From 2b1244a43be97f504494b557a7f7a65fe0d00dba Mon Sep 17 00:00:00 2001 From: Chris Leech Date: Thu, 8 Mar 2007 09:57:36 -0800 Subject: I/OAT: Only offload copies for TCP when there will be a context switch The performance wins come with having the DMA copy engine doing the copies in parallel with the context switch. If there is enough data ready on the socket at recv time just use a regular copy. Signed-off-by: Chris Leech --- net/ipv4/tcp.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'net') diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 450f44bb2c8e..0eb7cf1002c1 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1116,6 +1116,8 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, long timeo; struct task_struct *user_recv = NULL; int copied_early = 0; + int available = 0; + struct sk_buff *skb; lock_sock(sk); @@ -1142,7 +1144,11 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, #ifdef CONFIG_NET_DMA tp->ucopy.dma_chan = NULL; preempt_disable(); - if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && + skb = skb_peek_tail(&sk->sk_receive_queue); + if (skb) + available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); + if ((available < target) && + (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) { preempt_enable_no_resched(); tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len); @@ -1151,7 +1157,6 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, #endif do { - struct sk_buff *skb; u32 offset; /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */ @@ -1439,7 +1444,6 @@ skip_copy: #ifdef CONFIG_NET_DMA if (tp->ucopy.dma_chan) { - struct sk_buff *skb; dma_cookie_t done, used; dma_async_memcpy_issue_pending(tp->ucopy.dma_chan); -- cgit v1.2.3 From e00c5d8b4d800b95b72b3f072e1d55d7c7034702 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Thu, 8 Mar 2007 09:57:36 -0800 Subject: I/OAT: warning fix net/ipv4/tcp.c: In function 'tcp_recvmsg': net/ipv4/tcp.c:1111: warning: unused variable 'available' Signed-off-by: Andrew Morton Signed-off-by: Chris Leech --- net/ipv4/tcp.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) (limited to 'net') diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 0eb7cf1002c1..987b94403be5 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1116,7 +1116,6 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, long timeo; struct task_struct *user_recv = NULL; int copied_early = 0; - int available = 0; struct sk_buff *skb; lock_sock(sk); @@ -1145,15 +1144,22 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, tp->ucopy.dma_chan = NULL; preempt_disable(); skb = skb_peek_tail(&sk->sk_receive_queue); - if (skb) - available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); - if ((available < target) && - (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && - !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) { - preempt_enable_no_resched(); - tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len); - } else - preempt_enable_no_resched(); + { + int available = 0; + + if (skb) + available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); + if ((available < target) && + (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && + !sysctl_tcp_low_latency && + __get_cpu_var(softnet_data).net_dma) { + preempt_enable_no_resched(); + tp->ucopy.pinned_list = + dma_pin_iovec_pages(msg->msg_iov, len); + } else { + preempt_enable_no_resched(); + } + } #endif do { -- cgit v1.2.3 From d379b01e9087a582d58f4b678208a4f8d8376fe7 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 9 Jul 2007 11:56:42 -0700 Subject: dmaengine: make clients responsible for managing channels The current implementation assumes that a channel will only be used by one client at a time. In order to enable channel sharing the dmaengine core is changed to a model where clients subscribe to channel-available-events. Instead of tracking how many channels a client wants and how many it has received the core just broadcasts the available channels and lets the clients optionally take a reference. The core learns about the clients' needs at dma_event_callback time. In support of multiple operation types, clients can specify a capability mask to only be notified of channels that satisfy a certain set of capabilities. Changelog: * removed DMA_TX_ARRAY_INIT, no longer needed * dma_client_chan_free -> dma_chan_release: switch to global