path: root/crypto/async_tx/async_tx.c
diff options
authorDan Williams <dan.j.williams@intel.com>2009-07-14 12:19:02 -0700
committerDan Williams <dan.j.williams@intel.com>2009-08-29 19:09:27 -0700
commit95475e57113c66aac7583925736ed2e2d58c990d (patch)
tree933aa0ca3bffef5b1457c516fbe3e8690b4c4cb1 /crypto/async_tx/async_tx.c
parentaf1f951eb6ef27b01cbfb3f6c21b770af4368a6d (diff)
async_tx: remove walk of tx->parent chain in dma_wait_for_async_tx
We currently walk the parent chain when waiting for a given tx to complete however this walk may race with the driver cleanup routine. The routines in async_raid6_recov.c may fall back to the synchronous path at any point so we need to be prepared to call async_tx_quiesce() (which calls dma_wait_for_async_tx). To remove the ->parent walk we guarantee that every time a dependency is attached ->issue_pending() is invoked, then we can simply poll the initial descriptor until completion. This also allows for a lighter weight 'issue pending' implementation as there is no longer a requirement to iterate through all the channels' ->issue_pending() routines as long as operations have been submitted in an ordered chain. async_tx_issue_pending() is added for this case. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'crypto/async_tx/async_tx.c')
1 files changed, 7 insertions, 6 deletions
diff --git a/crypto/async_tx/async_tx.c b/crypto/async_tx/async_tx.c
index 6e37ad3f441..60615fedcf5 100644
--- a/crypto/async_tx/async_tx.c
+++ b/crypto/async_tx/async_tx.c
@@ -77,8 +77,8 @@ static void
async_tx_channel_switch(struct dma_async_tx_descriptor *depend_tx,
struct dma_async_tx_descriptor *tx)
- struct dma_chan *chan;
- struct dma_device *device;
+ struct dma_chan *chan = depend_tx->chan;
+ struct dma_device *device = chan->device;
struct dma_async_tx_descriptor *intr_tx = (void *) ~0;
/* first check to see if we can still append to depend_tx */
@@ -90,11 +90,11 @@ async_tx_channel_switch(struct dma_async_tx_descriptor *depend_tx,
- if (!intr_tx)
+ /* attached dependency, flush the parent channel */
+ if (!intr_tx) {
+ device->device_issue_pending(chan);
- chan = depend_tx->chan;
- device = chan->device;
+ }
/* see if we can schedule an interrupt
* otherwise poll for completion
@@ -128,6 +128,7 @@ async_tx_channel_switch(struct dma_async_tx_descriptor *depend_tx,
+ device->device_issue_pending(chan);
} else {
if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
panic("%s: DMA_ERROR waiting for depend_tx\n",