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 <christopher.leech@intel.com> Signed-off-by: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
7405f74bad
commit
d379b01e90
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@ -37,11 +37,11 @@
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* Each device has a channels list, which runs unlocked but is never modified
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* Each device has a channels list, which runs unlocked but is never modified
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* once the device is registered, it's just setup by the driver.
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* once the device is registered, it's just setup by the driver.
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*
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*
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* Each client has a channels list, it's only modified under the client->lock
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* Each client is responsible for keeping track of the channels it uses. See
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* and in an RCU callback, so it's safe to read under rcu_read_lock().
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* the definition of dma_event_callback in dmaengine.h.
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*
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*
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* Each device has a kref, which is initialized to 1 when the device is
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* Each device has a kref, which is initialized to 1 when the device is
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* registered. A kref_put is done for each class_device registered. When the
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* registered. A kref_get is done for each class_device registered. When the
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* class_device is released, the coresponding kref_put is done in the release
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* class_device is released, the coresponding kref_put is done in the release
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* method. Every time one of the device's channels is allocated to a client,
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* method. Every time one of the device's channels is allocated to a client,
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* a kref_get occurs. When the channel is freed, the coresponding kref_put
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* a kref_get occurs. When the channel is freed, the coresponding kref_put
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@ -51,10 +51,12 @@
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* references to finish.
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* references to finish.
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*
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*
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* Each channel has an open-coded implementation of Rusty Russell's "bigref,"
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* Each channel has an open-coded implementation of Rusty Russell's "bigref,"
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* with a kref and a per_cpu local_t. A single reference is set when on an
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* with a kref and a per_cpu local_t. A dma_chan_get is called when a client
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* ADDED event, and removed with a REMOVE event. Net DMA client takes an
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* signals that it wants to use a channel, and dma_chan_put is called when
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* extra reference per outstanding transaction. The relase function does a
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* a channel is removed or a client using it is unregesitered. A client can
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* kref_put on the device. -ChrisL
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* take extra references per outstanding transaction, as is the case with
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* the NET DMA client. The release function does a kref_put on the device.
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* -ChrisL, DanW
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*/
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*/
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#include <linux/init.h>
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#include <linux/init.h>
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@ -102,8 +104,19 @@ static ssize_t show_bytes_transferred(struct class_device *cd, char *buf)
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static ssize_t show_in_use(struct class_device *cd, char *buf)
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static ssize_t show_in_use(struct class_device *cd, char *buf)
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{
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{
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struct dma_chan *chan = container_of(cd, struct dma_chan, class_dev);
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struct dma_chan *chan = container_of(cd, struct dma_chan, class_dev);
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int in_use = 0;
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return sprintf(buf, "%d\n", (chan->client ? 1 : 0));
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if (unlikely(chan->slow_ref) &&
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atomic_read(&chan->refcount.refcount) > 1)
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in_use = 1;
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else {
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if (local_read(&(per_cpu_ptr(chan->local,
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get_cpu())->refcount)) > 0)
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in_use = 1;
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put_cpu();
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}
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return sprintf(buf, "%d\n", in_use);
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}
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}
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static struct class_device_attribute dma_class_attrs[] = {
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static struct class_device_attribute dma_class_attrs[] = {
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@ -129,42 +142,53 @@ static struct class dma_devclass = {
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/* --- client and device registration --- */
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/* --- client and device registration --- */
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#define dma_chan_satisfies_mask(chan, mask) \
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__dma_chan_satisfies_mask((chan), &(mask))
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static int
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__dma_chan_satisfies_mask(struct dma_chan *chan, dma_cap_mask_t *want)
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{
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dma_cap_mask_t has;
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bitmap_and(has.bits, want->bits, chan->device->cap_mask.bits,
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DMA_TX_TYPE_END);
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return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
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}
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/**
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/**
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* dma_client_chan_alloc - try to allocate a channel to a client
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* dma_client_chan_alloc - try to allocate channels to a client
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* @client: &dma_client
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* @client: &dma_client
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*
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*
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* Called with dma_list_mutex held.
