From 07f2211e4fbce6990722d78c4f04225da9c0e9cf Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Mon, 5 Jan 2009 17:14:31 -0700
Subject: 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>
---
include/linux/async_tx.h | 15 ---------------
1 file changed, 15 deletions(-)
(limited to 'include/linux/async_tx.h')
diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h
index 0f50d4cc436..1c816775f13 100644
--- a/include/linux/async_tx.h
+++ b/include/linux/async_tx.h
@@ -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,
--
cgit v1.2.3-70-g09d2
From 2ba05622b8b143b0c95968ba59bddfbd6d2f2559 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Tue, 6 Jan 2009 11:38:14 -0700
Subject: dmaengine: provide a common 'issue_pending_all' implementation
async_tx and net_dma each have open-coded versions of issue_pending_all,
so provide a common routine in dmaengine.
The implementation needs to walk the global device list, so implement
rcu to allow dma_issue_pending_all to run lockless. Clients protect
themselves from channel removal events by holding a dmaengine reference.
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
crypto/async_tx/async_tx.c | 12 ------------
drivers/dma/dmaengine.c | 27 ++++++++++++++++++++++++---
include/linux/async_tx.h | 2 +-
include/linux/dmaengine.h | 1 +
net/core/dev.c | 9 +--------
5 files changed, 27 insertions(+), 24 deletions(-)
(limited to 'include/linux/async_tx.h')
diff --git a/crypto/async_tx/async_tx.c b/crypto/async_tx/async_tx.c
index b88bb1f608f..2cdf7a0867b 100644
--- a/crypto/async_tx/async_tx.c
+++ b/crypto/async_tx/async_tx.c
@@ -45,18 +45,6 @@ static DEFINE_SPINLOCK(async_tx_lock);
static LIST_HEAD(async_tx_master_list);
-/* async_tx_issue_pending_all - start all transactions on all channels */
-void async_tx_issue_pending_all(void)
-{
- struct dma_chan_ref *ref;
-
- rcu_read_lock();
- list_for_each_entry_rcu(ref, &async_tx_master_list, node)
- ref->chan->device->device_issue_pending(ref->chan);
- rcu_read_unlock();
-}
-EXPORT_SYMBOL_GPL(async_tx_issue_pending_all);
-
static void
free_dma_chan_ref(struct rcu_head *rcu)
{
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 87a8cd4791e..418eca28d47 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -70,6 +70,7 @@
#include <linux/rcupdate.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
+#include <linux/rculist.h>
static DEFINE_MUTEX(dma_list_mutex);
static LIST_HEAD(dma_device_list);
@@ -365,6 +366,26 @@ struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
}
EXPORT_SYMBOL(dma_find_channel);
+/**
+ * dma_issue_pending_all - flush all pending operations across all channels
+ */
+void dma_issue_pending_all(void)
+{
+ struct dma_device *device;
+ struct dma_chan *chan;
+
+ WARN_ONCE(dmaengine_ref_count == 0,
+ "client called %s without a reference", __func__);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(device, &dma_device_list, global_node)
+ list_for_each_entry(chan, &device->channels, device_node)
+ if (chan->client_count)
+ device->device_issue_pending(chan);
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL(dma_issue_pending_all);
+
/**
* nth_chan - returns the nth channel of the given capability
* @cap: capability to match
@@ -490,7 +511,7 @@ void dma_async_client_register(struct dma_client *client)
err = dma_chan_get(chan);
if (err == -ENODEV) {
/* module removed before we could use it */
- list_del_init(&device->global_node);
+ list_del_rcu(&device->global_node);
break;
} else if (err)
pr_err("dmaengine: failed to get %s: (%d)\n",
@@ -635,7 +656,7 @@ int dma_async_device_register(struct dma_device *device)
goto err_out;
}
}
- list_add_tail(&device->global_node, &dma_device_list);
+ list_add_tail_rcu(&device->global_node, &dma_device_list);
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
@@ -677,7 +698,7 @@ void dma_async_device_unregister(struct dma_device *device)
struct dma_chan *chan;
mutex_lock(&dma_list_mutex);
- list_del(&device->global_node);
+ list_del_rcu(&device->global_node);
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h
index 1c816775f13..45f6297821b 100644
--- a/include/linux/async_tx.h
+++ b/include/linux/async_tx.h
@@ -59,7 +59,7 @@ enum async_tx_flags {
};
#ifdef CONFIG_DMA_ENGINE
-void async_tx_issue_pending_all(void);
+#define async_tx_issue_pending_all dma_issue_pending_all
#ifdef CONFIG_ARCH_HAS_ASYNC_TX_FIND_CHANNEL
#include <asm/async_tx.h>
#else
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index b466f02e243..57a43adfc39 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -471,6 +471,7 @@ 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);
+void dma_issue_pending_all(void);
/* --- Helper iov-locking functions --- */
diff --git a/net/core/dev.c b/net/core/dev.c
index 09c66a449da..e40b0d57f8f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2635,14 +2635,7 @@ out:
* There may not be any more sk_buffs coming right now, so push
* any pending DMA copies to hardware
*/
- if (!cpus_empty(net_dma.channel_mask)) {
- int chan_idx;
- for_each_cpu_mask_nr(chan_idx, net_dma.channel_mask) {
- struct dma_chan *chan = net_dma.channels[chan_idx];
- if (chan)
- dma_async_memcpy_issue_pending(chan);
- }
- }
+ dma_issue_pending_all();
#endif
return;
--
cgit v1.2.3-70-g09d2