The whole header file deals with swap entries and PTEs, none of which
can exist for nommu builds.
Signed-off-by: Christoph Hellwig <[email protected]>
---
include/linux/swapops.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index 4d961668e5fc..b02922556846 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -6,6 +6,8 @@
#include <linux/bug.h>
#include <linux/mm_types.h>
+#ifdef CONFIG_MMU
+
/*
* swapcache pages are stored in the swapper_space radix tree. We want to
* get good packing density in that tree, so the index should be dense in
@@ -50,13 +52,11 @@ static inline pgoff_t swp_offset(swp_entry_t entry)
return entry.val & SWP_OFFSET_MASK;
}
-#ifdef CONFIG_MMU
/* check whether a pte points to a swap entry */
static inline int is_swap_pte(pte_t pte)
{
return !pte_none(pte) && !pte_present(pte);
}
-#endif
/*
* Convert the arch-dependent pte representation of a swp_entry_t into an
@@ -375,4 +375,5 @@ static inline int non_swap_entry(swp_entry_t entry)
}
#endif
+#endif /* CONFIG_MMU */
#endif /* _LINUX_SWAPOPS_H */
--
2.20.1
On 6/10/19 11:16 PM, Christoph Hellwig wrote:
> The whole header file deals with swap entries and PTEs, none of which
> can exist for nommu builds.
Although I agree with the patch, I'm wondering how you get into it?
Cheers
Vladimir
>
> Signed-off-by: Christoph Hellwig <[email protected]>
> ---
> include/linux/swapops.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/swapops.h b/include/linux/swapops.h
> index 4d961668e5fc..b02922556846 100644
> --- a/include/linux/swapops.h
> +++ b/include/linux/swapops.h
> @@ -6,6 +6,8 @@
> #include <linux/bug.h>
> #include <linux/mm_types.h>
>
> +#ifdef CONFIG_MMU
> +
> /*
> * swapcache pages are stored in the swapper_space radix tree. We want to
> * get good packing density in that tree, so the index should be dense in
> @@ -50,13 +52,11 @@ static inline pgoff_t swp_offset(swp_entry_t entry)
> return entry.val & SWP_OFFSET_MASK;
> }
>
> -#ifdef CONFIG_MMU
> /* check whether a pte points to a swap entry */
> static inline int is_swap_pte(pte_t pte)
> {
> return !pte_none(pte) && !pte_present(pte);
> }
> -#endif
>
> /*
> * Convert the arch-dependent pte representation of a swp_entry_t into an
> @@ -375,4 +375,5 @@ static inline int non_swap_entry(swp_entry_t entry)
> }
> #endif
>
> +#endif /* CONFIG_MMU */
> #endif /* _LINUX_SWAPOPS_H */
>
On Tue, Jun 11, 2019 at 11:15:44AM +0100, Vladimir Murzin wrote:
> On 6/10/19 11:16 PM, Christoph Hellwig wrote:
> > The whole header file deals with swap entries and PTEs, none of which
> > can exist for nommu builds.
>
> Although I agree with the patch, I'm wondering how you get into it?
Without that the RISC-V nommu blows up like this:
In file included from mm/vmscan.c:58:
./include/linux/swapops.h: In function ‘pte_to_swp_entry’:
./include/linux/swapops.h:71:15: error: implicit declaration of function ‘__pte_to_swp_entry’; did you mean ‘pte_to_swp_entry’? [-Werror=implicit-function-declaration]
arch_entry = __pte_to_swp_entry(pte);
^~~~~~~~~~~~~~~~~~
pte_to_swp_entry
./include/linux/swapops.h:71:13: error: incompatible types when assigning to type ‘swp_entry_t’ {aka ‘struct <anonymous>’} from type ‘int’
arch_entry = __pte_to_swp_entry(pte);
^
./include/linux/swapops.h:72:19: error: implicit declaration of function ‘__swp_type’; did you mean ‘swp_type’? [-Werror=implicit-function-declaration]
return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
^~~~~~~~~~
swp_type
./include/linux/swapops.h:72:43: error: implicit declaration of function ‘__swp_offset’; did you mean ‘swp_offset’? [-Werror=implicit-function-declaration]
return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
^~~~~~~~~~~~
swp_offset
./include/linux/swapops.h: In function ‘swp_entry_to_pte’:
./include/linux/swapops.h:83:15: error: implicit declaration of function ‘__swp_entry’; did you mean ‘swp_entry’? [-Werror=implicit-function-declaration]
arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
^~~~~~~~~~~
swp_entry
./include/linux/swapops.h:83:13: error: incompatible types when assigning to type ‘swp_entry_t’ {aka ‘struct <anonymous>’} from type ‘int’
arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
^
./include/linux/swapops.h:84:9: error: implicit declaration of function ‘__swp_entry_to_pte’; did you mean ‘swp_entry_to_pte’? [-Werror=implicit-function-declaration]
return __swp_entry_to_pte(arch_entry);
^~~~~~~~~~~~~~~~~~
swp_entry_to_pte
./include/linux/swapops.h:84:9: error: incompatible types when returning type ‘int’ but ‘pte_t’ {aka ‘struct <anonymous>’} was expected
return __swp_entry_to_pte(arch_entry);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
make[1]: *** [scripts/Makefile.build:278: mm/vmscan.o] Error 1
make: *** [Makefile:1071: mm] Error 2
make: *** Waiting for unfinished jobs....
