Adds the following macros:
DECLARE_DMA_UNMAP_ADDR(ADDR_NAME)
DECLARE_DMA_UNMAP_LEN(LEN_NAME)
dma_unmap_addr(PTR, ADDR_NAME)
dma_unmap_addr_set(PTR, ADDR_NAME, VAL)
dma_unmap_len(PTR, LEN_NAME)
dma_unmap_len_set(PTR, LEN_NAME, VAL)
The API corresponds to the pci_unmap state API. We'll move to this new
generic API from the PCI specific API in the long term. As
include/asm-generic/pci-dma-compat.h does, the pci_unmap API simply
calls the new generic API for some time.
Signed-off-by: FUJITA Tomonori <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Jesse Barnes <[email protected]>
Cc: Arnd Bergmann <[email protected]>
---
Documentation/DMA-API.txt | 60 +++++++++++++++++++++++++++++++++++++++++++
include/linux/dma-mapping.h | 16 +++++++++++
include/linux/pci-dma.h | 21 ++++----------
3 files changed, 82 insertions(+), 15 deletions(-)
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 364a6cb..bd34a62 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -472,6 +472,66 @@ void whizco_dma_map_sg_attrs(struct device *dev, dma_addr_t dma_addr,
....
+Part Ie - Optimizing Unmap State Space Consumption
+--------------------------------
+
+On some platforms, dma_unmap_{single,page}() is simply a nop.
+Therefore, keeping track of the mapping address and length is a waste
+of space. Instead of filling your drivers up with ifdefs and the like
+to "work around" this (which would defeat the whole purpose of a
+portable API) the following facilities are provided.
+
+Actually, instead of describing the macros one by one, we'll
+transform some example code.
+
+1) Use DECLARE_DMA_UNMAP_{ADDR,LEN} in state saving structures.
+ Example, before:
+
+ struct ring_state {
+ struct sk_buff *skb;
+ dma_addr_t mapping;
+ __u32 len;
+ };
+
+ after:
+
+ struct ring_state {
+ struct sk_buff *skb;
+ DECLARE_DMA_UNMAP_ADDR(mapping)
+ DECLARE_DMA_UNMAP_LEN(len)
+ };
+
+NOTE: DO NOT put a semicolon at the end of the DECLARE_*() macro.
+
+2) Use dma_unmap_{addr,len}_set to set these values.
+ Example, before:
+
+ ringp->mapping = FOO;
+ ringp->len = BAR;
+
+ after:
+
+ dma_unmap_addr_set(ringp, mapping, FOO);
+ dma_unmap_len_set(ringp, len, BAR);
+
+3) Use dma_unmap_{addr,len} to access these values.
+ Example, before:
+
+ dma_unmap_single(dev, ringp->mapping, ringp->len,
+ DMA_FROM_DEVICE);
+
+ after:
+
+ dma_unmap_single(dev,
+ dma_unmap_addr(ringp, mapping),
+ dma_unmap_len(ringp, len),
+ DMA_FROM_DEVICE);
+
+It really should be self-explanatory. We treat the ADDR and LEN
+separately, because it is possible for an implementation to only
+need the address in order to perform the unmap operation.
