The target core runs into a warning in the linux/sbitmap.h
file in some configurations:
In file included from include/target/target_core_base.h:7,
from drivers/target/target_core_fabric_lib.c:41:
include/linux/sbitmap.h:331:46: error: 'struct seq_file' declared inside parameter list will not be visible outside of this definition or declaration [-Werror]
void sbitmap_show(struct sbitmap *sb, struct seq_file *m);
^~~~~~~~
In general, headers should not depend on others being included first,
so this fixes it with a forward declaration for that struct name, but
we probably want to merge the patch through the scsi tree to help
bisection.
Fixes: 10e9cbb6b531 ("scsi: target: Convert target drivers to use sbitmap")
Signed-off-by: Arnd Bergmann <[email protected]>
---
include/linux/sbitmap.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h
index e6539536dea9..cc54b9f7ff8b 100644
--- a/include/linux/sbitmap.h
+++ b/include/linux/sbitmap.h
@@ -321,6 +321,8 @@ static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr)
unsigned int sbitmap_weight(const struct sbitmap *sb);
+struct seq_file;
+
/**
* sbitmap_show() - Dump &struct sbitmap information to a &struct seq_file.
* @sb: Bitmap to show.
--
2.9.0
On Fri, 2018-07-06 at 15:23 +0200, Arnd Bergmann wrote:
> The target core runs into a warning in the linux/sbitmap.h
> file in some configurations:
>
> In file included from include/target/target_core_base.h:7,
> from drivers/target/target_core_fabric_lib.c:41:
> include/linux/sbitmap.h:331:46: error: 'struct seq_file' declared inside parameter list will not be visible outside of this definition or declaration [-Werror]
> void sbitmap_show(struct sbitmap *sb, struct seq_file *m);
> ^~~~~~~~
>
> In general, headers should not depend on others being included first,
> so this fixes it with a forward declaration for that struct name, but
> we probably want to merge the patch through the scsi tree to help
> bisection.
>
> Fixes: 10e9cbb6b531 ("scsi: target: Convert target drivers to use sbitmap")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> include/linux/sbitmap.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h
> index e6539536dea9..cc54b9f7ff8b 100644
> --- a/include/linux/sbitmap.h
> +++ b/include/linux/sbitmap.h
> @@ -321,6 +321,8 @@ static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr)
>
> unsigned int sbitmap_weight(const struct sbitmap *sb);
>
> +struct seq_file;
> +
> /**
> * sbitmap_show() - Dump &struct sbitmap information to a &struct seq_file.
> * @sb: Bitmap to show.
In many Linux kernel header files all forward declarations are grouped near
the start of the header file (after #includes and #defines and before structure
definitions). Should we follow that pattern in <linux/sbitmap.h>?
Thanks,
Bart.
On Fri, Jul 6, 2018 at 7:07 PM, Bart Van Assche <[email protected]> wrote:
> On Fri, 2018-07-06 at 15:23 +0200, Arnd Bergmann wrote:
>> The target core runs into a warning in the linux/sbitmap.h
>> file in some configurations:
>>
>> In file included from include/target/target_core_base.h:7,
>> from drivers/target/target_core_fabric_lib.c:41:
>> include/linux/sbitmap.h:331:46: error: 'struct seq_file' declared inside parameter list will not be visible outside of this definition or declaration [-Werror]
>> void sbitmap_show(struct sbitmap *sb, struct seq_file *m);
>> ^~~~~~~~
>>
>> In general, headers should not depend on others being included first,
>> so this fixes it with a forward declaration for that struct name, but
>> we probably want to merge the patch through the scsi tree to help
>> bisection.
>>
>> Fixes: 10e9cbb6b531 ("scsi: target: Convert target drivers to use sbitmap")
>> Signed-off-by: Arnd Bergmann <[email protected]>
>> ---
>> include/linux/sbitmap.h | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h
>> index e6539536dea9..cc54b9f7ff8b 100644
>> --- a/include/linux/sbitmap.h
>> +++ b/include/linux/sbitmap.h
>> @@ -321,6 +321,8 @@ static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr)
>>
>> unsigned int sbitmap_weight(const struct sbitmap *sb);
>>
>> +struct seq_file;
>> +
>> /**
>> * sbitmap_show() - Dump &struct sbitmap information to a &struct seq_file.
>> * @sb: Bitmap to show.
>
> In many Linux kernel header files all forward declarations are grouped near
> the start of the header file (after #includes and #defines and before structure
> definitions). Should we follow that pattern in <linux/sbitmap.h>?
I couldn't find any other such declaration in this header, so I just put it
close to where it's first used, which is the other common way to do it.
I checked all of include/linux and found that you are right, a clear
majority of the headers just pull all struct declarations in the front.
Arnd