struct netfront_accelerator *accelerator; int rc = 0; unsigned long flags; DPRINTK(" %s\n", frontend); - - mutex_lock(&accelerator_mutex); spin_lock_irqsave(&accelerators_lock, flags); @@ -249,8 +380,6 @@ int netfront_load_accelerator(struct net spin_unlock_irqrestore(&accelerators_lock, flags); accelerator_probe_new_vif(np, dev, accelerator); - - mutex_unlock(&accelerator_mutex); return 0; } } @@ -258,7 +387,6 @@ int netfront_load_accelerator(struct net /* Couldn't find it, so create a new one and load the module */ if ((rc = init_accelerator(frontend, &accelerator, NULL)) < 0) { spin_unlock_irqrestore(&accelerators_lock, flags); - mutex_unlock(&accelerator_mutex); return rc; } @@ -266,18 +394,6 @@ int netfront_load_accelerator(struct net /* Include this frontend device on the accelerator's list */ add_accelerator_vif(accelerator, np); - - mutex_unlock(&accelerator_mutex); - - DPRINTK("requesting module %s\n", frontend); - - /* load module */ - request_module("%s", frontend); - - /* - * Module should now call netfront_accelerator_loaded() once - * it's up and running, and we can continue from there - */ return rc; } @@ -294,6 +410,7 @@ accelerator_probe_vifs(struct netfront_a struct netfront_accel_hooks *hooks) { struct netfront_accel_vif_state *vif_state, *tmp; + unsigned long flags; DPRINTK("%p\n", accelerator); @@ -313,13 +430,15 @@ accelerator_probe_vifs(struct netfront_a link) { struct netfront_info *np = vif_state->np; - hooks->new_device(np->netdev, vif_state->dev); - - /* - * Hooks will get linked into vif_state by a call to - * netfront_accelerator_ready() once accelerator - * plugin is ready for action - */ + if (hooks->new_device(np->netdev, vif_state->dev) == 0) { + spin_lock_irqsave + (&accelerator->vif_states_lock, flags); + + accelerator_set_vif_state_hooks(vif_state); + + spin_unlock_irqrestore + (&accelerator->vif_states_lock, flags); + } } } @@ -385,48 +504,6 @@ EXPORT_SYMBOL_GPL(netfront_accelerator_l /* - * Called by the accelerator module after it has been probed with a - * network device to say that it is ready to start accelerating - * traffic on that device - */ -void netfront_accelerator_ready(const char *frontend, - struct xenbus_device *dev) -{ - struct netfront_accelerator *accelerator; - struct netfront_accel_vif_state *accel_vif_state; - unsigned long flags, flags1; - - DPRINTK("%s %p\n", frontend, dev); - - spin_lock_irqsave(&accelerators_lock, flags); - - list_for_each_entry(accelerator, &accelerators_list, link) { - if (match_accelerator(frontend, accelerator)) { - /* - * Mutex not held so need vif_states_lock for - * list - */ - spin_lock_irqsave - (&accelerator->vif_states_lock, flags1); - - list_for_each_entry(accel_vif_state, - &accelerator->vif_states, link) { - if (accel_vif_state->dev == dev) - accelerator_set_vif_state_hooks - (accel_vif_state); - } - - spin_unlock_irqrestore - (&accelerator->vif_states_lock, flags1); - break; - } - } - spin_unlock_irqrestore(&accelerators_lock, flags); -} -EXPORT_SYMBOL_GPL(netfront_accelerator_ready); - - -/* * Remove the hooks from a single vif state. */ static void @@ -467,16 +544,21 @@ static void accelerator_remove_hooks(str if(vif_state->hooks) { hooks = vif_state->hooks; - accelerator_remove_single_hook(accelerator, vif_state); /* Last chance to get statistics from the accelerator */ hooks->get_stats(vif_state->np->netdev, &vif_state->np->stats); - } - - spin_unlock_irqrestore(&accelerator->vif_states_lock, flags); - - accelerator->hooks->remove(vif_state->dev); + + spin_unlock_irqrestore(&accelerator->vif_states_lock, + flags); + + accelerator_remove_single_hook(accelerator, vif_state); + + accelerator->hooks->remove(vif_state->dev); + } else { + spin_unlock_irqrestore(&accelerator->vif_states_lock, + flags); + } } accelerator->hooks = NULL; @@ -522,6 +604,12 @@ static int do_remove(struct netfront_inf if (np->accel_vif_state.hooks) { hooks = np->accel_vif_state.hooks; + + /* Last chance to get statistics from the accelerator */ + hooks->get_stats(np->netdev, &np->stats); + + spin_unlock_irqrestore(&accelerator->vif_states_lock, + *lock_flags); /* * Try and do the opposite of accelerator_probe_new_vif @@ -531,14 +619,6 @@ static int do_remove(struct netfront_inf accelerator_remove_single_hook(accelerator, &np->accel_vif_state); - /* Last chance to get statistics from the accelerator */ - hooks->get_stats(np->netdev, &np->stats); - } - - if (accelerator->hooks) { - spin_unlock_irqrestore(&accelerator->vif_states_lock, - *lock_flags); - rc = accelerator->hooks->remove(dev); spin_lock_irqsave(&accelerator->vif_states_lock, *lock_flags); @@ -546,21 +626,19 @@ static int do_remove(struct netfront_inf return rc; } - - -int netfront_accelerator_call_remove(struct netfront_info *np, - struct xenbus_device *dev) + + +static int netfront_remove_accelerator(struct netfront_info *np, + struct xenbus_device *dev) { struct netfront_accelerator *accelerator; struct netfront_accel_vif_state *tmp_vif_state; unsigned