Steven Rostedt wrote:
> On Fri, 16 Nov 2007, Nelson, Shannon wrote:
>> first->async_tx.phys;
>>> - __list_splice(&new_chain, ioat_chan->used_desc.prev);
>>> + list_splice_tail(&new_chain, ioat_chan->used_desc.prev);
>>>
>> NAK.
>>
>> These functions do insertions differently. The 'prev' is pointing to
>> the last valid descriptor in the queue and you really want to get the
>> new_chain stuck on after this. Your list_splice_tail() will insert the
>> new_chain just before it which will muck up the order of the DMA
>> requests.
>>
>> You might have more success with
>> list_splice_tail(&new_chain, ioat_chan->used_desc);
>> where used_desc points to the whole list, rather than using the .prev
>> pointer to a specific node.
>>
>> Please copy me on future ioatdma related comments.
>>
>
> And people wonder why we post RT related patches to LKML. This is exactly
> why!
>
> Thanks for the response Shannon!
>
> -- Steve
>
Hi
I've tried this change, but it still don't compile. So I propose this patch.
regards,
trem
------------------------
Index: linux-2.6.23/drivers/dma/ioat_dma.c
===================================================================
--- linux-2.6.23.orig/drivers/dma/ioat_dma.c
+++ linux-2.6.23/drivers/dma/ioat_dma.c
@@ -244,7 +244,7 @@ static dma_cookie_t ioat_tx_submit(struc
/* write address into NextDescriptor field of last desc in chain */
to_ioat_desc(ioat_chan->used_desc.prev)->hw->next =
first->async_tx.phys;
- __list_splice(&new_chain, ioat_chan->used_desc.prev);
+ list_splice_tail(&new_chain, &ioat_chan->used_desc);
ioat_chan->pending += desc_count;
if (ioat_chan->pending >= 4) {
-
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