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* Called with dma_list_mutex held.
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*/
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*/
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static struct dma_chan *dma_client_chan_alloc(struct dma_client *client)
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static void dma_client_chan_alloc(struct dma_client *client)
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{
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{
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struct dma_device *device;
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struct dma_device *device;
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struct dma_chan *chan;
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struct dma_chan *chan;
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unsigned long flags;
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int desc; /* allocated descriptor count */
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int desc; /* allocated descriptor count */
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enum dma_state_client ack;
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/* Find a channel, any DMA engine will do */
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/* Find a channel */
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list_for_each_entry(device, &dma_device_list, global_node) {
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list_for_each_entry(device, &dma_device_list, global_node)
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list_for_each_entry(chan, &device->channels, device_node) {
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list_for_each_entry(chan, &device->channels, device_node) {
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if (chan->client)
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if (!dma_chan_satisfies_mask(chan, client->cap_mask))
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continue;
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continue;
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desc = chan->device->device_alloc_chan_resources(chan);
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desc = chan->device->device_alloc_chan_resources(chan);
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if (desc >= 0) {
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if (desc >= 0) {
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kref_get(&device->refcount);
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ack = client->event_callback(client,
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kref_init(&chan->refcount);
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chan,
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chan->slow_ref = 0;
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DMA_RESOURCE_AVAILABLE);
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INIT_RCU_HEAD(&chan->rcu);
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chan->client = client;
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/* we are done once this client rejects
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spin_lock_irqsave(&client->lock, flags);
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* an available resource
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list_add_tail_rcu(&chan->client_node,
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*/
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&client->channels);
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if (ack == DMA_ACK) {
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spin_unlock_irqrestore(&client->lock, flags);
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dma_chan_get(chan);
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return chan;
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kref_get(&device->refcount);
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} else if (ack == DMA_NAK)
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return;
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}
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}
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}
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}
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}
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return NULL;
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}
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}
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enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
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enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
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@ -193,7 +217,6 @@ void dma_chan_cleanup(struct kref *kref)
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{
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{
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struct dma_chan *chan = container_of(kref, struct dma_chan, refcount);
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struct dma_chan *chan = container_of(kref, struct dma_chan, refcount);
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chan->device->device_free_chan_resources(chan);
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chan->device->device_free_chan_resources(chan);
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chan->client = NULL;
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kref_put(&chan->device->refcount, dma_async_device_cleanup);
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kref_put(&chan->device->refcount, dma_async_device_cleanup);
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}
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}
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EXPORT_SYMBOL(dma_chan_cleanup);
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EXPORT_SYMBOL(dma_chan_cleanup);
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@ -209,7 +232,7 @@ static void dma_chan_free_rcu(struct rcu_head *rcu)
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kref_put(&chan->refcount, dma_chan_cleanup);
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kref_put(&chan->refcount, dma_chan_cleanup);
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}
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}
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static void dma_client_chan_free(struct dma_chan *chan)
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static void dma_chan_release(struct dma_chan *chan)
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{
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{
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atomic_add(0x7FFFFFFF, &chan->refcount.refcount);
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atomic_add(0x7FFFFFFF, &chan->refcount.refcount);
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chan->slow_ref = 1;
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chan->slow_ref = 1;
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@ -217,41 +240,42 @@ static void dma_client_chan_free(struct dma_chan *chan)
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}
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}
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/**
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/**
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* dma_chans_rebalance - reallocate channels to clients
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* dma_chans_notify_available - broadcast available channels to the clients
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*
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* When the number of DMA channel in the system changes,
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* channels need to be rebalanced among clients.
