[PATCH v1 01/10] PCI/P2PDMA: Remove redundant bus_offset from map state

Leon Romanovsky posted 10 patches 2 months ago
There is a newer version of this series
[PATCH v1 01/10] PCI/P2PDMA: Remove redundant bus_offset from map state
Posted by Leon Romanovsky 2 months ago
From: Leon Romanovsky <leonro@nvidia.com>

Remove the bus_off field from pci_p2pdma_map_state since it duplicates
information already available in the pgmap structure. The bus_offset
is only used in one location (pci_p2pdma_bus_addr_map) and is always
identical to pgmap->bus_offset.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/pci/p2pdma.c       | 1 -
 include/linux/pci-p2pdma.h | 3 +--
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index da5657a020074..274bb7bcc0bc5 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -1009,7 +1009,6 @@ void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state,
 {
 	state->pgmap = page_pgmap(page);
 	state->map = pci_p2pdma_map_type(state->pgmap, dev);
-	state->bus_off = to_p2p_pgmap(state->pgmap)->bus_offset;
 }
 
 /**
diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h
index 075c20b161d98..b502fc8b49bf9 100644
--- a/include/linux/pci-p2pdma.h
+++ b/include/linux/pci-p2pdma.h
@@ -146,7 +146,6 @@ enum pci_p2pdma_map_type {
 struct pci_p2pdma_map_state {
 	struct dev_pagemap *pgmap;
 	enum pci_p2pdma_map_type map;
-	u64 bus_off;
 };
 
 /* helper for pci_p2pdma_state(), do not use directly */
@@ -186,7 +185,7 @@ static inline dma_addr_t
 pci_p2pdma_bus_addr_map(struct pci_p2pdma_map_state *state, phys_addr_t paddr)
 {
 	WARN_ON_ONCE(state->map != PCI_P2PDMA_MAP_BUS_ADDR);
-	return paddr + state->bus_off;
+	return paddr + to_p2p_pgmap(state->pgmap)->bus_offsetf;
 }
 
 #endif /* _LINUX_PCI_P2P_H */
-- 
2.50.1
Re: [PATCH v1 01/10] PCI/P2PDMA: Remove redundant bus_offset from map state
Posted by Alex Williamson 1 month, 4 weeks ago
On Mon,  4 Aug 2025 16:00:36 +0300
Leon Romanovsky <leon@kernel.org> wrote:

> From: Leon Romanovsky <leonro@nvidia.com>
> 
> Remove the bus_off field from pci_p2pdma_map_state since it duplicates
> information already available in the pgmap structure. The bus_offset
> is only used in one location (pci_p2pdma_bus_addr_map) and is always
> identical to pgmap->bus_offset.
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/pci/p2pdma.c       | 1 -
>  include/linux/pci-p2pdma.h | 3 +--
>  2 files changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
> index da5657a020074..274bb7bcc0bc5 100644
> --- a/drivers/pci/p2pdma.c
> +++ b/drivers/pci/p2pdma.c
> @@ -1009,7 +1009,6 @@ void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state,
>  {
>  	state->pgmap = page_pgmap(page);
>  	state->map = pci_p2pdma_map_type(state->pgmap, dev);
> -	state->bus_off = to_p2p_pgmap(state->pgmap)->bus_offset;
>  }
>  
>  /**
> diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h
> index 075c20b161d98..b502fc8b49bf9 100644
> --- a/include/linux/pci-p2pdma.h
> +++ b/include/linux/pci-p2pdma.h
> @@ -146,7 +146,6 @@ enum pci_p2pdma_map_type {
>  struct pci_p2pdma_map_state {
>  	struct dev_pagemap *pgmap;
>  	enum pci_p2pdma_map_type map;
> -	u64 bus_off;
>  };
>  
>  /* helper for pci_p2pdma_state(), do not use directly */
> @@ -186,7 +185,7 @@ static inline dma_addr_t
>  pci_p2pdma_bus_addr_map(struct pci_p2pdma_map_state *state, phys_addr_t paddr)
>  {
>  	WARN_ON_ONCE(state->map != PCI_P2PDMA_MAP_BUS_ADDR);
> -	return paddr + state->bus_off;
> +	return paddr + to_p2p_pgmap(state->pgmap)->bus_offsetf;
>  }
>  
>  #endif /* _LINUX_PCI_P2P_H */

Looks like you're relying on this bogus code getting resolved in the
next patch...

