Subject: [PATCH] arm64: Add ARCH_HAS_SG_CHAIN

From: [email-masked] (Will Deacon)
Date: Fri, 14 Mar 2014 10:05:45 +0000

Hi Laura,

On Fri, Mar 14, 2014 at 12:50:41AM +0000, Laura Abbott wrote:
> On 3/13/2014 11:01 AM, Will Deacon wrote:
> > On Thu, Mar 13, 2014 at 05:49:23PM +0000, Laura Abbott wrote:
> >> It's useful to be able to chain scatterlists together for very large
> >> scatter allocations. Define ARCH_HAS_SG_CHAIN to let this happen.
> >>
> >> Signed-off-by: Laura Abbott <[email-masked]>
> >> ---
> >>   arch/arm64/include/asm/scatterlist.h | 21 +++++++++++++++++++++
> >>   1 file changed, 21 insertions(+)
> >>   create mode 100644 arch/arm64/include/asm/scatterlist.h

[...]

> >> +#ifndef __ASM_SCATTERLIST_H
> >> +#define __ASM_SCATTERLIST_H
> >> +
> >> +#include <asm-generic/scatterlist.h>
> >> +
> >> +#define ARCH_HAS_SG_CHAIN
> >
> > Hmm, I wonder if this should be a Kconfig option instead, to avoid the need
> > for the dummy header?
> >
> > Will
> >
> 
> Yeah, it does seem non-standard at this point. Something like the
> following perhaps?

Yes, that looks like the right sort of thing, thanks.

  Acked-by: Will Deacon <[email-masked]>

Probably easiest to merge via akpm if you can get some more acks.

