dmaengine: centralize channel allocation, introduce dma_find_channel
Allowing multiple clients to each define their own channel allocation
scheme quickly leads to a pathological situation. For memory-to-memory
offload all clients can share a central allocator.
This simply moves the existing async_tx allocator to dmaengine with
minimal fixups:
* async_tx.c:get_chan_ref_by_cap --> dmaengine.c:nth_chan
* async_tx.c:async_tx_rebalance --> dmaengine.c:dma_channel_rebalance
* split out common code from async_tx.c:__async_tx_find_channel -->
dma_find_channel
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index d18d37d..b466f02 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -182,6 +182,7 @@
* @device_node: used to add this to the device chan list
* @local: per-cpu pointer to a struct dma_chan_percpu
* @client-count: how many clients are using this channel
+ * @table_count: number of appearances in the mem-to-mem allocation table
*/
struct dma_chan {
struct dma_device *device;
@@ -198,6 +199,7 @@
struct list_head device_node;
struct dma_chan_percpu *local;
int client_count;
+ int table_count;
};
#define to_dma_chan(p) container_of(p, struct dma_chan, dev)
@@ -468,6 +470,7 @@
int dma_async_device_register(struct dma_device *device);
void dma_async_device_unregister(struct dma_device *device);
void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
+struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type);
/* --- Helper iov-locking functions --- */