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* [PATCH v2] bitfield.h: add FIELD_MAX() and field_max()
@ 2020-03-06  4:23 Alex Elder
  2020-03-10 21:29 ` Nathan Chancellor
  0 siblings, 1 reply; 5+ messages in thread
From: Alex Elder @ 2020-03-06  4:23 UTC (permalink / raw)
  To: David Miller, Jakub Kicinski, Al Viro
  Cc: Johannes Berg, Arnd Bergmann, Masahiro Yamada, Bjorn Andersson, lkml

Define FIELD_MAX(), which supplies the maximum value that can be
represented by a bitfield.  Define field_max() as well, to go
along with the lower-case forms of the field mask functions.

Signed-off-by: Alex Elder <elder@linaro.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
---
v2: Added Acked-by from Jakub.

David, I added you to this because it's probably easiest to take
this change in through your tree with the rest of the IPA code
(which uses field_max(), defined here).

					-Alex

 include/linux/bitfield.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index 4bbb5f1c8b5b..48ea093ff04c 100644
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -55,6 +55,19 @@
 					      (1ULL << __bf_shf(_mask))); \
 	})
 
+/**
+ * FIELD_MAX() - produce the maximum value representable by a field
+ * @_mask: shifted mask defining the field's length and position
+ *
+ * FIELD_MAX() returns the maximum value that can be held in the field
+ * specified by @_mask.
+ */
+#define FIELD_MAX(_mask)						\
+	({								\
+		__BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_MAX: ");	\
+		(typeof(_mask))((_mask) >> __bf_shf(_mask));		\
+	})
+
 /**
  * FIELD_FIT() - check if value fits in the field
  * @_mask: shifted mask defining the field's length and position
@@ -110,6 +123,7 @@ static __always_inline u64 field_mask(u64 field)
 {
 	return field / field_multiplier(field);
 }
+#define field_max(field)	((typeof(field))field_mask(field))
 #define ____MAKE_OP(type,base,to,from)					\
 static __always_inline __##type type##_encode_bits(base v, base field)	\
 {									\
-- 
2.20.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] bitfield.h: add FIELD_MAX() and field_max()
  2020-03-06  4:23 [PATCH v2] bitfield.h: add FIELD_MAX() and field_max() Alex Elder
@ 2020-03-10 21:29 ` Nathan Chancellor
  2020-03-10 21:58   ` Jakub Kicinski
  0 siblings, 1 reply; 5+ messages in thread
From: Nathan Chancellor @ 2020-03-10 21:29 UTC (permalink / raw)
  To: Alex Elder
  Cc: David Miller, Jakub Kicinski, Al Viro, Johannes Berg,
	Arnd Bergmann, Masahiro Yamada, Bjorn Andersson, lkml

On Thu, Mar 05, 2020 at 10:23:02PM -0600, Alex Elder wrote:
> Define FIELD_MAX(), which supplies the maximum value that can be
> represented by a bitfield.  Define field_max() as well, to go
> along with the lower-case forms of the field mask functions.
> 
> Signed-off-by: Alex Elder <elder@linaro.org>
> Acked-by: Jakub Kicinski <kuba@kernel.org>
> ---
> v2: Added Acked-by from Jakub.
> 
> David, I added you to this because it's probably easiest to take
> this change in through your tree with the rest of the IPA code
> (which uses field_max(), defined here).
> 
> 					-Alex
> 
>  include/linux/bitfield.h | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
> index 4bbb5f1c8b5b..48ea093ff04c 100644
> --- a/include/linux/bitfield.h
> +++ b/include/linux/bitfield.h
> @@ -55,6 +55,19 @@
>  					      (1ULL << __bf_shf(_mask))); \
>  	})
>  
> +/**
> + * FIELD_MAX() - produce the maximum value representable by a field
> + * @_mask: shifted mask defining the field's length and position
> + *
> + * FIELD_MAX() returns the maximum value that can be held in the field
> + * specified by @_mask.
> + */
> +#define FIELD_MAX(_mask)						\
> +	({								\
> +		__BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_MAX: ");	\
> +		(typeof(_mask))((_mask) >> __bf_shf(_mask));		\
> +	})
> +
>  /**
>   * FIELD_FIT() - check if value fits in the field
>   * @_mask: shifted mask defining the field's length and position
> @@ -110,6 +123,7 @@ static __always_inline u64 field_mask(u64 field)
>  {
>  	return field / field_multiplier(field);
>  }
> +#define field_max(field)	((typeof(field))field_mask(field))
>  #define ____MAKE_OP(type,base,to,from)					\
>  static __always_inline __##type type##_encode_bits(base v, base field)	\
>  {									\
> -- 
> 2.20.1
> 