Will

> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 1594945..8122294 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -82,6 +82,7 @@ config ARM
>   	  <http://www.arm.linux.org.uk/>.
> 
>   config ARM_HAS_SG_CHAIN
> +	select ARCH_HAS_SG_CHAIN
>   	bool
> 
>   config NEED_SG_DMA_LENGTH
> diff --git a/arch/arm/include/asm/scatterlist.h 
> b/arch/arm/include/asm/scatterlist.h
> index cefdb8f..2f87870 100644
> --- a/arch/arm/include/asm/scatterlist.h
> +++ b/arch/arm/include/asm/scatterlist.h
> @@ -1,10 +1,6 @@
>   #ifndef _ASMARM_SCATTERLIST_H
>   #define _ASMARM_SCATTERLIST_H
> 
> -#ifdef CONFIG_ARM_HAS_SG_CHAIN
> -#define ARCH_HAS_SG_CHAIN
> -#endif
> -
>   #include <asm/memory.h>
>   #include <asm/types.h>
>   #include <asm-generic/scatterlist.h>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 27bbcfc..f2f95f4 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -2,6 +2,7 @@ config ARM64
>   	def_bool y
>   	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
>   	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_HAS_SG_CHAIN
>   	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
>   	select ARCH_WANT_OPTIONAL_GPIOLIB
>   	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
> diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
> index 0c8e553..13e2e8b 100644
> --- a/arch/ia64/Kconfig
> +++ b/arch/ia64/Kconfig
> @@ -44,6 +44,7 @@ config IA64
>   	select HAVE_MOD_ARCH_SPECIFIC
>   	select MODULES_USE_ELF_RELA
>   	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_HAS_SG_CHAIN
>   	default y
>   	help
>   	  The Itanium Processor Family is Intel's 64-bit successor to
> diff --git a/arch/ia64/include/asm/scatterlist.h 
> b/arch/ia64/include/asm/scatterlist.h
> index 08fd93b..c19b59d 100644
> --- a/arch/ia64/include/asm/scatterlist.h
> +++ b/arch/ia64/include/asm/scatterlist.h
> @@ -2,6 +2,5 @@
>   #define _ASM_IA64_SCATTERLIST_H
> 
>   #include <asm-generic/scatterlist.h>
> -#define ARCH_HAS_SG_CHAIN
> 
>   #endif /* _ASM_IA64_SCATTERLIST_H */
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 957bf34..659aee2 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -141,6 +141,7 @@ config PPC
>   	select HAVE_DEBUG_STACKOVERFLOW
>   	select HAVE_IRQ_EXIT_ON_IRQ_STACK
>   	select ARCH_USE_CMPXCHG_LOCKREF if PPC64
> +	select ARCH_HAS_SG_CHAIN
> 
>   config GENERIC_CSUM
>   	def_bool CPU_LITTLE_ENDIAN
> diff --git a/arch/powerpc/include/asm/scatterlist.h 
> b/arch/powerpc/include/asm/scatterlist.h
> index de1f620..1f51af5 100644
> --- a/arch/powerpc/include/asm/scatterlist.h
> +++ b/arch/powerpc/include/asm/scatterlist.h
> @@ -12,6 +12,4 @@
>   #include <asm/dma.h>
>   #include <asm-generic/scatterlist.h>
> 
> -#define ARCH_HAS_SG_CHAIN
> -
>   #endif /* _ASM_POWERPC_SCATTERLIST_H */
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index 65a0775..d6c2059 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -142,6 +142,7 @@ config S390
>   	select SYSCTL_EXCEPTION_TRACE
>   	select VIRT_CPU_ACCOUNTING
>   	select VIRT_TO_BUS
> +	select ARCH_HAS_SG_CHAIN
> 
>   config SCHED_OMIT_FRAME_POINTER
>   	def_bool y
> diff --git a/arch/s390/include/asm/scatterlist.h 
> b/arch/s390/include/asm/scatterlist.h
> index 6d45ef6..4aaea56 100644
> --- a/arch/s390/include/asm/scatterlist.h
> +++ b/arch/s390/include/asm/scatterlist.h
> @@ -1,3 +1,2 @@
>   #include <asm-generic/scatterlist.h>
> 
> -#define ARCH_HAS_SG_CHAIN
> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
> index 7d8b7e9..7a179fe 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -42,6 +42,7 @@ config SPARC
>   	select MODULES_USE_ELF_RELA
>   	select ODD_RT_SIGACTION
>   	select OLD_SIGSUSPEND
> +	select ARCH_HAS_SG_CHAIN
> 
>   config SPARC32
>   	def_bool !64BIT
> diff --git a/arch/sparc/include/asm/scatterlist.h 
> b/arch/sparc/include/asm/scatterlist.h
> index 92bb638..6eab378 100644
> --- a/arch/sparc/include/asm/scatterlist.h
> +++ b/arch/sparc/include/asm/scatterlist.h
> @@ -3,6 +3,4 @@
> 
>   #include <asm-generic/scatterlist.h>
> 
> -#define ARCH_HAS_SG_CHAIN
> -
>   #endif /* !(_SPARC_SCATTERLIST_H) */
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 0af5250..76997dc 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -127,6 +127,7 @@ config X86
>   	select HAVE_DEBUG_STACKOVERFLOW
>   	select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
>   	select HAVE_CC_STACKPROTECTOR
> +	select ARCH_HAS_SG_CHAIN
> 
>   config INSTRUCTION_DECODER
>   	def_bool y
> diff --git a/arch/x86/include/asm/scatterlist.h 
> b/arch/x86/include/asm/scatterlist.h
> index 4240878..b08f91d 100644
> --- a/arch/x86/include/asm/scatterlist.h
> +++ b/arch/x86/include/asm/scatterlist.h
> @@ -3,6 +3,4 @@
> 
>   #include <asm-generic/scatterlist.h>
> 
> -#define ARCH_HAS_SG_CHAIN
> -
>   #endif /* _ASM_X86_SCATTERLIST_H */
> diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
> index a964f72..4b152c8 100644
> --- a/include/linux/scatterlist.h
> +++ b/include/linux/scatterlist.h
> @@ -136,7 +136,7 @@ static inline void sg_set_buf(struct scatterlist 
> *sg, const void *buf,
>   static inline void sg_chain(struct scatterlist *prv, unsigned int 
> prv_nents,
>   			    struct scatterlist *sgl)
>   {
> -#ifndef ARCH_HAS_SG_CHAIN
> +#ifndef CONFIG_ARCH_HAS_SG_CHAIN
>   	BUG();
>   #endif
> 
> diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
> index 0a4edfe..d34cf2d 100644
> --- a/include/scsi/scsi.h
> +++ b/include/scsi/scsi.h
> @@ -31,7 +31,7 @@ enum scsi_timeouts {
>    * Like SCSI_MAX_SG_SEGMENTS, but for archs that have sg chaining. 
> This limit
>    * is totally arbitrary, a setting of 2048 will get you at least 8mb ios.
>    */
> -#ifdef ARCH_HAS_SG_CHAIN
> +#ifdef CONFIG_ARCH_HAS_SG_CHAIN
>   #define SCSI_MAX_SG_CHAIN_SEGMENTS	2048
>   #else
>   #define SCSI_MAX_SG_CHAIN_SEGMENTS	SCSI_MAX_SG_SEGMENTS
> diff --git a/lib/Kconfig b/lib/Kconfig
> index 991c98b..32c68d3 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -451,4 +451,11 @@ config UCS2_STRING
> 
>   source "lib/fonts/Kconfig"
> 
> +#
> +# sg chaining option
> +#
> +
> +config ARCH_HAS_SG_CHAIN
> +	def_bool n
> +
>   endmenu
> diff --git a/lib/scatterlist.c b/lib/scatterlist.c
> index 3a8e8e8..4251cbd 100644
> --- a/lib/scatterlist.c
> +++ b/lib/scatterlist.c
> @@ -73,7 +73,7 @@ EXPORT_SYMBOL(sg_nents);
>    **/
>   struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents)
>   {
> -#ifndef ARCH_HAS_SG_CHAIN
> +#ifndef CONFIG_ARCH_HAS_SG_CHAIN
>   	struct scatterlist *ret = &sgl[nents - 1];
>   #else
>   	struct scatterlist *sg, *ret = NULL;
> @@ -251,7 +251,7 @@ int __sg_alloc_table(struct sg_table *table, 
> unsigned int nents,
> 
>   	if (nents == 0)
>   		return -EINVAL;
> -#ifndef ARCH_HAS_SG_CHAIN
> +#ifndef CONFIG_ARCH_HAS_SG_CHAIN
>   	if (WARN_ON_ONCE(nents > max_ents))
>   		return -EINVAL;
>   #endif
> 
> -- 
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