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Date: Wed, 8 Apr 2009 02:22:29 +0900
From: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
To: galak@...nel.crashing.org
Cc: fujita.tomonori@....ntt.co.jp, beckyb@...nel.crashing.org,
linux-kernel@...r.kernel.org, mingo@...e.hu, jeremy@...p.org,
ian.campbell@...rix.com
Subject: Re: [PATCH 5/7] swiotlb: (re)Create swiotlb_unmap_single
On Tue, 7 Apr 2009 11:50:56 -0500
Kumar Gala <galak@...nel.crashing.org> wrote:
>
> On Apr 7, 2009, at 11:37 AM, FUJITA Tomonori wrote:
>
> > On Tue, 7 Apr 2009 10:32:20 -0500
> > Kumar Gala <galak@...nel.crashing.org> wrote:
> >
> >>
> >> On Apr 7, 2009, at 4:09 AM, FUJITA Tomonori wrote:
> >>
> >>> On Tue, 7 Apr 2009 01:34:44 -0500
> >>> Kumar Gala <galak@...nel.crashing.org> wrote:
> >>>
> >>>>
> >>>> On Apr 6, 2009, at 9:24 PM, FUJITA Tomonori wrote:
> >>>>
> >>>>> On Fri, 3 Apr 2009 20:56:47 -0500
> >>>>> Becky Bruce <beckyb@...nel.crashing.org> wrote:
> >>>>>
> >>>>>> This mirrors the current swiotlb_sync_single() setup
> >>>>>> where the swiotlb_unmap_single() function is static to this
> >>>>>> file and contains the logic required to determine if we need
> >>>>>> to call actual sync_single. Previously, swiotlb_unmap_page
> >>>>>> and swiotlb_unmap_sg were duplicating very similar code.
> >>>>>> The duplicated code has also been reformatted for
> >>>>>> readability.
> >>>>>>
> >>>>>> Note that the swiotlb_unmap_sg code was previously doing
> >>>>>> a complicated comparison to determine if an addresses needed
> >>>>>> to be unmapped where a simple is_swiotlb_buffer() call
> >>>>>> would have sufficed.
> >>>>>>
> >>>>>> Signed-off-by: Becky Bruce <beckyb@...nel.crashing.org>
> >>>>>> ---
> >>>>>> lib/swiotlb.c | 36 +++++++++++++++++++++++-------------
> >>>>>> 1 files changed, 23 insertions(+), 13 deletions(-)
> >>>>>>
> >>>>>> diff --git a/lib/swiotlb.c b/lib/swiotlb.c
> >>>>>> index af2ec25..602315b 100644
> >>>>>> --- a/lib/swiotlb.c
> >>>>>> +++ b/lib/swiotlb.c
> >>>>>
> >>>>> I don't think 'swiotlb_unmap_single' name is appropriate.
> >>>>>
> >>>>> swiotlb_unmap_single sounds like an exported function that IOMMUs
> >>>>> can
> >>>>> use (and it was) however it should not be.
> >>>>
> >>>> What do you suggest we call it? __swiotlb_unmap_single.
> >>>
> >>> I think that __swiotlb_unmap_single is better because the name
> >>> implies
> >>> that it's an internal function. It's fine by me.
> >>>
> >>> If it is odd that __swiotlb_unmap_single() is just a wrapper
> >>> function
> >>> of unmap_single(), which does the real job to unmap a dma mapping,
> >>> it
> >>> might be another possible option to rename unmap_single to
> >>> do_unamp_single and use unmap_single.
> >>
> >> I think you lost me here. I'd prefer to just use
> >> __swiotlb_unmap_single at this point and get this code into the tree
> >> and work on such renaming after the fact (if that's ok).
> >
> > If you are rushing to merge this right now, the original patchset is
> > fine by me (I thought that you missed this merge window). I'll rename
> > it later.
>
> We probably did, but one can never tell with these things. It seemed
> like Ingo merged and pushed some swiotlb changes late in the game for .
> 29
Well, merging patches that have not been tested linux-next late is
what we should not do, I guess. I like to see Becky's patch in 2.6.30
because I have some swiotlb changes for 2.6.31 though.
> I'm still not clear on what you are suggesting... "rename unmap_single
> to do_unamp_single and use unmap_single".
This can be applied after Becky's patchset.
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 1c86553..bffe6d7 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -482,7 +482,7 @@ found:
* dma_addr is the kernel virtual address of the bounce buffer to unmap.
*/
static void
-unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
+do_unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
{
unsigned long flags;
int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
@@ -591,7 +591,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
(unsigned long long)dev_addr);
/* DMA_TO_DEVICE to avoid memcpy in unmap_single */
- unmap_single(hwdev, ret, size, DMA_TO_DEVICE);
+ do_unmap_single(hwdev, ret, size, DMA_TO_DEVICE);
return NULL;
}
*dma_handle = dev_addr;
@@ -608,7 +608,7 @@ swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
free_pages((unsigned long) vaddr, get_order(size));
else
/* DMA_TO_DEVICE to avoid memcpy in unmap_single */
- unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE);
+ do_unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE);
}
EXPORT_SYMBOL(swiotlb_free_coherent);
@@ -688,16 +688,15 @@ EXPORT_SYMBOL_GPL(swiotlb_map_page);
* After this call, reads by the cpu to the buffer are guaranteed to see
* whatever the device wrote there.
*/
-static void
-swiotlb_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
- size_t size, int dir)
+static void unmap_single(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, int dir)
{
char *dma_addr = swiotlb_bus_to_virt(hwdev, dev_addr);
BUG_ON(dir == DMA_NONE);
if (is_swiotlb_buffer(dma_addr)) {
- unmap_single(hwdev, dma_addr, size, dir);
+ do_unmap_single(hwdev, dma_addr, size, dir);
return;
}
@@ -711,7 +710,7 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
- swiotlb_unmap_single(hwdev, dev_addr, size, dir);
+ unmap_single(hwdev, dev_addr, size, dir);
}
EXPORT_SYMBOL_GPL(swiotlb_unmap_page);
@@ -864,8 +863,7 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
BUG_ON(dir == DMA_NONE);
for_each_sg(sgl, sg, nelems, i)
- swiotlb_unmap_single(hwdev, sg->dma_address, sg->dma_length,
- dir);
+ unmap_single(hwdev, sg->dma_address, sg->dma_length, dir);
}
EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
--
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