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Date: Fri, 6 Mar 2009 20:07:14 +0900
From: Atsushi Nemoto <anemo@....ocn.ne.jp>
To: Dan Williams <dan.j.williams@...el.com>
Cc: Maciej Sosnowski <maciej.sosnowski@...el.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH] dmaengine: Add privatecnt to revert DMA_PRIVATE propery
Currently dma_request_channel() set DMA_PRIVATE capability but never
clear it. So if a public channel was once grabbed by
dma_request_channel(), the device stay PRIVATE forever. Add
privatecnt member to dma_device to correctly revert it.
Signed-off-by: Atsushi Nemoto <anemo@....ocn.ne.jp>
---
drivers/dma/dmaengine.c | 8 ++++++++
include/linux/dmaengine.h | 9 +++++++++
2 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 280a9d2..14be8fa 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -507,6 +507,7 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v
* published in the general-purpose allocator
*/
dma_cap_set(DMA_PRIVATE, device->cap_mask);
+ device->privatecnt++;
err = dma_chan_get(chan);
if (err == -ENODEV) {
@@ -518,6 +519,8 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v
dma_chan_name(chan), err);
else
break;
+ if (--device->privatecnt == 0)
+ dma_cap_clear(DMA_PRIVATE, device->cap_mask);
chan->private = NULL;
chan = NULL;
}
@@ -537,6 +540,9 @@ void dma_release_channel(struct dma_chan *chan)
WARN_ONCE(chan->client_count != 1,
"chan reference count %d != 1\n", chan->client_count);
dma_chan_put(chan);
+ /* drop PRIVATE cap enabled by __dma_request_channel() */
+ if (--chan->device->privatecnt == 0)
+ dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
chan->private = NULL;
mutex_unlock(&dma_list_mutex);
}
@@ -701,6 +707,8 @@ int dma_async_device_register(struct dma_device *device)
}
}
list_add_tail_rcu(&device->global_node, &dma_device_list);
+ if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+ chan->device->privatecnt++; /* Always private */
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index f041384..f834fa1 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -209,6 +209,7 @@ struct dma_async_tx_descriptor {
/**
* struct dma_device - info on the entity supplying DMA services
* @chancnt: how many DMA channels are supported
+ * @privatecnt: how many DMA channels are requested by dma_request_channel
* @channels: the list of struct dma_chan
* @global_node: list_head for global dma_device_list
* @cap_mask: one or more dma_capability flags
@@ -232,6 +233,7 @@ struct dma_async_tx_descriptor {
struct dma_device {
unsigned int chancnt;
+ unsigned int privatecnt;
struct list_head channels;
struct list_head global_node;
dma_cap_mask_t cap_mask;
@@ -342,6 +344,13 @@ __dma_cap_set(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
set_bit(tx_type, dstp->bits);
}
+#define dma_cap_clear(tx, mask) __dma_cap_clear((tx), &(mask))
+static inline void
+__dma_cap_clear(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
+{
+ clear_bit(tx_type, dstp->bits);
+}
+
#define dma_cap_zero(mask) __dma_cap_zero(&(mask))
static inline void __dma_cap_zero(dma_cap_mask_t *dstp)
{
--
1.5.6.3
--
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