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*/
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*/
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static void dma_chans_rebalance(void)
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static void dma_clients_notify_available(void)
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{
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{
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struct dma_client *client;
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struct dma_client *client;
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struct dma_chan *chan;
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unsigned long flags;
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mutex_lock(&dma_list_mutex);
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list_for_each_entry(client, &dma_client_list, global_node)
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dma_client_chan_alloc(client);
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mutex_unlock(&dma_list_mutex);
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}
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/**
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* dma_chans_notify_available - tell the clients that a channel is going away
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* @chan: channel on its way out
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*/
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static void dma_clients_notify_removed(struct dma_chan *chan)
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{
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struct dma_client *client;
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enum dma_state_client ack;
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mutex_lock(&dma_list_mutex);
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mutex_lock(&dma_list_mutex);
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list_for_each_entry(client, &dma_client_list, global_node) {
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list_for_each_entry(client, &dma_client_list, global_node) {
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while (client->chans_desired > client->chan_count) {
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ack = client->event_callback(client, chan,
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chan = dma_client_chan_alloc(client);
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DMA_RESOURCE_REMOVED);
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if (!chan)
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break;
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/* client was holding resources for this channel so
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client->chan_count++;
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* free it
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client->event_callback(client,
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*/
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chan,
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if (ack == DMA_ACK) {
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DMA_RESOURCE_ADDED);
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dma_chan_put(chan);
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}
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kref_put(&chan->device->refcount,
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while (client->chans_desired < client->chan_count) {
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dma_async_device_cleanup);
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spin_lock_irqsave(&client->lock, flags);
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chan = list_entry(client->channels.next,
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struct dma_chan,
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client_node);
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list_del_rcu(&chan->client_node);
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spin_unlock_irqrestore(&client->lock, flags);
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client->chan_count--;
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client->event_callback(client,
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chan,
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DMA_RESOURCE_REMOVED);
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dma_client_chan_free(chan);
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}
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}
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}
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}
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@ -259,28 +283,14 @@ static void dma_chans_rebalance(void)
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}
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}
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/**
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/**
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* dma_async_client_register - allocate and register a &dma_client
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* dma_async_client_register - register a &dma_client
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* @event_callback: callback for notification of channel addition/removal
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* @client: ptr to a client structure with valid 'event_callback' and 'cap_mask'
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*/
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*/
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struct dma_client *dma_async_client_register(dma_event_callback event_callback)
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void dma_async_client_register(struct dma_client *client)
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{
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{
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struct dma_client *client;
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client = kzalloc(sizeof(*client), GFP_KERNEL);
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if (!client)
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return NULL;
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INIT_LIST_HEAD(&client->channels);
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spin_lock_init(&client->lock);
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client->chans_desired = 0;
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client->chan_count = 0;
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client->event_callback = event_callback;
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mutex_lock(&dma_list_mutex);
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mutex_lock(&dma_list_mutex);
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list_add_tail(&client->global_node, &dma_client_list);
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list_add_tail(&client->global_node, &dma_client_list);
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mutex_unlock(&dma_list_mutex);
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mutex_unlock(&dma_list_mutex);
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return client;
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}
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}
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EXPORT_SYMBOL(dma_async_client_register);
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EXPORT_SYMBOL(dma_async_client_register);
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@ -292,40 +302,42 @@ EXPORT_SYMBOL(dma_async_client_register);
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*/
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*/
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void dma_async_client_unregister(struct dma_client *client)
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void dma_async_client_unregister(struct dma_client *client)
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{
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{
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struct dma_device *device;
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struct dma_chan *chan;
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struct dma_chan *chan;
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enum dma_state_client ack;
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if (!client)
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if (!client)
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return;
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return;
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rcu_read_lock();
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list_for_each_entry_rcu(chan, &client->channels, client_node)
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dma_client_chan_free(chan);
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rcu_read_unlock();
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mutex_lock(&dma_list_mutex);
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mutex_lock(&dma_list_mutex);
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/* free all channels the client is holding */
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list_for_each_entry(device, &dma_device_list, global_node)
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list_for_each_entry(chan, &device->channels, device_node) {
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ack = client->event_callback(client, chan,
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DMA_RESOURCE_REMOVED);
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if (ack == DMA_ACK) {
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dma_chan_put(chan);
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kref_put(&chan->device->refcount,
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dma_async_device_cleanup);
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}
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}
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list_del(&client->global_node);
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list_del(&client->global_node);
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mutex_unlock(&dma_list_mutex);
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mutex_unlock(&dma_list_mutex);
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kfree(client);
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dma_chans_rebalance();
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}
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}
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EXPORT_SYMBOL(dma_async_client_unregister);
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EXPORT_SYMBOL(dma_async_client_unregister);
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/**
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/**
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* dma_async_client_chan_request - request DMA channels
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* dma_async_client_chan_request - send all available channels to the
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* @client: &dma_client
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* client that satisfy the capability mask
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* @number: count of DMA channels requested
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* @client - requester
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*
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* Clients call dma_async_client_chan_request() to specify how many
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* DMA channels they need, 0 to free all currently allocated.