On 6/11/19 3:18 PM, Christoph Hellwig wrote:
> On Tue, Jun 11, 2019 at 11:15:44AM +0100, Vladimir Murzin wrote:
>> On 6/10/19 11:16 PM, Christoph Hellwig wrote:
>>> The whole header file deals with swap entries and PTEs, none of which
>>> can exist for nommu builds.
>>
>> Although I agree with the patch, I'm wondering how you get into it?
>
> Without that the RISC-V nommu blows up like this:
>
>
> In file included from mm/vmscan.c:58:
> ./include/linux/swapops.h: In function ‘pte_to_swp_entry’:
> ./include/linux/swapops.h:71:15: error: implicit declaration of function ‘__pte_to_swp_entry’; did you mean ‘pte_to_swp_entry’? [-Werror=implicit-function-declaration]
> arch_entry = __pte_to_swp_entry(pte);
> ^~~~~~~~~~~~~~~~~~
> pte_to_swp_entry
> ./include/linux/swapops.h:71:13: error: incompatible types when assigning to type ‘swp_entry_t’ {aka ‘struct <anonymous>’} from type ‘int’
> arch_entry = __pte_to_swp_entry(pte);
> ^
> ./include/linux/swapops.h:72:19: error: implicit declaration of function ‘__swp_type’; did you mean ‘swp_type’? [-Werror=implicit-function-declaration]
> return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
> ^~~~~~~~~~
> swp_type
> ./include/linux/swapops.h:72:43: error: implicit declaration of function ‘__swp_offset’; did you mean ‘swp_offset’? [-Werror=implicit-function-declaration]
> return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
> ^~~~~~~~~~~~
> swp_offset
> ./include/linux/swapops.h: In function ‘swp_entry_to_pte’:
> ./include/linux/swapops.h:83:15: error: implicit declaration of function ‘__swp_entry’; did you mean ‘swp_entry’? [-Werror=implicit-function-declaration]
> arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
> ^~~~~~~~~~~
> swp_entry
> ./include/linux/swapops.h:83:13: error: incompatible types when assigning to type ‘swp_entry_t’ {aka ‘struct <anonymous>’} from type ‘int’
> arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
> ^
> ./include/linux/swapops.h:84:9: error: implicit declaration of function ‘__swp_entry_to_pte’; did you mean ‘swp_entry_to_pte’? [-Werror=implicit-function-declaration]
> return __swp_entry_to_pte(arch_entry);
> ^~~~~~~~~~~~~~~~~~
> swp_entry_to_pte
> ./include/linux/swapops.h:84:9: error: incompatible types when returning type ‘int’ but ‘pte_t’ {aka ‘struct <anonymous>’} was expected
> return __swp_entry_to_pte(arch_entry);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
> make[1]: *** [scripts/Makefile.build:278: mm/vmscan.o] Error 1
> make: *** [Makefile:1071: mm] Error 2
> make: *** Waiting for unfinished jobs....
>
It looks like NOMMU ports tend to define those. For ARM they are:
#define __swp_type(x) (0)
#define __swp_offset(x) (0)
#define __swp_entry(typ,off) ((swp_entry_t) { ((typ) | ((off) << 7)) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
Anyway, I have no strong opinion on which is better :)
Cheers
Vladimir
On Tue, Jun 11, 2019 at 03:36:53PM +0100, Vladimir Murzin wrote:
> It looks like NOMMU ports tend to define those. For ARM they are:
>
> #define __swp_type(x) (0)
> #define __swp_offset(x) (0)
> #define __swp_entry(typ,off) ((swp_entry_t) { ((typ) | ((off) << 7)) })
> #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
> #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
>
> Anyway, I have no strong opinion on which is better :)
It just seems a lot easier to stub out swapops.h rather than providing
stubs in each arch so that inlines which we are never going to use can
build. I can look into dropping this from the other nommu ports for
the next merge window, though.