On Thu, Sep 4, 2008 at 4:24 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> On Thu, Sep 4, 2008 at 2:19 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>> On Thu, 4 Sep 2008 01:43:51 +0400
>> Ilya Yanok <yanok@xxxxxxxxxxx> wrote:
>>
>>> From: Yuri Tikhonov <yur@xxxxxxxxxxx>
>>>
>>> Should clear the next pointer of the TX if we are sure that the
>>> next TX (say NXT) will be submitted to the channel too. Overwise,
>>> we break the chain of descriptors, because we lose the information
>>> about the next descriptor to run. So next time, when invoke
>>> async_tx_run_dependencies() with TX, it's TX->next will be NULL, and
>>> NXT will be never submitted.
>>>
>>> Signed-off-by: Yuri Tikhonov <yur@xxxxxxxxxxx>
>>
>> This patch should include your signed-off-by: as well. Because you
>> were on the delivery path, as described in
>> Documentation/SubmittingPatches, section 12.
>>
>
> Yes, Ilya once I have your signed-off-by I will push this to Linus and
> -stable. As far as impact for in-tree drivers: iop13xx by is immune,
> iop3xx can hit this, and it looks like the orion5x implementation is
> immune since copy and xor are available on the same channel.
>
Please also take a look at this cleanup patch that I will queue for
.28. I think it makes things easier to read let me know if you
disagree.
---gmail mangled patch follows--->
async_tx: make async_tx_run_dependencies() easier to read
From: Dan Williams <dan.j.williams@xxxxxxxxx>
* Rename 'next' to 'dep'
* Move the channel switch check inside the loop to simplify
termination
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
crypto/async_tx/async_tx.c | 36 +++++++++++++++++-------------------
1 files changed, 17 insertions(+), 19 deletions(-)
diff --git a/crypto/async_tx/async_tx.c b/crypto/async_tx/async_tx.c
index e8362c1..b833cca 100644
--- a/crypto/async_tx/async_tx.c
+++ b/crypto/async_tx/async_tx.c
@@ -115,34 +115,32 @@ EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
* (start) dependent operations on their target channel
* @tx: transaction with dependencies
*/
-void
-async_tx_run_dependencies(struct dma_async_tx_descriptor *tx)
+void async_tx_run_dependencies(struct dma_async_tx_descriptor *tx)
{
- struct dma_async_tx_descriptor *next = tx->next;
+ struct dma_async_tx_descriptor *dep = tx->next;
+ struct dma_async_tx_descriptor *dep_next;
struct dma_chan *chan;
- if (!next)
+ if (dep)
+ chan = dep->chan;
+ else
return;
- tx->next = NULL;
- chan = next->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
*/
- while (next && next->chan == chan) {
- struct dma_async_tx_descriptor *_next;
-
- spin_lock_bh(&next->lock);
- next->parent = NULL;
- _next = next->next;
- if (_next && _next->chan == chan)
- next->next = NULL;
- spin_unlock_bh(&next->lock);
-
- next->tx_submit(next);
- next = _next;
+ 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);
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