Without this patch, the IPA driver that was picked up a couple of days
ago does not build...

$ make -j$(nproc) -s ARCH=arm64 CC=clang CROSS_COMPILE=aarch64-linux-gnu- O=out.arm32 distclean allyesconfig drivers/net/ipa/
../drivers/net/ipa/ipa_cmd.c:182:28: error: implicit declaration of function 'field_max' [-Werror,-Wimplicit-function-declaration]
        BUILD_BUG_ON(TABLE_SIZE > field_max(IP_FLTRT_FLAGS_HASH_SIZE_FMASK));
                                  ^
../drivers/net/ipa/ipa_cmd.c:182:28: note: did you mean 'field_mask'?
../include/linux/bitfield.h:109:28: note: 'field_mask' declared here
static __always_inline u64 field_mask(u64 field)
                           ^
../drivers/net/ipa/ipa_cmd.c:183:28: error: implicit declaration of function 'field_max' [-Werror,-Wimplicit-function-declaration]
        BUILD_BUG_ON(TABLE_SIZE > field_max(IP_FLTRT_FLAGS_NHASH_SIZE_FMASK));
                                  ^
../drivers/net/ipa/gsi.c:220:39: error: implicit declaration of function 'field_max' [-Werror,-Wimplicit-function-declaration]
        BUILD_BUG_ON(GSI_RING_ELEMENT_SIZE > field_max(ELEMENT_SIZE_FMASK));
                                             ^
2 errors generated.
../drivers/net/ipa/gsi.c:220:39: note: did you mean 'field_mask'?
../include/linux/bitfield.h:109:28: note: 'field_mask' declared here
static __always_inline u64 field_mask(u64 field)
                           ^
../drivers/net/ipa/gsi.c:223:39: error: implicit declaration of function 'field_max' [-Werror,-Wimplicit-function-declaration]
        BUILD_BUG_ON(GSI_RING_ELEMENT_SIZE > field_max(EV_ELEMENT_SIZE_FMASK));
                                             ^
make[5]: *** [../scripts/Makefile.build:267: drivers/net/ipa/ipa_cmd.o] Error 1
make[5]: *** Waiting for unfinished jobs....
../drivers/net/ipa/gsi.c:710:16: error: implicit declaration of function 'field_max' [-Werror,-Wimplicit-function-declaration]
                wrr_weight = field_max(WRR_WEIGHT_FMASK);
                             ^
3 errors generated.
make[5]: *** [../scripts/Makefile.build:267: drivers/net/ipa/gsi.o] Error 1
../drivers/net/ipa/ipa_endpoint.c:584:14: error: implicit declaration of function 'field_max' [-Werror,-Wimplicit-function-declaration]
        if (scale > field_max(SCALE_FMASK))
                    ^
../drivers/net/ipa/ipa_endpoint.c:584:14: note: did you mean 'field_mask'?
../include/linux/bitfield.h:109:28: note: 'field_mask' declared here
static __always_inline u64 field_mask(u64 field)
                           ^
../drivers/net/ipa/ipa_endpoint.c:965:16: error: implicit declaration of function 'field_max' [-Werror,-Wimplicit-function-declaration]
        return val == field_max(IPA_STATUS_FLAGS1_RT_RULE_ID_FMASK);
                      ^
2 errors generated.

This probably should go through the net-next tree to avoid that build
breakage.

