2007-11-16 11:57:43

by Sven-Thorsten Dietrich

[permalink] [raw]
Subject: [PATCH][RT] 2.6.24-rc2-rt1 drivers/dma/ioat_dma.c compile fix

Compile fix for new code in -rc2.

I'm not positive about the insertion point...

Subject: compile error fix (needs review)

RT changes __list_splice to require prev and next pointers.

This changes the use in the new code to list_splice_tail,
but the optimal insertion point needs to be analyzed.

Signed-off-by: Sven-Thorsten Dietrich <[email protected]>

---
drivers/dma/ioat_dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

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.prev);

ioat_chan->pending += desc_count;
if (ioat_chan->pending >= 4) {



2007-11-16 17:07:39

by Shannon Nelson

[permalink] [raw]
Subject: Re: [PATCH][RT] 2.6.24-rc2-rt1 drivers/dma/ioat_dma.c compile fix

On Nov 16, 2007 3:57 AM, Sven-Thorsten Dietrich <[email protected]>
wrote:
> Compile fix for new code in -rc2.
>
> I'm not positive about the insertion point...
>
> Subject: compile error fix (needs review)
>
> RT changes __list_splice to require prev and next pointers.
>
> This changes the use in the new code to list_splice_tail,
> but the optimal insertion point needs to be analyzed.
>
> Signed-off-by: Sven-Thorsten Dietrich <[email protected]>
>
> ---
> drivers/dma/ioat_dma.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> 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.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.

Thanks,
sln
--
======================================================================
Mr. Shannon Nelson LAN Access Division, Intel Corp.
[email protected] I don't speak for Intel
(503) 712-7659 Parents can't afford to be squeamish.

2007-11-16 17:16:53

by Steven Rostedt

[permalink] [raw]
Subject: Re: [PATCH][RT] 2.6.24-rc2-rt1 drivers/dma/ioat_dma.c compile fix


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

2007-11-20 22:10:27

by Philippe Reynes

[permalink] [raw]
Subject: Re: [PATCH][RT] 2.6.24-rc2-rt1 drivers/dma/ioat_dma.c compile fix

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) {

2007-12-15 03:56:32

by Sven-Thorsten Dietrich

[permalink] [raw]
Subject: [PATCH][RT] 2.6.24-rc5-rt1 drivers/dma/ioat_dma.c compile fix

Hi Steve,

looks like this patch didn't make it into 2.6.23-rc5-rt1.

I refreshed Trem's final version - please review and include in the next
RT release.

Thanks

Sven



On Tue, 2007-11-20 at 23:09 +0100, trem wrote:
> 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.
> >>
> >

> Hi
>
> I've tried this change, but it still don't compile. So I propose this patch.
>
> regards,
> trem


From: trem <[email protected]>
Subject: Re: [PATCH][RT] 2.6.24-rc2-rt1 drivers/dma/ioat_dma.c compile fix

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

Acked-by: Sven-Thorsten Dietrich <[email protected]>

------------------------

---
drivers/dma/ioat_dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

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
@@ -260,7 +260,7 @@ static dma_cookie_t ioat1_tx_submit(stru
/* 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(&new_chain, &ioat_chan->used_desc);

ioat_chan->dmacount += desc_count;
ioat_chan->pending += desc_count;


2007-12-15 14:05:45

by Steven Rostedt

[permalink] [raw]
Subject: Re: [PATCH][RT] 2.6.24-rc5-rt1 drivers/dma/ioat_dma.c compile fix



On Fri, 14 Dec 2007, Sven-Thorsten Dietrich wrote:

> Hi Steve,
>
> looks like this patch didn't make it into 2.6.23-rc5-rt1.
>
> I refreshed Trem's final version - please review and include in the next
> RT release.
>

Sven,

Thanks, I'll take a look at it and if I don't find any issues I'll add it
to -rt2 (or rc6-rt1 which ever comes first).

-- Steve