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authorDan Williams <dan.j.williams@intel.com>2009-01-05 17:14:31 -0700
committerDan Williams <dan.j.williams@intel.com>2009-01-05 18:10:19 -0700
commit07f2211e4fbce6990722d78c4f04225da9c0e9cf (patch)
tree51934e20a334e93c8c399d2e6375f264551e9bc3 /drivers
parent28405d8d9ce05f5bd869ef8b48da5086f9527d73 (diff)
dmaengine: remove dependency on async_tx
async_tx.ko is a consumer of dma channels. A circular dependency arises if modules in drivers/dma rely on common code in async_tx.ko. It prevents either module from being unloaded. Move dma_wait_for_async_tx and async_tx_run_dependencies to dmaeninge.o where they should have been from the beginning. Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/dma/Kconfig2
-rw-r--r--drivers/dma/dmaengine.c84
-rw-r--r--drivers/dma/iop-adma.c3
-rw-r--r--drivers/dma/mv_xor.c3
4 files changed, 86 insertions, 6 deletions
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 904e57558bb..e34b0642081 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -33,7 +33,6 @@ config INTEL_IOATDMA
config INTEL_IOP_ADMA
tristate "Intel IOP ADMA support"
depends on ARCH_IOP32X || ARCH_IOP33X || ARCH_IOP13XX
- select ASYNC_CORE
select DMA_ENGINE
help
Enable support for the Intel(R) IOP Series RAID engines.
@@ -59,7 +58,6 @@ config FSL_DMA
config MV_XOR
bool "Marvell XOR engine support"
depends on PLAT_ORION
- select ASYNC_CORE
select DMA_ENGINE
---help---
Enable support for the Marvell XOR engine.
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 65799651737..b9008932a8f 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -626,6 +626,90 @@ void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
}
EXPORT_SYMBOL(dma_async_tx_descriptor_init);
+/* dma_wait_for_async_tx - spin wait for a transaction to complete
+ * @tx: in-flight transaction to wait on
+ *
+ * This routine assumes that tx was obtained from a call to async_memcpy,
+ * async_xor, async_memset, etc which ensures that tx is "in-flight" (prepped
+ * and submitted). Walking the parent chain is only meant to cover for DMA
+ * drivers that do not implement the DMA_INTERRUPT capability and may race with
+ * the driver's descriptor cleanup routine.
+ */
+enum dma_status
+dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
+{
+ enum dma_status status;
+ struct dma_async_tx_descriptor *iter;
+ struct dma_async_tx_descriptor *parent;
+
+ if (!tx)
+ return DMA_SUCCESS;
+
+ WARN_ONCE(tx->parent, "%s: speculatively walking dependency chain for"
+ " %s\n", __func__, dev_name(&tx->chan->dev));
+
+ /* poll through the dependency chain, return when tx is complete */
+ do {
+ iter = tx;
+
+ /* find the root of the unsubmitted dependency chain */
+ do {
+ parent = iter->parent;
+ if (!parent)
+ break;
+ else
+ iter = parent;
+ } while (parent);
+
+ /* there is a small window for ->parent == NULL and
+ * ->cookie == -EBUSY
+ */
+ while (iter->cookie == -EBUSY)
+ cpu_relax();
+
+ status = dma_sync_wait(iter->chan, iter->cookie);
+ } while (status == DMA_IN_PROGRESS || (iter != tx));
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
+
+/* dma_run_dependencies - helper routine for dma drivers to process
+ * (start) dependent operations on their target channel
+ * @tx: transaction with dependencies
+ */
+void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
+{
+ struct dma_async_tx_descriptor *dep = tx->next;
+ struct dma_async_tx_descriptor *dep_next;
+ struct dma_chan *chan;
+
+ if (!dep)
+ return;
+
+ chan = dep->chan;
+
+ /* keep submitting up until a channel switch is detected
+ * in that case we will be called again as a result of
+ * processing the interrupt from async_tx_channel_switch
+ */
+ for (; dep; dep = dep_next) {
+ spin_lock_bh(&dep->lock);
+ dep->parent = NULL;
+ dep_next = dep->next;
+ if (dep_next && dep_next->chan == chan)
+ dep->next = NULL; /* ->next will be submitted */
+ else
+ dep_next = NULL; /* submit current dep and terminate */
+ spin_unlock_bh(&dep->lock);
+
+ dep->tx_submit(dep);
+ }
+
+ chan->device->device_issue_pending(chan);
+}
+EXPORT_SYMBOL_GPL(dma_run_dependencies);
+
static int __init dma_bus_init(void)
{
mutex_init(&dma_list_mutex);
diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c
index 6be31726220..be9ea9f8880 100644
--- a/drivers/dma/iop-adma.c
+++ b/drivers/dma/iop-adma.c
@@ -24,7 +24,6 @@
#include <linux/init.h>
#include <linux/module.h>
-#include <linux/async_tx.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/spinlock.h>
@@ -116,7 +115,7 @@ iop_adma_run_tx_complete_actions(struct iop_adma_desc_slot *desc,
}
/* run dependent operations */
- async_tx_run_dependencies(&desc->async_tx);
+ dma_run_dependencies(&desc->async_tx);
return cookie;
}
diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
index bcda1742641..3f46df3390c 100644
--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -18,7 +18,6 @@
#include <linux/init.h>
#include <linux/module.h>
-#include <linux/async_tx.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/spinlock.h>
@@ -340,7 +339,7 @@ mv_xor_run_tx_complete_actions(struct mv_xor_desc_slot *desc,
}
/* run dependent operations */
- async_tx_run_dependencies(&desc->async_tx);
+ dma_run_dependencies(&desc->async_tx);
return cookie;
}