Cheers,
Nathan

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] bitfield.h: add FIELD_MAX() and field_max()
  2020-03-10 21:29 ` Nathan Chancellor
@ 2020-03-10 21:58   ` Jakub Kicinski
  2020-03-11  1:48     ` Alex Elder
  0 siblings, 1 reply; 5+ messages in thread
From: Jakub Kicinski @ 2020-03-10 21:58 UTC (permalink / raw)
  To: Nathan Chancellor
  Cc: Alex Elder, David Miller, Al Viro, Johannes Berg, Arnd Bergmann,
	Masahiro Yamada, Bjorn Andersson, lkml

On Tue, 10 Mar 2020 14:29:38 -0700 Nathan Chancellor wrote:
> Without this patch, the IPA driver that was picked up a couple of days
> ago does not build...

😳 

Yes please, Alex could you repost ASAP with [PATCH net-next] subject
and CC netdev to get it into the netdev patchwork?

Please also make IPA:

	depends on (ARCH_QCOM || COMPILE_TEST) && 64BIT && NET

Otherwise it's really hard to make sure the code builds.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] bitfield.h: add FIELD_MAX() and field_max()
  2020-03-10 21:58   ` Jakub Kicinski
@ 2020-03-11  1:48     ` Alex Elder
  2020-03-11  2:45       ` Alex Elder
  0 siblings, 1 reply; 5+ messages in thread
From: Alex Elder @ 2020-03-11  1:48 UTC (permalink / raw)
  To: Jakub Kicinski, Nathan Chancellor
  Cc: David Miller, Al Viro, Johannes Berg, Arnd Bergmann,
	Masahiro Yamada, Bjorn Andersson, lkml

On 3/10/20 4:58 PM, Jakub Kicinski wrote:
> On Tue, 10 Mar 2020 14:29:38 -0700 Nathan Chancellor wrote:
>> Without this patch, the IPA driver that was picked up a couple of days
>> ago does not build...
> 
> 😳 
> 
> Yes please, Alex could you repost ASAP with [PATCH net-next] subject
> and CC netdev to get it into the netdev patchwork?
> 
> Please also make IPA:
> 
> 	depends on (ARCH_QCOM || COMPILE_TEST) && 64BIT && NET
> 
> Otherwise it's really hard to make sure the code builds.

Sorry all.  I have been on vacation the last few days and only now
saw this.

I will put this together shortly.

					-Alex


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] bitfield.h: add FIELD_MAX() and field_max()
  2020-03-11  1:48     ` Alex Elder
@ 2020-03-11  2:45       ` Alex Elder
  0 siblings, 0 replies; 5+ messages in thread
From: Alex Elder @ 2020-03-11  2:45 UTC (permalink / raw)
  To: Jakub Kicinski, Nathan Chancellor
  Cc: David Miller, Al Viro, Johannes Berg, Arnd Bergmann,
	Masahiro Yamada, Bjorn Andersson, lkml

On 3/10/20 8:48 PM, Alex Elder wrote:
> On 3/10/20 4:58 PM, Jakub Kicinski wrote:
>> On Tue, 10 Mar 2020 14:29:38 -0700 Nathan Chancellor wrote:
>>> Without this patch, the IPA driver that was picked up a couple of days
>>> ago does not build...
>>
>> 😳 
>>
>> Yes please, Alex could you repost ASAP with [PATCH net-next] subject
>> and CC netdev to get it into the netdev patchwork?
>>
>> Please also make IPA:
>>
>> 	depends on (ARCH_QCOM || COMPILE_TEST) && 64BIT && NET
>>
>> Otherwise it's really hard to make sure the code builds.
> 
> Sorry all.  I have been on vacation the last few days and only now
> saw this.
> 
> I will put this together shortly.

I just sent an updated version of the field_max() patch.  I will do
the COMPILE_TEST change separately (and not today).

					-Alex

> 					-Alex
> 


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-03-11  2:45 UTC | newest]

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2020-03-06  4:23 [PATCH v2] bitfield.h: add FIELD_MAX() and field_max() Alex Elder
2020-03-10 21:29 ` Nathan Chancellor
2020-03-10 21:58   ` Jakub Kicinski
2020-03-11  1:48     ` Alex Elder
2020-03-11  2:45       ` Alex Elder

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