In file included from kernel/dma/direct.c:16:
./include/linux/pci-p2pdma.h: In function ‘pci_p2pdma_bus_addr_map’:
./include/linux/pci-p2pdma.h:188:24: error: implicit declaration of function ‘to_p2p_pgmap’ [-Wimplicit-function-declaration]
  188 |         return paddr + to_p2p_pgmap(state->pgmap)->bus_offsetf;
      |                        ^~~~~~~~~~~~
./include/linux/pci-p2pdma.h:188:50: error: invalid type argument of ‘->’ (have ‘int’)
  188 |         return paddr + to_p2p_pgmap(state->pgmap)->bus_offsetf;
      |                                                  ^~
./include/linux/pci-p2pdma.h:189:1: error: control reaches end of non-void function [-Werror=return-type]
  189 | }
      | ^

to_p2p_pgmap() is a static function and struct pci_p2pdma_pagemap
doesn't have a bus_offsetf member.  Thanks,

Alex
Re: [PATCH v1 01/10] PCI/P2PDMA: Remove redundant bus_offset from map state
Posted by Leon Romanovsky 1 month ago
On Wed, Aug 06, 2025 at 02:58:25PM -0600, Alex Williamson wrote:
> On Mon,  4 Aug 2025 16:00:36 +0300
> Leon Romanovsky <leon@kernel.org> wrote:
> 
> > From: Leon Romanovsky <leonro@nvidia.com>
> > 
> > Remove the bus_off field from pci_p2pdma_map_state since it duplicates
> > information already available in the pgmap structure. The bus_offset
> > is only used in one location (pci_p2pdma_bus_addr_map) and is always
> > identical to pgmap->bus_offset.
> > 
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> > Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> > ---
> >  drivers/pci/p2pdma.c       | 1 -
> >  include/linux/pci-p2pdma.h | 3 +--
> >  2 files changed, 1 insertion(+), 3 deletions(-)
> > 
> > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
> > index da5657a020074..274bb7bcc0bc5 100644
> > --- a/drivers/pci/p2pdma.c
> > +++ b/drivers/pci/p2pdma.c
> > @@ -1009,7 +1009,6 @@ void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state,
> >  {
> >  	state->pgmap = page_pgmap(page);
> >  	state->map = pci_p2pdma_map_type(state->pgmap, dev);
> > -	state->bus_off = to_p2p_pgmap(state->pgmap)->bus_offset;
> >  }
> >  
> >  /**
> > diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h
> > index 075c20b161d98..b502fc8b49bf9 100644
> > --- a/include/linux/pci-p2pdma.h
> > +++ b/include/linux/pci-p2pdma.h
> > @@ -146,7 +146,6 @@ enum pci_p2pdma_map_type {
> >  struct pci_p2pdma_map_state {
> >  	struct dev_pagemap *pgmap;
> >  	enum pci_p2pdma_map_type map;
> > -	u64 bus_off;
> >  };
> >  
> >  /* helper for pci_p2pdma_state(), do not use directly */
> > @@ -186,7 +185,7 @@ static inline dma_addr_t
> >  pci_p2pdma_bus_addr_map(struct pci_p2pdma_map_state *state, phys_addr_t paddr)
> >  {
> >  	WARN_ON_ONCE(state->map != PCI_P2PDMA_MAP_BUS_ADDR);
> > -	return paddr + state->bus_off;
> > +	return paddr + to_p2p_pgmap(state->pgmap)->bus_offsetf;
> >  }
> >  
> >  #endif /* _LINUX_PCI_P2P_H */

Sorry for long time to reply, I waited to see what is going on with DMA
phys_vec basic series and together with my summer vacation, it took a
while.

> 
> Looks like you're relying on this bogus code getting resolved in the
> next patch...
> 
> In file included from kernel/dma/direct.c:16:
> ./include/linux/pci-p2pdma.h: In function ‘pci_p2pdma_bus_addr_map’:
> ./include/linux/pci-p2pdma.h:188:24: error: implicit declaration of function ‘to_p2p_pgmap’ [-Wimplicit-function-declaration]
>   188 |         return paddr + to_p2p_pgmap(state->pgmap)->bus_offsetf;
>       |                        ^~~~~~~~~~~~
> ./include/linux/pci-p2pdma.h:188:50: error: invalid type argument of ‘->’ (have ‘int’)
>   188 |         return paddr + to_p2p_pgmap(state->pgmap)->bus_offsetf;
>       |                                                  ^~
> ./include/linux/pci-p2pdma.h:189:1: error: control reaches end of non-void function [-Werror=return-type]
>   189 | }
>       | ^
> 
> to_p2p_pgmap() is a static function and struct pci_p2pdma_pagemap
> doesn't have a bus_offsetf member.  Thanks,

You are right, probably the best way to fix the error is simply squash
this change into the next patch.

Thanks



> 
> Alex
>