long flags; int rc = 0; - mutex_lock(&accelerator_mutex); - /* Check that we've got a device that was accelerated */ if (np->accelerator == NULL) - goto out; + return rc; accelerator = np->accelerator; @@ -579,17 +657,30 @@ int netfront_accelerator_call_remove(str np->accelerator = NULL; spin_unlock_irqrestore(&accelerator->vif_states_lock, flags); - out: + + return rc; +} + + +int netfront_accelerator_call_remove(struct netfront_info *np, + struct xenbus_device *dev) +{ + int rc; + netfront_accelerator_remove_watch(np); + mutex_lock(&accelerator_mutex); + rc = netfront_remove_accelerator(np, dev); mutex_unlock(&accelerator_mutex); return rc; } - + int netfront_accelerator_suspend(struct netfront_info *np, struct xenbus_device *dev) { unsigned long flags; int rc = 0; + + netfront_accelerator_remove_watch(np); mutex_lock(&accelerator_mutex); @@ -641,6 +732,7 @@ int netfront_accelerator_suspend_cancel( out: mutex_unlock(&accelerator_mutex); + netfront_accelerator_add_watch(np); return 0; } diff -r 7db9c653b4f9 -r 41e34ec8d249 drivers/xen/netfront/netfront.c --- a/drivers/xen/netfront/netfront.c Mon Dec 17 13:41:07 2007 -0700 +++ b/drivers/xen/netfront/netfront.c Wed Dec 19 14:47:41 2007 +0000 @@ -378,6 +378,10 @@ static int talk_to_backend(struct xenbus if (err) goto out; + /* This will load an accelerator if one is configured when the + * watch fires */ + netfront_accelerator_add_watch(info); + again: err = xenbus_transaction_start(&xbt); if (err) { @@ -452,6 +456,7 @@ again: xenbus_transaction_end(xbt, 1); xenbus_dev_fatal(dev, err, "%s", message); destroy_ring: + netfront_accelerator_call_remove(info, dev); netif_disconnect_backend(info); out: return err; @@ -1746,9 +1751,7 @@ static int network_connect(struct net_de struct sk_buff *skb; grant_ref_t ref; netif_rx_request_t *req; - unsigned int feature_rx_copy, feature_rx_flip, feature_accel; - char *accel_frontend; - int accel_len; + unsigned int feature_rx_copy, feature_rx_flip; err = xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-rx-copy", "%u", &feature_rx_copy); @@ -1759,12 +1762,6 @@ static int network_connect(struct net_de if (err != 1) feature_rx_flip = 1; - feature_accel = 1; - accel_frontend = xenbus_read(XBT_NIL, np->xbdev->otherend, - "accel-frontend", &accel_len); - if (IS_ERR(accel_frontend)) - feature_accel = 0; - /* * Copy packets on receive path if: * (a) This was requested by user, and the backend supports it; or @@ -1776,11 +1773,6 @@ static int network_connect(struct net_de err = talk_to_backend(np->xbdev, np); if (err) return err; - - if (feature_accel) { - netfront_load_accelerator(np, np->xbdev, accel_frontend); - kfree(accel_frontend); - } xennet_set_features(dev); diff -r 7db9c653b4f9 -r 41e34ec8d249 drivers/xen/netfront/netfront.h --- a/drivers/xen/netfront/netfront.h Mon Dec 17 13:41:07 2007 -0700 +++ b/drivers/xen/netfront/netfront.h Wed Dec 19 14:47:41 2007 +0000 @@ -95,7 +95,7 @@ struct netfront_accel_hooks { /* Version of API/protocol for communication between netfront and acceleration plugin supported */ -#define NETFRONT_ACCEL_VERSION 0x00010002 +#define NETFRONT_ACCEL_VERSION 0x00010003 /* * Per-netfront device state for the accelerator. This is used to @@ -108,6 +108,13 @@ struct netfront_accel_vif_state { struct xenbus_device *dev; struct netfront_info *np; struct netfront_accel_hooks *hooks; + + /* Watch on the accelerator configuration value */ + struct xenbus_watch accel_watch; + /* Work item to process change in accelerator */ + struct work_struct accel_work; + /* The string from xenbus last time accel_watch fired */ + char *accel_frontend; }; /* @@ -210,18 +217,6 @@ extern int netfront_accelerator_loaded(i struct netfront_accel_hooks *hooks); /* - * Called when an accelerator plugin is ready to accelerate a device * - * that has been passed to it from netfront using the "new_device" - * hook. - * - * frontend: the string describing the accelerator. Must match the - * one passed to netfront_accelerator_loaded() - * dev: the xenbus device the plugin was asked to accelerate - */ -extern void netfront_accelerator_ready(const char *frontend, - struct xenbus_device *dev); - -/* * Called by an accelerator plugin module when it is about to unload. * * frontend: the string describing the accelerator. Must match the @@ -235,7 +230,6 @@ extern void netfront_accelerator_stop(co * wake, false if still busy */ extern int netfront_check_queue_ready(struct net_device *net_dev); - /* Internal-to-netfront Functions */ @@ -267,9 +261,7 @@ int netfront_accelerator_call_get_stats( int netfront_accelerator_call_get_stats(struct netfront_info *np, struct net_device *dev); extern -int netfront_load_accelerator(struct netfront_info *np, - struct xenbus_device *dev, - const char *frontend); +void netfront_accelerator_add_watch(struct netfront_info *np); extern void netif_init_accel(void); _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
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