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* The resulting allocations/frees are indicated to the client via the
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* event callback.
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*/
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*/
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void dma_async_client_chan_request(struct dma_client *client,
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void dma_async_client_chan_request(struct dma_client *client)
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unsigned int number)
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{
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{
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client->chans_desired = number;
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mutex_lock(&dma_list_mutex);
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dma_chans_rebalance();
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dma_client_chan_alloc(client);
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mutex_unlock(&dma_list_mutex);
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}
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}
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EXPORT_SYMBOL(dma_async_client_chan_request);
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EXPORT_SYMBOL(dma_async_client_chan_request);
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@ -386,13 +398,16 @@ int dma_async_device_register(struct dma_device *device)
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}
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}
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kref_get(&device->refcount);
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kref_get(&device->refcount);
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kref_init(&chan->refcount);
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chan->slow_ref = 0;
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INIT_RCU_HEAD(&chan->rcu);
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}
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}
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mutex_lock(&dma_list_mutex);
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mutex_lock(&dma_list_mutex);
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list_add_tail(&device->global_node, &dma_device_list);
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list_add_tail(&device->global_node, &dma_device_list);
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mutex_unlock(&dma_list_mutex);
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mutex_unlock(&dma_list_mutex);
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|
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dma_chans_rebalance();
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dma_clients_notify_available();
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return 0;
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return 0;
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|
@ -428,26 +443,16 @@ static void dma_async_device_cleanup(struct kref *kref)
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void dma_async_device_unregister(struct dma_device *device)
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void dma_async_device_unregister(struct dma_device *device)
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{
|
{
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struct dma_chan *chan;
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struct dma_chan *chan;
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unsigned long flags;
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|
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|
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mutex_lock(&dma_list_mutex);
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mutex_lock(&dma_list_mutex);
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list_del(&device->global_node);
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list_del(&device->global_node);