+
+
Part II - Advanced dma_ usage
-----------------------------
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 91b7618..86e7dc3 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -232,4 +232,20 @@ struct dma_attrs;
#endif /* CONFIG_HAVE_DMA_ATTRS */
+#ifdef CONFIG_NEED_DMA_MAP_STATE
+#define DECLARE_DMA_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME;
+#define DECLARE_DMA_UNMAP_LEN(LEN_NAME) __u32 LEN_NAME;
+#define dma_unmap_addr(PTR, ADDR_NAME) ((PTR)->ADDR_NAME)
+#define dma_unmap_addr_set(PTR, ADDR_NAME, VAL) (((PTR)->ADDR_NAME) = (VAL))
+#define dma_unmap_len(PTR, LEN_NAME) ((PTR)->LEN_NAME)
+#define dma_unmap_len_set(PTR, LEN_NAME, VAL) (((PTR)->LEN_NAME) = (VAL))
+#else
+#define DECLARE_DMA_MAP_ADDR(ADDR_NAME)
+#define DECLARE_DMA_UNMAP_LEN(LEN_NAME)
+#define dma_unmap_addr(PTR, ADDR_NAME) (0)
+#define dma_unmap_addr_set(PTR, ADDR_NAME, VAL) do { } while (0)
+#define dma_unmap_len(PTR, LEN_NAME) (0)
+#define dma_unmap_len_set(PTR, LEN_NAME, VAL) do { } while (0)
+#endif
+
#endif
diff --git a/include/linux/pci-dma.h b/include/linux/pci-dma.h
index cfd63ab..235a61e 100644
--- a/include/linux/pci-dma.h
+++ b/include/linux/pci-dma.h
@@ -1,20 +1,11 @@
#ifndef _LINUX_PCI_DMA_H
#define _LINUX_PCI_DMA_H
-#ifdef CONFIG_NEED_DMA_MAP_STATE
-#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME;
-#define DECLARE_PCI_UNMAP_LEN(LEN_NAME) __u32 LEN_NAME;
-#define pci_unmap_addr(PTR, ADDR_NAME) ((PTR)->ADDR_NAME)
-#define pci_unmap_addr_set(PTR, ADDR_NAME, VAL) (((PTR)->ADDR_NAME) = (VAL))
-#define pci_unmap_len(PTR, LEN_NAME) ((PTR)->LEN_NAME)
-#define pci_unmap_len_set(PTR, LEN_NAME, VAL) (((PTR)->LEN_NAME) = (VAL))
-#else
-#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME)
-#define DECLARE_PCI_UNMAP_LEN(LEN_NAME)
-#define pci_unmap_addr(PTR, ADDR_NAME) (0)
-#define pci_unmap_addr_set(PTR, ADDR_NAME, VAL) do { } while (0)
-#define pci_unmap_len(PTR, LEN_NAME) (0)
-#define pci_unmap_len_set(PTR, LEN_NAME, VAL) do { } while (0)
-#endif
+#define DECLARE_PCI_UNMAP_ADDR DECLARE_DMA_UNMAP_ADDR
+#define DECLARE_PCI_UNMAP_LEN DECLARE_DMA_UNMAP_LEN
+#define pci_unmap_addr dma_unmap_addr
+#define pci_unmap_addr_set dma_unmap_addr_set
+#define pci_unmap_len dma_unmap_len
+#define pci_unmap_len_set dma_unmap_len_set
#endif
--
1.5.6.5
On Fri, 12 Feb 2010 15:04:52 +0900
FUJITA Tomonori <[email protected]> wrote:
> Adds the following macros:
>
> DECLARE_DMA_UNMAP_ADDR(ADDR_NAME)
> DECLARE_DMA_UNMAP_LEN(LEN_NAME)
> dma_unmap_addr(PTR, ADDR_NAME)
> dma_unmap_addr_set(PTR, ADDR_NAME, VAL)
> dma_unmap_len(PTR, LEN_NAME)
> dma_unmap_len_set(PTR, LEN_NAME, VAL)
>
> The API corresponds to the pci_unmap state API. We'll move to this new
> generic API from the PCI specific API in the long term. As
> include/asm-generic/pci-dma-compat.h does, the pci_unmap API simply
> calls the new generic API for some time.
>
grumble.
>
> +#ifdef CONFIG_NEED_DMA_MAP_STATE
> +#define DECLARE_DMA_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME;
> +#define DECLARE_DMA_UNMAP_LEN(LEN_NAME) __u32 LEN_NAME;
Adding the semicolons is dopey.
(And these are "definitions", not "declarations" but I'm close to
giving up on that fight).
