Re: [PATCH] sparc: iommu/pci_sun4v: fix page alignment in dma mapping

[Stian Halseth]

On Tue, 2026-02-17 at 19:52 +0200, Leon Romanovsky wrote:
> 
> 
> On Tue, Feb 17, 2026, at 19:33, Stian Halseth wrote:
> > Hi Leon,
> > 
> > 
> > On Tue, 2026-02-17 at 19:25 +0200, Leon Romanovsky wrote:
> > > 
> > > 
> > > On Tue, Feb 17, 2026, at 19:16, John Paul Adrian Glaubitz wrote:
> > > > Hi Stian,
> > > > 
> > > > On Tue, 2026-02-17 at 17:48 +0100, Stian Halseth wrote:
> > > > > Thanks for the review and suggestions.
> > > > > 
> > > > > On Tue, 2026-02-17 at 17:38 +0100, John Paul Adrian Glaubitz
> > > > > wrote:
> > > > > > Hi Stian,
> > > > > > 
> > > > > > please rephrase the subject to:
> > > > > > 
> > > > > >  sparc: Fix page alignment in dma mapping
> > > > > > 
> > > > > > Your patch is not specific to sun4v but also fixes generic
> > > > > > sparc
> > > > > > code,
> > > > > > so you should remove the part "iommu/pci_sun4v:" from the
> > > > > > subject.
> > > > > > 
> > > > > Understood — I will update the patch subject as suggested.
> > > > > > On Tue, 2026-02-17 at 17:21 +0100, stian@xxxxxx wrote:
> > > > > > > From: Stian Halseth <stian@xxxxxx>
> > > > > > > 
> > > > > > > 'phys' may include an offset within the page, while
> > > > > > > 'base_paddr' is
> > > > > > > already page-aligned.
> > > > > > > 
> > > > > > > This caused incorrect DMA mapping in dma_4u_map_phys and
> > > > > > > dma_4v_map_phys.
> > > > > > > 
> > > > > > > Fix both functions by masking phys with IO_PAGE_MASK or
> > > > > > > subtracting
> > > > > > > the page offset.
> > > > > > 
> > > > > > Please remove the newlines between your sentences, they're
> > > > > > not
> > > > > > necessary
> > > > > > and also trim the lines at 80 columns.
> > > > > 
> > > > > Will do — I’ll reformat the commit message to 80-column lines
> > > > > and remove extra newlines.
> > > > 
> > > > Perfect! I have nothing to add. Let's have Andreas review your
> > > > patch ;-).
> > > 
> > > Please add Fixes line, so the patch will be taken to stable@ in
> > > automatic way.
> > I currently have:
> > Fixes: 38c0d0ebf520 ("sparc: Use physical address DMA mapping")
> > 
> > Is this sufficient, or do I need to add something else?
> 
> Ohh, you added extra line between signed-of-by and fixes line.
> 
> Just remove that extra blank line.
> 
> Thanks 
Ah, I see what you mean now. There _was_ an extra line in the first
submitted patch [1]. This is not the case in the updated patch v2 [2],
submitted Tue, 17 Feb 2026 17:21:13 +0100.

Let me know if there's still an issue with the latest patch, or if I've
made a mistake when submitting it. My first patch to LKML, sorry about
the extra work :)

> 
> > > 
> > > Thanks 
> > > 
> > > > 
> > > > Adrian
> > > > 
> > > > -- 
> > > >  .''`.  John Paul Adrian Glaubitz
> > > > : :' :  Debian Developer
> > > > `. `'   Physicist
> > > >   `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913
> > 
> > -- 
> > Best regards
> > Stian Halseth
> > ​

[1] https://lkml.org/lkml/2026/2/17/845
[2] https://lkml.org/lkml/2026/2/17/908

-- 
Best regards
Stian Halseth
​