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mutex_unlock(&dma_list_mutex);
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mutex_unlock(&dma_list_mutex);
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|
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list_for_each_entry(chan, &device->channels, device_node) {
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list_for_each_entry(chan, &device->channels, device_node) {
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if (chan->client) {
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dma_clients_notify_removed(chan);
|
||||||
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);
|
|
||||||
}
|
|
||||||
class_device_unregister(&chan->class_dev);
|
class_device_unregister(&chan->class_dev);
|
||||||
|
dma_chan_release(chan);
|
||||||
}
|
}
|
||||||
dma_chans_rebalance();
|
|
||||||
|
|
||||||
kref_put(&device->refcount, dma_async_device_cleanup);
|
kref_put(&device->refcount, dma_async_device_cleanup);
|
||||||
wait_for_completion(&device->done);
|
wait_for_completion(&device->done);
|
||||||
|
|
|
@ -72,7 +72,6 @@ static int enumerate_dma_channels(struct ioat_device *device)
|
||||||
INIT_LIST_HEAD(&ioat_chan->used_desc);
|
INIT_LIST_HEAD(&ioat_chan->used_desc);
|
||||||
/* This should be made common somewhere in dmaengine.c */
|
/* This should be made common somewhere in dmaengine.c */
|
||||||
ioat_chan->common.device = &device->common;
|
ioat_chan->common.device = &device->common;
|
||||||
ioat_chan->common.client = NULL;
|
|
||||||
list_add_tail(&ioat_chan->common.device_node,
|
list_add_tail(&ioat_chan->common.device_node,
|
||||||
&device->common.channels);
|
&device->common.channels);
|
||||||
}
|
}
|
||||||
|
|
|
@ -30,9 +30,6 @@
|
||||||
|
|
||||||
#define IOAT_LOW_COMPLETION_MASK 0xffffffc0
|
#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
|
* struct ioat_device - internal representation of a IOAT device
|
||||||
* @pdev: PCI-Express device
|
* @pdev: PCI-Express device
|
||||||
|
|
|
@ -29,19 +29,31 @@
|
||||||
#include <linux/dma-mapping.h>
|
#include <linux/dma-mapping.h>
|
||||||
|
|
||||||
/**
|
/**
|
||||||
* 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_SUSPEND: DMA device going into low power state
|
||||||
* @DMA_RESOURCE_RESUME: DMA device returning to full power
|
* @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
|
* @DMA_RESOURCE_REMOVED: DMA device removed from the system
|
||||||
*/
|
*/
|
||||||
enum dma_event {
|
enum dma_state {
|
||||||
DMA_RESOURCE_SUSPEND,
|
DMA_RESOURCE_SUSPEND,
|
||||||
DMA_RESOURCE_RESUME,
|
DMA_RESOURCE_RESUME,
|
||||||
DMA_RESOURCE_ADDED,
|
DMA_RESOURCE_AVAILABLE,
|
||||||
DMA_RESOURCE_REMOVED,
|
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
|
* 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
|
* 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
|
* @device: ptr to the dma device who supplies this channel, always !%NULL
|
||||||
* @cookie: last cookie value returned to client
|
* @cookie: last cookie value returned to client
|
||||||
* @chan_id: channel ID for sysfs
|
* @chan_id: channel ID for sysfs
|
||||||
|
@ -112,12 +123,10 @@ struct dma_chan_percpu {
|
||||||
* @refcount: kref, used in "bigref" slow-mode
|
* @refcount: kref, used in "bigref" slow-mode
|
||||||
* @slow_ref: indicates that the DMA channel is free
|
* @slow_ref: indicates that the DMA channel is free
|
||||||
* @rcu: the DMA channel's RCU head
|
* @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
|
* @device_node: used to add this to the device chan list
|
||||||
* @local: per-cpu pointer to a struct dma_chan_percpu
|
* @local: per-cpu pointer to a struct dma_chan_percpu
|
||||||
*/
|
*/
|
||||||
struct dma_chan {
|
struct dma_chan {
|
||||||
struct dma_client *client;
|
|
||||||
struct dma_device *device;
|
struct dma_device *device;
|
||||||
dma_cookie_t cookie;
|
dma_cookie_t cookie;
|
||||||
|
|
||||||
|
@ -129,11 +138,11 @@ struct dma_chan {
|
||||||
int slow_ref;
|
int slow_ref;
|
||||||
struct rcu_head rcu;
|
struct rcu_head rcu;
|
||||||
|
|
||||||
struct list_head client_node;
|
|
||||||