> +#define dma_unmap_addr(PTR, ADDR_NAME) ((PTR)->ADDR_NAME)
> +#define dma_unmap_addr_set(PTR, ADDR_NAME, VAL) (((PTR)->ADDR_NAME) = (VAL))
> +#define dma_unmap_len(PTR, LEN_NAME) ((PTR)->LEN_NAME)
> +#define dma_unmap_len_set(PTR, LEN_NAME, VAL) (((PTR)->LEN_NAME) = (VAL))
> +#else
> +#define DECLARE_DMA_MAP_ADDR(ADDR_NAME)
> +#define DECLARE_DMA_UNMAP_LEN(LEN_NAME)
> +#define dma_unmap_addr(PTR, ADDR_NAME) (0)
> +#define dma_unmap_addr_set(PTR, ADDR_NAME, VAL) do { } while (0)
> +#define dma_unmap_len(PTR, LEN_NAME) (0)
> +#define dma_unmap_len_set(PTR, LEN_NAME, VAL) do { } while (0)
> +#endif
> +
> #endif
> diff --git a/include/linux/pci-dma.h b/include/linux/pci-dma.h
> index cfd63ab..235a61e 100644
> --- a/include/linux/pci-dma.h
> +++ b/include/linux/pci-dma.h
> @@ -1,20 +1,11 @@
> #ifndef _LINUX_PCI_DMA_H
> #define _LINUX_PCI_DMA_H
>
> -#ifdef CONFIG_NEED_DMA_MAP_STATE
> -#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME;
> -#define DECLARE_PCI_UNMAP_LEN(LEN_NAME) __u32 LEN_NAME;
But we already screwed up the semicolon thing. If you grep the tree you'll
see that about half of the users of this macro added their own semicolon:
./drivers/net/cxgb3/sge.c: DECLARE_PCI_UNMAP_ADDR(addr);
./drivers/net/skge.h: DECLARE_PCI_UNMAP_ADDR(mapaddr);
./drivers/net/qla3xxx.h: DECLARE_PCI_UNMAP_ADDR(mapaddr);
./drivers/net/qla3xxx.h: DECLARE_PCI_UNMAP_ADDR(mapaddr);
./drivers/net/tg3.h: DECLARE_PCI_UNMAP_ADDR(mapping)
Perhaps someone will clean all that up sometime.
On Fri, 12 Feb 2010 11:51:57 -0800
Andrew Morton <[email protected]> wrote:
> > -#ifdef CONFIG_NEED_DMA_MAP_STATE
> > -#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME;
> > -#define DECLARE_PCI_UNMAP_LEN(LEN_NAME) __u32 LEN_NAME;
>
> But we already screwed up the semicolon thing. If you grep the tree you'll
> see that about half of the users of this macro added their own semicolon:
Yeah, I know. PCI-DMA-mapping.txt says:
NOTE: DO NOT put a semicolon at the end of the DECLARE_*() macro.
But there are some other DECLARE_ macros that don't have the
semicolons so users could be easily confused.
#define DEFINE_DMA_MAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME
looks better?
> ./drivers/net/cxgb3/sge.c: DECLARE_PCI_UNMAP_ADDR(addr);
> ./drivers/net/skge.h: DECLARE_PCI_UNMAP_ADDR(mapaddr);
> ./drivers/net/qla3xxx.h: DECLARE_PCI_UNMAP_ADDR(mapaddr);
> ./drivers/net/qla3xxx.h: DECLARE_PCI_UNMAP_ADDR(mapaddr);
> ./drivers/net/tg3.h: DECLARE_PCI_UNMAP_ADDR(mapping)
>
>
> Perhaps someone will clean all that up sometime.
I plan to replace these PCI API with the new generic API so I can take
care of them together.
On Sat, 13 Feb 2010 11:49:09 +0900 FUJITA Tomonori <[email protected]> wrote:
> On Fri, 12 Feb 2010 11:51:57 -0800
> Andrew Morton <[email protected]> wrote:
>
> > > -#ifdef CONFIG_NEED_DMA_MAP_STATE
> > > -#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME;
> > > -#define DECLARE_PCI_UNMAP_LEN(LEN_NAME) __u32 LEN_NAME;
> >
> > But we already screwed up the semicolon thing. If you grep the tree you'll
> > see that about half of the users of this macro added their own semicolon:
>
> Yeah, I know. PCI-DMA-mapping.txt says:
>
> NOTE: DO NOT put a semicolon at the end of the DECLARE_*() macro.
>
>
> But there are some other DECLARE_ macros that don't have the
> semicolons so users could be easily confused.
yup. Users already got confused.
> #define DEFINE_DMA_MAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME
>
> looks better?
yes. People expect to have to put the semicolon in there, so they do.
>
> > ./drivers/net/cxgb3/sge.c: DECLARE_PCI_UNMAP_ADDR(addr);
> > ./drivers/net/skge.h: DECLARE_PCI_UNMAP_ADDR(mapaddr);
> > ./drivers/net/qla3xxx.h: DECLARE_PCI_UNMAP_ADDR(mapaddr);
> > ./drivers/net/qla3xxx.h: DECLARE_PCI_UNMAP_ADDR(mapaddr);
> > ./drivers/net/tg3.h: DECLARE_PCI_UNMAP_ADDR(mapping)
> >
> >
> > Perhaps someone will clean all that up sometime.