reference counting only at device unregistration time, before it was also happening at client unregistration time * clients now return dma_state_client to dmaengine (ack, dup, nak) * checkpatch.pl fixes * fixup merge with git-ioat Cc: Chris Leech Signed-off-by: Shannon Nelson Signed-off-by: Dan Williams Acked-by: David S. Miller --- drivers/dma/dmaengine.c | 217 ++++++++++++++++++++++++---------------------- drivers/dma/ioatdma.c | 1 - drivers/dma/ioatdma.h | 3 - include/linux/dmaengine.h | 58 ++++++++----- net/core/dev.c | 112 ++++++++++++++++-------- 5 files changed, 224 insertions(+), 167 deletions(-) (limited to 'net') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 404cc7b6e705..82489923af09 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -37,11 +37,11 @@ * Each device has a channels list, which runs unlocked but is never modified * once the device is registered, it's just setup by the driver. * - * Each client has a channels list, it's only modified under the client->lock - * and in an RCU callback, so it's safe to read under rcu_read_lock(). + * Each client is responsible for keeping track of the channels it uses. See + * the definition of dma_event_callback in dmaengine.h. * * Each device has a kref, which is initialized to 1 when the device is - * registered. A kref_put is done for each class_device registered. When the + * registered. A kref_get is done for each class_device registered. When the * class_device is released, the coresponding kref_put is done in the release * method. Every time one of the device's channels is allocated to a client, * a kref_get occurs. When the channel is freed, the coresponding kref_put @@ -51,10 +51,12 @@ * references to finish. * * Each channel has an open-coded implementation of Rusty Russell's "bigref," - * with a kref and a per_cpu local_t. A single reference is set when on an - * ADDED event, and removed with a REMOVE event. Net DMA client takes an - * extra reference per outstanding transaction. The relase function does a - * kref_put on the device. -ChrisL + * with a kref and a per_cpu local_t. A dma_chan_get is called when a client + * signals that it wants to use a channel, and dma_chan_put is called when + * a channel is removed or a client using it is unregesitered. A client can + * take extra references per outstanding transaction, as is the case with + * the NET DMA client. The release function does a kref_put on the device. + * -ChrisL, DanW */ #include @@ -102,8 +104,19 @@ static ssize_t show_bytes_transferred(struct class_device *cd, char *buf) static ssize_t show_in_use(struct class_device *cd, char *buf) { struct dma_chan *chan = container_of(cd, struct dma_chan, class_dev); + int in_use = 0; + + if (unlikely(chan->slow_ref) && + atomic_read(&chan->refcount.refcount) > 1) + in_use = 1; + else { + if (local_read(&(per_cpu_ptr(chan->local, + get_cpu())->refcount)) > 0) + in_use = 1; + put_cpu(); + } - return sprintf(buf, "%d\n", (chan->client ? 1 : 0)); + return sprintf(buf, "%d\n", in_use); } static struct class_device_attribute dma_class_attrs[] = { @@ -129,42 +142,53 @@ static struct class dma_devclass = { /* --- client and device registration --- */ +#define dma_chan_satisfies_mask(chan, mask) \ + __dma_chan_satisfies_mask((chan), &(mask)) +static int +__dma_chan_satisfies_mask(struct dma_chan *chan, dma_cap_mask_t *want) +{ + dma_cap_mask_t has; + + bitmap_and(has.bits, want->bits, chan->device->cap_mask.bits, + DMA_TX_TYPE_END); + return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END); +} + /** - * dma_client_chan_alloc - try to allocate a channel to a client + * dma_client_chan_alloc - try to allocate channels to a client * @client: &dma_client * * Called with dma_list_mutex held. */ -static struct dma_chan *dma_client_chan_alloc(struct dma_client *client) +static void dma_client_chan_alloc(struct dma_client *client) { struct dma_device *device; struct dma_chan *chan; - unsigned long flags; int desc; /* allocated descriptor count */ + enum dma_state_client ack; - /* Find a channel, any DMA engine will do */ - list_for_each_entry(device, &dma_device_list, global_node) { + /* Find a channel */ + list_for_each_entry(device, &dma_device_list, global_node) list_for_each_entry(chan, &device->channels, device_node) { - if (chan->client) + if (!dma_chan_satisfies_mask(chan, client->cap_mask)) continue; desc = chan->device->device_alloc_chan_resources(chan); if (desc >= 0) { - kref_get(&device->refcount); - kref_init(&chan->refcount); - chan->slow_ref = 0; - INIT_RCU_HEAD(&chan->rcu); - chan->client = client; - spin_lock_irqsave(&client->lock, flags); - list_add_tail_rcu(&chan->client_node, - &client->channels); - spin_unlock_irqrestore(&client->lock, flags); - return chan; + ack = client->event_callback(client, + chan, + DMA_RESOURCE_AVAILABLE); + + /* we are done once this client rejects + * an available resource + */ + if (ack == DMA_ACK) { + dma_chan_get(chan); + kref_get(&device->refcount); + } else if (ack == DMA_NAK) + return; } } - } - - return NULL; } enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie) @@ -193,7 +217,6 @@ void dma_chan_cleanup(struct kref *kref) { struct dma_chan *chan = container_of(kref, struct dma_chan, refcount); chan->device->device_free_chan_resources(chan); - chan->client = NULL; kref_put(&chan->device->refcount, dma_async_device_cleanup); } EXPORT_SYMBOL(dma_chan_cleanup); @@ -209,7 +232,7 @@ static void dma_chan_free_rcu(struct rcu_head *rcu) kref_put(&chan->refcount, dma_chan_cleanup); } -static void dma_client_chan_free(struct dma_chan *chan) +static void dma_chan_release(struct dma_chan *chan) { atomic_add(0x7FFFFFFF, &chan->refcount.refcount); chan->slow_ref = 1; @@ -217,70 +240,57 @@ static void dma_client_chan_free(struct dma_chan *chan) } /** - * dma_chans_rebalance - reallocate channels to clients - * - * When the number of DMA channel in the system changes, - * channels need to be rebalanced among clients. + * dma_chans_notify_available - broadcast available channels to the clients */ -static void dma_chans_rebalance(void) +static void dma_clients_notify_available(void) { struct dma_client *client; - struct dma_chan *chan; - unsigned long flags; mutex_lock(&dma_list_mutex); - list_for_each_entry(client, &dma_client_list, global_node) { - while (client->chans_desired > client->chan_count) { - chan = dma_client_chan_alloc(client); - if (!chan) - break; - client->chan_count++; - client->event_callback(client, - chan, - DMA_RESOURCE_ADDED); - } - while (client->chans_desired < client->chan_count) { - spin_lock_irqsave(&client->lock, flags); - chan = list_entry(client->channels.next, - struct dma_chan, - client_node); - list_del_rcu(&chan->client_node); - spin_unlock_irqrestore(&client->lock, flags); - client->chan_count--; - client->event_callback(client, - chan, - DMA_RESOURCE_REMOVED); - dma_client_chan_free(chan); - } - } + list_for_each_entry(client, &dma_client_list, global_node) + dma_client_chan_alloc(client); mutex_unlock(&dma_list_mutex); } /** - * dma_async_client_register - allocate and register a &dma_client - * @event_callback: callback for notification of channel addition/removal + * dma_chans_notify_available - tell the clients that a channel is going away + * @chan: channel on its way out */ -struct dma_client *dma_async_client_register(dma_event_callback event_callback) +static void dma_clients_notify_removed(struct dma_chan *chan) { struct dma_client *client; + enum dma_state_client ack; - client = kzalloc(sizeof(*client), GFP_KERNEL); - if (!client) - return NULL; + mutex_lock(&dma_list_mutex); + + list_for_each_entry(client, &dma_client_list, global_node) { + ack = client->event_callback(client, chan, + DMA_RESOURCE_REMOVED); + + /* client was holding resources for this channel so + * free it + */ + if (ack == DMA_ACK) { + dma_chan_put(chan); + kref_put(&chan->device->refcount, + dma_async_device_cleanup); + } + } - INIT_LIST_HEAD(&client->channels); - spin_lock_init(&client->lock); - client->chans_desired = 0; - client->chan_count = 0; - client->event_callback = event_callback; + mutex_unlock(&dma_list_mutex); +} +/** + * dma_async_client_register - register a &dma_client + * @client: ptr to a client structure with valid 'event_callback' and 'cap_mask' + */ +void dma_async_client_register(struct dma_client *client) +{ mutex_lock(&dma_list_mutex); list_add_tail(&client->global_node, &dma_client_list); mutex_unlock(&dma_list_mutex); - - return client; } EXPORT_SYMBOL(dma_async_client_register); @@ -292,40 +302,42 @@ EXPORT_SYMBOL(dma_async_client_register); */ void dma_async_client_unregister(struct dma_client *client) { + struct dma_device *device; struct dma_chan *chan; + enum dma_state_client ack; if (!client) return; - rcu_read_lock(); - list_for_each_entry_rcu(chan, &client->channels, client_node) - dma_client_chan_free(chan); - rcu_read_unlock(); - mutex_lock(&dma_list_mutex); + /* free all channels the client is holding */ + list_for_each_entry(device, &dma_device_list, global_node) + list_for_each_entry(chan, &device->channels, device_node) { + ack = client->event_callback(client, chan, + DMA_RESOURCE_REMOVED); + + if (ack == DMA_ACK) { + dma_chan_put(chan); + kref_put(&chan->device->refcount, + dma_async_device_cleanup); + } + } + list_del(&client->global_node); mutex_unlock(&dma_list_mutex); - - kfree(client); - dma_chans_rebalance(); } EXPORT_SYMBOL(dma_async_client_unregister); /** - * dma_async_client_chan_request - request DMA channels - * @client: &dma_client - * @number: count of DMA channels requested - * - * Clients call dma_async_client_chan_request() to specify how many - * DMA channels they need, 0 to free all currently allocated. - * The resulting allocations/frees are indicated to the client via the - * event callback. + * dma_async_client_chan_request - send all available channels to the + * client that satisfy the capability mask + * @client - requester */ -void dma_async_client_chan_request(struct dma_client *client, - unsigned int number) +void dma_async_client_chan_request(struct dma_client *client) { - client->chans_desired = number; - dma_chans_rebalance(); + mutex_lock(&dma_list_mutex); + dma_client_chan_alloc(client); + mutex_unlock(&dma_list_mutex); } EXPORT_SYMBOL(dma_async_client_chan_request); @@ -386,13 +398,16 @@ int dma_async_device_register(struct dma_device *device) } kref_get(&device->refcount); + kref_init(&chan->refcount); + chan->slow_ref = 0; + INIT_RCU_HEAD(&chan->rcu); } mutex_lock(&dma_list_mutex); list_add_tail(&device->global_node, &dma_device_list); mutex_unlock(&dma_list_mutex); - dma_chans_rebalance(); + dma_clients_notify_available(); return 0; @@ -428,26 +443,16 @@ static void dma_async_device_cleanup(struct kref *kref) void dma_async_device_unregister(struct dma_device *device) { struct dma_chan *chan; - unsigned long flags; mutex_lock(&dma_list_mutex); list_del(&device->global_node); mutex_unlock(&dma_list_mutex); list_for_each_entry(chan, &device->channels, device_node) { - if (chan->client) { - spin_lock_irqsave(&chan->client->lock, flags); - list_del(&chan->client_node); - chan->client->chan_count--; - spin_unlock_irqrestore(&chan->client->lock, flags); - chan->client->event_callback(chan->client, - chan, - DMA_RESOURCE_REMOVED); - dma_client_chan_free(chan); - } + dma_clients_notify_removed(chan); class_device_unregister(&chan->class_dev); + dma_chan_release(chan); } - dma_chans_rebalance(); kref_put(&device->refcount, dma_async_device_cleanup); wait_for_completion(&device->done); diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c index 171044930282..81810b3042f1 100644 --- a/drivers/dma/ioatdma.c +++ b/drivers/dma/ioatdma.c @@ -72,7 +72,6 @@ static int enumerate_dma_channels(struct ioat_device *device) INIT_LIST_HEAD(&ioat_chan->used_desc); /* This should be made common somewhere in dmaengine.c */ ioat_chan->common.device = &device->common; - ioat_chan->common.client = NULL; list_add_tail(&ioat_chan->common.device_node, &device->common.channels); } diff --git a/drivers/dma/ioatdma.h b/drivers/dma/ioatdma.h index d3f69bb15fa0..d3726478031a 100644 --- a/drivers/dma/ioatdma.h +++ b/drivers/dma/ioatdma.h @@ -30,9 +30,6 @@ #define IOAT_LOW_COMPLETION_MASK 0xffffffc0 -extern struct list_head dma_device_list; -extern struct list_head dma_client_list; - /** * struct ioat_device - internal representation of a IOAT device * @pdev: PCI-Express device diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 3de1cf71031a..a3b6035b6c86 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -29,19 +29,31 @@ #include /** - * enum dma_event - resource PNP/power managment events + * enum dma_state - resource PNP/power managment state * @DMA_RESOURCE_SUSPEND: DMA device going into low power state * @DMA_RESOURCE_RESUME: DMA device returning to full power - * @DMA_RESOURCE_ADDED: DMA device added to the system + * @DMA_RESOURCE_AVAILABLE: DMA device available to the system * @DMA_RESOURCE_REMOVED: DMA device removed from the system */ -enum dma_event { +enum dma_state { DMA_RESOURCE_SUSPEND, DMA_RESOURCE_RESUME, - DMA_RESOURCE_ADDED, + DMA_RESOURCE_AVAILABLE, DMA_RESOURCE_REMOVED, }; +/** + * enum