struct list_head device_node;
|
struct list_head device_node;
|
||||||
struct dma_chan_percpu *local;
|
struct dma_chan_percpu *local;
|
||||||
};
|
};
|
||||||
|
|
||||||
|
|
||||||
void dma_chan_cleanup(struct kref *kref);
|
void dma_chan_cleanup(struct kref *kref);
|
||||||
|
|
||||||
static inline void dma_chan_get(struct dma_chan *chan)
|
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
|
* 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_client;
|
||||||
struct dma_chan *chan, enum dma_event event);
|
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
|
* struct dma_client - info on the entity making use of DMA services
|
||||||
* @event_callback: func ptr to call when something happens
|
* @event_callback: func ptr to call when something happens
|
||||||
* @chan_count: number of chans allocated
|
* @cap_mask: only return channels that satisfy the requested capabilities
|
||||||
* @chans_desired: number of chans requested. Can be +/- chan_count
|
* a value of zero corresponds to any capability
|
||||||
* @lock: protects access to the channels list
|
|
||||||
* @channels: the list of DMA channels allocated
|
|
||||||
* @global_node: list_head for global dma_client_list
|
* @global_node: list_head for global dma_client_list
|
||||||
*/
|
*/
|
||||||
struct dma_client {
|
struct dma_client {
|
||||||
dma_event_callback event_callback;
|
dma_event_callback event_callback;
|
||||||
unsigned int chan_count;
|
dma_cap_mask_t cap_mask;
|
||||||
unsigned int chans_desired;
|
|
||||||
|
|
||||||
spinlock_t lock;
|
|
||||||
struct list_head channels;
|
|
||||||
struct list_head global_node;
|
struct list_head global_node;
|
||||||
};
|
};
|
||||||
|
|
||||||
|
@ -285,10 +299,9 @@ struct dma_device {
|
||||||
|
|
||||||
/* --- public DMA engine API --- */
|
/* --- 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_unregister(struct dma_client *client);
|
||||||
void dma_async_client_chan_request(struct dma_client *client,
|
void dma_async_client_chan_request(struct dma_client *client);
|
||||||
unsigned int number);
|
|
||||||
dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
|
dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
|
||||||
void *dest, void *src, size_t len);
|
void *dest, void *src, size_t len);
|
||||||
dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,
|
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,
|
void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
|
||||||
struct dma_chan *chan);
|
struct dma_chan *chan);
|
||||||
|
|
||||||
|
|
||||||
static inline void
|
static inline void
|
||||||
async_tx_ack(struct dma_async_tx_descriptor *tx)
|
async_tx_ack(struct dma_async_tx_descriptor *tx)
|
||||||
{
|
{
|
||||||
|
|
110
net/core/dev.c
110
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 */
|
static struct list_head ptype_all __read_mostly; /* Taps */
|
||||||
|
|
||||||
#ifdef CONFIG_NET_DMA
|
#ifdef CONFIG_NET_DMA
|
||||||
static struct dma_client *net_dma_client;
|
struct net_dma {
|
||||||
static unsigned int net_dma_count;
|
struct dma_client client;
|
||||||
static spinlock_t net_dma_event_lock;
|
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
|
#endif
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
@ -2015,12 +2028,13 @@ out:
|
||||||
* There may not be any more sk_buffs coming right now, so push
|
* There may not be any more sk_buffs coming right now, so push
|
||||||
* any pending DMA copies to hardware
|
* any pending DMA copies to hardware
|
||||||
*/
|
*/
|
||||||
if (net_dma_client) {
|
if (!cpus_empty(net_dma.channel_mask)) {
|
||||||
struct dma_chan *chan;
|
int chan_idx;
|
||||||
rcu_read_lock();
|
for_each_cpu_mask(chan_idx, net_dma.channel_mask) {
|
||||||
list_for_each_entry_rcu(chan, &net_dma_client->channels, client_node)
|
struct dma_chan *chan = net_dma.channels[chan_idx];
|
||||||
dma_async_memcpy_issue_pending(chan);
|
if (chan)
|
||||||
rcu_read_unlock();
|
dma_async_memcpy_issue_pending(chan);
|
||||||
|
}
|
||||||
}
|
}
|
||||||
#endif
|
#endif
|
||||||
return;
|
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
|
* 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.