>
> I plan to replace these PCI API with the new generic API so I can take
> care of them together.
cool.
On Fri, 12 Feb 2010 20:44:05 -0800
Andrew Morton <[email protected]> wrote:
> On Sat, 13 Feb 2010 11:49:09 +0900 FUJITA Tomonori <[email protected]> wrote:
>
> > On Fri, 12 Feb 2010 11:51:57 -0800
> > Andrew Morton <[email protected]> wrote:
> >
> > > > -#ifdef CONFIG_NEED_DMA_MAP_STATE
> > > > -#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME;
> > > > -#define DECLARE_PCI_UNMAP_LEN(LEN_NAME) __u32 LEN_NAME;
> > >
> > > But we already screwed up the semicolon thing. If you grep the tree you'll
> > > see that about half of the users of this macro added their own semicolon:
> >
> > Yeah, I know. PCI-DMA-mapping.txt says:
> >
> > NOTE: DO NOT put a semicolon at the end of the DECLARE_*() macro.
> >
> >
> > But there are some other DECLARE_ macros that don't have the
> > semicolons so users could be easily confused.
>
> yup. Users already got confused.
>
> > #define DEFINE_DMA_MAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME
> >
> > looks better?
>
> yes. People expect to have to put the semicolon in there, so they do.
Ok, how about this instead of the previous patch?
=
From: FUJITA Tomonori <[email protected]>
Subject: [PATCH -mm v2] dma-mapping.h: add the dma_unmap state API
Adds the following macros:
DEFINE_DMA_UNMAP_ADDR(ADDR_NAME)
DEFINE_DMA_UNMAP_LEN(LEN_NAME)
dma_unmap_addr(PTR, ADDR_NAME)
dma_unmap_addr_set(PTR, ADDR_NAME, VAL)
dma_unmap_len(PTR, LEN_NAME)
dma_unmap_len_set(PTR, LEN_NAME, VAL)
The API corresponds to the pci_unmap state API. We'll move to this new
generic API from the PCI specific API in the long term. As
include/asm-generic/pci-dma-compat.h does, the pci_unmap API simply
calls the new generic API for some time.
Note that DEFINE_DMA_UNMAP_ADDR and DEFINE_DMA_UNMAP_LEN are slightly
different from DECLARE_PCI_UNMAP_ADDR and
DECLARE_PCI_UNMAP_LEN. Unlike DECLARE_PCI_UNMAP_ADDR and
DECLARE_PCI_UNMAP_LEN, DEFINE_DMA_UNMAP_ADDR and DEFINE_DMA_UNMAP_LEN
need a semicolon at the end of the macros. It looks more
straightforward.
Signed-off-by: FUJITA Tomonori <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Jesse Barnes <[email protected]>
Cc: Arnd Bergmann <[email protected]>
---
Documentation/DMA-API.txt | 58 +++++++++++++++++++++++++++++++++++++++++++
include/linux/dma-mapping.h | 16 ++++++++++++
include/linux/pci-dma.h | 21 ++++-----------
3 files changed, 80 insertions(+), 15 deletions(-)
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index db20b37..0fc5728 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -482,6 +482,64 @@ void whizco_dma_map_sg_attrs(struct device *dev, dma_addr_t dma_addr,
....
+Part Ie - Optimizing Unmap State Space Consumption
+--------------------------------
+
+On some platforms, dma_unmap_{single,page}() is simply a nop.
+Therefore, keeping track of the mapping address and length is a waste
+of space. Instead of filling your drivers up with ifdefs and the like
+to "work around" this (which would defeat the whole purpose of a
+portable API) the following facilities are provided.
+
+Actually, instead of describing the macros one by one, we'll
+transform some example code.
+
+1) Use DEFINE_DMA_UNMAP_{ADDR,LEN} in state saving structures.
+ Example, before:
+
+ struct ring_state {
+ struct sk_buff *skb;
+ dma_addr_t mapping;
+ __u32 len;
+ };
+
+ after:
+
+ struct ring_state {
+ struct sk_buff *skb;
+ DEFINE_DMA_UNMAP_ADDR(mapping);
+ DEFINE_DMA_UNMAP_LEN(len);
+ };
+
+2) Use dma_unmap_{addr,len}_set to set these values.
