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dmaengine: remove dependency on async_tx

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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>
This commit is contained in:
Dan Williams 2009-01-05 17:14:31 -07:00
parent 28405d8d9c
commit 07f2211e4f
7 changed files with 95 additions and 96 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

75
crypto/async_tx/async_tx.c
View File

@ -72,81 +72,6 @@ void async_tx_issue_pending_all(void)
}
EXPORT_SYMBOL_GPL(async_tx_issue_pending_all);
/* dma_wait_for_async_tx - spin wait for a transcation to complete
* @tx: transaction to wait on
*/
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;
/* 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);
/* async_tx_run_dependencies - helper routine for dma drivers to process
* (start) dependent operations on their target channel
* @tx: transaction with dependencies
*/
void async_tx_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(async_tx_run_dependencies);
static void
free_dma_chan_ref(struct rcu_head *rcu)
{

2
drivers/dma/Kconfig
View File

@ -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.

84
drivers/dma/dmaengine.c
View File

@ -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);

3
drivers/dma/iop-adma.c
View File

@ -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;
}

3
drivers/dma/mv_xor.c
View File

@ -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;
}

15
include/linux/async_tx.h
View File

@ -60,8 +60,6 @@ enum async_tx_flags {
#ifdef CONFIG_DMA_ENGINE
void async_tx_issue_pending_all(void);
enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
void async_tx_run_dependencies(struct dma_async_tx_descriptor *tx);
#ifdef CONFIG_ARCH_HAS_ASYNC_TX_FIND_CHANNEL
#include <asm/async_tx.h>
#else
@ -77,19 +75,6 @@ static inline void async_tx_issue_pending_all(void)
do { } while (0);
}
static inline enum dma_status
dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
{
return DMA_SUCCESS;
}
static inline void
async_tx_run_dependencies(struct dma_async_tx_descriptor *tx,
struct dma_chan *host_chan)
{
do { } while (0);
}
static inline struct dma_chan *
async_tx_find_channel(struct dma_async_tx_descriptor *depend_tx,
enum dma_transaction_type tx_type, struct page **dst, int dst_count,

9
include/linux/dmaengine.h
View File

@ -475,11 +475,20 @@ static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
}
enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie);
#ifdef CONFIG_DMA_ENGINE
enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
#else
static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
{
return DMA_SUCCESS;
}
#endif
/* --- DMA device --- */
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);
/* --- Helper iov-locking functions --- */