|
* 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;
|
struct dma_chan *chan;
|
||||||
|
|
||||||
if (net_dma_count == 0) {
|
if (cpus_empty(net_dma->channel_mask)) {
|
||||||
for_each_online_cpu(cpu)
|
for_each_online_cpu(cpu)
|
||||||
rcu_assign_pointer(per_cpu(softnet_data, cpu).net_dma, NULL);
|
rcu_assign_pointer(per_cpu(softnet_data, cpu).net_dma, NULL);
|
||||||
return;
|
return;
|
||||||
|
@ -3577,10 +3592,12 @@ static void net_dma_rebalance(void)
|
||||||
i = 0;
|
i = 0;
|
||||||
cpu = first_cpu(cpu_online_map);
|
cpu = first_cpu(cpu_online_map);
|
||||||
|
|
||||||
rcu_read_lock();
|
for_each_cpu_mask(chan_idx, net_dma->channel_mask) {
|
||||||
list_for_each_entry(chan, &net_dma_client->channels, client_node) {
|
chan = net_dma->channels[chan_idx];
|
||||||
n = ((num_online_cpus() / net_dma_count)
|
|
||||||
+ (i < (num_online_cpus() % net_dma_count) ? 1 : 0));
|
n = ((num_online_cpus() / cpus_weight(net_dma->channel_mask))
|
||||||
|
+ (i < (num_online_cpus() %
|
||||||
|
cpus_weight(net_dma->channel_mask)) ? 1 : 0));
|
||||||
|
|
||||||
while(n) {
|
while(n) {
|
||||||
per_cpu(softnet_data, cpu).net_dma = chan;
|
per_cpu(softnet_data, cpu).net_dma = chan;
|
||||||
|
@ -3589,7 +3606,6 @@ static void net_dma_rebalance(void)
|
||||||
}
|
}
|
||||||
i++;
|
i++;
|
||||||
}
|
}
|
||||||
rcu_read_unlock();
|
|
||||||
}
|
}
|
||||||
|
|
||||||
/**
|
/**
|
||||||
|
@ -3598,23 +3614,53 @@ static void net_dma_rebalance(void)
|
||||||
* @chan: DMA channel for the event
|
* @chan: DMA channel for the event
|
||||||
* @event: event type
|
* @event: event type
|
||||||
*/
|
*/
|
||||||
static void netdev_dma_event(struct dma_client *client, struct dma_chan *chan,
|
static enum dma_state_client
|
||||||
enum dma_event event)
|
netdev_dma_event(struct dma_client *client, struct dma_chan *chan,
|
||||||
|
enum dma_state state)
|
||||||
{
|
{
|
||||||
spin_lock(&net_dma_event_lock);
|
int i, found = 0, pos = -1;
|
||||||
switch (event) {
|
struct net_dma *net_dma =
|
||||||
case DMA_RESOURCE_ADDED:
|
container_of(client, struct net_dma, client);
|
||||||
net_dma_count++;
|
enum dma_state_client ack = DMA_DUP; /* default: take no action */
|
||||||
net_dma_rebalance();
|
|
||||||
|
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;
|
break;
|
||||||
case DMA_RESOURCE_REMOVED:
|
case DMA_RESOURCE_REMOVED:
|
||||||
net_dma_count--;
|
for (i = 0; i < NR_CPUS; i++)
|
||||||
net_dma_rebalance();
|
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;
|
break;
|
||||||
default:
|
default:
|
||||||
break;
|
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)
|
static int __init netdev_dma_register(void)
|
||||||
{
|
{
|
||||||
spin_lock_init(&net_dma_event_lock);
|
spin_lock_init(&net_dma.lock);
|
||||||
net_dma_client = dma_async_client_register(netdev_dma_event);
|
dma_cap_set(DMA_MEMCPY, net_dma.client.cap_mask);
|
||||||
if (net_dma_client == NULL)
|
dma_async_client_register(&net_dma.client);
|
||||||
return -ENOMEM;
|
dma_async_client_chan_request(&net_dma.client);
|
||||||
|
|
||||||
dma_async_client_chan_request(net_dma_client, num_online_cpus());
|
|
||||||
return 0;
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
Loading…
Reference in a new issue