+ Example, before:
+
+ ringp->mapping = FOO;
+ ringp->len = BAR;
+
+ after:
+
+ dma_unmap_addr_set(ringp, mapping, FOO);
+ dma_unmap_len_set(ringp, len, BAR);
+
+3) Use dma_unmap_{addr,len} to access these values.
+ Example, before:
+
+ dma_unmap_single(dev, ringp->mapping, ringp->len,
+ DMA_FROM_DEVICE);
+
+ after:
+
+ dma_unmap_single(dev,
+ dma_unmap_addr(ringp, mapping),
+ dma_unmap_len(ringp, len),
+ DMA_FROM_DEVICE);
+
+It really should be self-explanatory. We treat the ADDR and LEN
+separately, because it is possible for an implementation to only
+need the address in order to perform the unmap operation.
+
+
Part II - Advanced dma_ usage
-----------------------------
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 8357721..e00c5c9 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -240,4 +240,20 @@ struct dma_attrs;
#endif /* CONFIG_HAVE_DMA_ATTRS */
+#ifdef CONFIG_NEED_DMA_MAP_STATE
+#define DEFINE_DMA_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME
+#define DEFINE_DMA_UNMAP_LEN(LEN_NAME) __u32 LEN_NAME
+#define dma_unmap_addr(PTR, ADDR_NAME) ((PTR)->ADDR_NAME)
+#define dma_unmap_addr_set(PTR, ADDR_NAME, VAL) (((PTR)->ADDR_NAME) = (VAL))
+#define dma_unmap_len(PTR, LEN_NAME) ((PTR)->LEN_NAME)
+#define dma_unmap_len_set(PTR, LEN_NAME, VAL) (((PTR)->LEN_NAME) = (VAL))
+#else
+#define DEFINE_DMA_MAP_ADDR(ADDR_NAME)
+#define DEFINE_DMA_UNMAP_LEN(LEN_NAME)
+#define dma_unmap_addr(PTR, ADDR_NAME) (0)
+#define dma_unmap_addr_set(PTR, ADDR_NAME, VAL) do { } while (0)
+#define dma_unmap_len(PTR, LEN_NAME) (0)
+#define dma_unmap_len_set(PTR, LEN_NAME, VAL) do { } while (0)
+#endif
+
#endif
diff --git a/include/linux/pci-dma.h b/include/linux/pci-dma.h
index cfd63ab..549a041 100644
--- a/include/linux/pci-dma.h
+++ b/include/linux/pci-dma.h
@@ -1,20 +1,11 @@
#ifndef _LINUX_PCI_DMA_H
#define _LINUX_PCI_DMA_H
-#ifdef CONFIG_NEED_DMA_MAP_STATE
-#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME;
-#define DECLARE_PCI_UNMAP_LEN(LEN_NAME) __u32 LEN_NAME;
-#define pci_unmap_addr(PTR, ADDR_NAME) ((PTR)->ADDR_NAME)
-#define pci_unmap_addr_set(PTR, ADDR_NAME, VAL) (((PTR)->ADDR_NAME) = (VAL))
-#define pci_unmap_len(PTR, LEN_NAME) ((PTR)->LEN_NAME)
-#define pci_unmap_len_set(PTR, LEN_NAME, VAL) (((PTR)->LEN_NAME) = (VAL))
-#else
-#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME)
-#define DECLARE_PCI_UNMAP_LEN(LEN_NAME)
-#define pci_unmap_addr(PTR, ADDR_NAME) (0)
-#define pci_unmap_addr_set(PTR, ADDR_NAME, VAL) do { } while (0)
-#define pci_unmap_len(PTR, LEN_NAME) (0)
-#define pci_unmap_len_set(PTR, LEN_NAME, VAL) do { } while (0)
-#endif
+#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME) DEFINE_DMA_UNMAP_ADDR(ADDR_NAME);
+#define DECLARE_PCI_UNMAP_LEN(LEN_NAME) DEFINE_DMA_UNMAP_LEN(LEN_NAME);
+#define pci_unmap_addr dma_unmap_addr
+#define pci_unmap_addr_set dma_unmap_addr_set
+#define pci_unmap_len dma_unmap_len
+#define pci_unmap_len_set dma_unmap_len_set
#endif
--
1.5.6.5