dma_state_client - state of the channel in the client + * @DMA_ACK: client would like to use, or was using this channel + * @DMA_DUP: client has already seen this channel, or is not using this channel + * @DMA_NAK: client does not want to see any more channels + */ +enum dma_state_client { + DMA_ACK, + DMA_DUP, + DMA_NAK, +}; + /** * typedef dma_cookie_t - an opaque DMA cookie * @@ -104,7 +116,6 @@ struct dma_chan_percpu { /** * struct dma_chan - devices supply DMA channels, clients use them - * @client: ptr to the client user of this chan, will be %NULL when unused * @device: ptr to the dma device who supplies this channel, always !%NULL * @cookie: last cookie value returned to client * @chan_id: channel ID for sysfs @@ -112,12 +123,10 @@ struct dma_chan_percpu { * @refcount: kref, used in "bigref" slow-mode * @slow_ref: indicates that the DMA channel is free * @rcu: the DMA channel's RCU head - * @client_node: used to add this to the client chan list * @device_node: used to add this to the device chan list * @local: per-cpu pointer to a struct dma_chan_percpu */ struct dma_chan { - struct dma_client *client; struct dma_device *device; dma_cookie_t cookie; @@ -129,11 +138,11 @@ struct dma_chan { int slow_ref; struct rcu_head rcu; - struct list_head client_node; struct list_head device_node; struct dma_chan_percpu *local; }; + void dma_chan_cleanup(struct kref *kref); static inline void dma_chan_get(struct dma_chan *chan) @@ -158,26 +167,31 @@ static inline void dma_chan_put(struct dma_chan *chan) /* * typedef dma_event_callback - function pointer to a DMA event callback + * For each channel added to the system this routine is called for each client. + * If the client would like to use the channel it returns '1' to signal (ack) + * the dmaengine core to take out a reference on the channel and its + * corresponding device. A client must not 'ack' an available channel more + * than once. When a channel is removed all clients are notified. If a client + * is using the channel it must 'ack' the removal. A client must not 'ack' a + * removed channel more than once. + * @client - 'this' pointer for the client context + * @chan - channel to be acted upon + * @state - available or removed */ -typedef void (*dma_event_callback) (struct dma_client *client, - struct dma_chan *chan, enum dma_event event); +struct dma_client; +typedef enum dma_state_client (*dma_event_callback) (struct dma_client *client, + struct dma_chan *chan, enum dma_state state); /** * struct dma_client - info on the entity making use of DMA services * @event_callback: func ptr to call when something happens - * @chan_count: number of chans allocated - * @chans_desired: number of chans requested. Can be +/- chan_count - * @lock: protects access to the channels list - * @channels: the list of DMA channels allocated + * @cap_mask: only return channels that satisfy the requested capabilities + * a value of zero corresponds to any capability * @global_node: list_head for global dma_client_list */ struct dma_client { dma_event_callback event_callback; - unsigned int chan_count; - unsigned int chans_desired; - - spinlock_t lock; - struct list_head channels; + dma_cap_mask_t cap_mask; struct list_head global_node; }; @@ -285,10 +299,9 @@ struct dma_device { /* --- public DMA engine API --- */ -struct dma_client *dma_async_client_register(dma_event_callback event_callback); +void dma_async_client_register(struct dma_client *client); void dma_async_client_unregister(struct dma_client *client); -void dma_async_client_chan_request(struct dma_client *client, - unsigned int number); +void dma_async_client_chan_request(struct dma_client *client); dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest, void *src, size_t len); dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan, @@ -299,7 +312,6 @@ dma_cookie_t dma_async_memcpy_pg_to_pg(struct dma_chan *chan, void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx, struct dma_chan *chan); - static inline void async_tx_ack(struct dma_async_tx_descriptor *tx) { diff --git a/net/core/dev.c b/net/core/dev.c index ee051bb398a0..835202fb34c4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -151,9 +151,22 @@ static struct list_head ptype_base[16] __read_mostly; /* 16 way hashed list */ static struct list_head ptype_all __read_mostly; /* Taps */ #ifdef CONFIG_NET_DMA -static struct dma_client *net_dma_client; -static unsigned int net_dma_count; -static spinlock_t net_dma_event_lock; +struct net_dma { + struct dma_client client; + spinlock_t lock; + cpumask_t channel_mask; + struct dma_chan *channels[NR_CPUS]; +}; + +static enum dma_state_client +netdev_dma_event(struct dma_client *client, struct dma_chan *chan, + enum dma_state state); + +static struct net_dma net_dma = { + .client = { + .event_callback = netdev_dma_event, + }, +}; #endif /* @@ -2015,12 +2028,13 @@ out: * There may not be any more sk_buffs coming right now, so push * any pending DMA copies to hardware */ - if (net_dma_client) { - struct dma_chan *chan; - rcu_read_lock(); - list_for_each_entry_rcu(chan, &net_dma_client->channels, client_node) - dma_async_memcpy_issue_pending(chan); - rcu_read_unlock(); + if (!cpus_empty(net_dma.channel_mask)) { + int chan_idx; + for_each_cpu_mask(chan_idx, net_dma.channel_mask) { + struct dma_chan *chan = net_dma.channels[chan_idx]; + if (chan) + dma_async_memcpy_issue_pending(chan); + } } #endif return; @@ -3563,12 +3577,13 @@ static int dev_cpu_callback(struct notifier_block *nfb, * This is called when the number of channels allocated to the net_dma_client * changes. The net_dma_client tries to have one DMA channel per CPU. */ -static void net_dma_rebalance(void) + +static void net_dma_rebalance(struct net_dma *net_dma) { - unsigned int cpu, i, n; + unsigned int cpu, i, n, chan_idx; struct dma_chan *chan; - if (net_dma_count == 0) { + if (cpus_empty(net_dma->channel_mask)) { for_each_online_cpu(cpu) rcu_assign_pointer(per_cpu(softnet_data, cpu).net_dma, NULL); return; @@ -3577,10 +3592,12 @@ static void net_dma_rebalance(void) i = 0; cpu = first_cpu(cpu_online_map); - rcu_read_lock(); - list_for_each_entry(chan, &net_dma_client->channels, client_node) { - n = ((num_online_cpus() / net_dma_count) - + (i < (num_online_cpus() % net_dma_count) ? 1 : 0)); + for_each_cpu_mask(chan_idx, net_dma->channel_mask) { + chan = net_dma->channels[chan_idx]; + + n = ((num_online_cpus() / cpus_weight(net_dma->channel_mask)) + + (i < (num_online_cpus() % + cpus_weight(net_dma->channel_mask)) ? 1 : 0)); while(n) { per_cpu(softnet_data, cpu).net_dma = chan; @@ -3589,7 +3606,6 @@ static void net_dma_rebalance(void) } i++; } - rcu_read_unlock(); } /** @@ -3598,23 +3614,53 @@ static void net_dma_rebalance(void) * @chan: DMA channel for the event * @event: event type */ -static void netdev_dma_event(struct dma_client *client, struct dma_chan *chan, - enum dma_event event) -{ - spin_lock(&net_dma_event_lock); - switch (event) { - case DMA_RESOURCE_ADDED: - net_dma_count++; - net_dma_rebalance(); +static enum dma_state_client +netdev_dma_event(struct dma_client *client, struct dma_chan *chan, + enum dma_state state) +{ + int i, found = 0, pos = -1; + struct net_dma *net_dma = + container_of(client, struct net_dma, client); + enum dma_state_client ack = DMA_DUP; /* default: take no action */ + + spin_lock(&net_dma->lock); + switch (state) { + case DMA_RESOURCE_AVAILABLE: + for (i = 0; i < NR_CPUS; i++) + if (net_dma->channels[i] == chan) { + found = 1; + break; + } else if (net_dma->channels[i] == NULL && pos < 0) + pos = i; + + if (!found && pos >= 0) { + ack = DMA_ACK; + net_dma->channels[pos] = chan; + cpu_set(pos, net_dma->channel_mask); + net_dma_rebalance(net_dma); + } break; case DMA_RESOURCE_REMOVED: - net_dma_count--; - net_dma_rebalance(); + for (i = 0; i < NR_CPUS; i++) + if (net_dma->channels[i] == chan) { + found = 1; + pos = i; + break; + } + + if (found) { + ack = DMA_ACK; + cpu_clear(pos, net_dma->channel_mask); + net_dma->channels[i] = NULL; + net_dma_rebalance(net_dma); + } break; default: break; } - spin_unlock(&net_dma_event_lock); + spin_unlock(&net_dma->lock); + + return ack; } /** @@ -3622,12 +3668,10 @@ static void netdev_dma_event(struct dma_client *client, struct dma_chan *chan, */ static int __init netdev_dma_register(void) { - spin_lock_init(&net_dma_event_lock); - net_dma_client = dma_async_client_register(netdev_dma_event); - if (net_dma_client == NULL) - return -ENOMEM; - - dma_async_client_chan_request(net_dma_client, num_online_cpus()); + spin_lock_init(&net_dma.lock); + dma_cap_set(DMA_MEMCPY, net_dma.client.cap_mask); + dma_async_client_register(&net_dma.client); + dma_async_client_chan_request(&net_dma.client); return 0; } -- cgit v1.2.3