2020-12-23 03:17:44

by Souptick Joarder

Subject: [PATCH] mm: add prototype for __add_to_page_cache_locked()

Otherwise it causes a gcc warning:

../mm/filemap.c:830:14: warning: no previous prototype for
`__add_to_page_cache_locked' [-Wmissing-prototypes]

A previous attempt to make this function static led to compilation
errors when CONFIG_DEBUG_INFO_BTF is enabled because
__add_to_page_cache_locked() is referred to by BPF code.

Adding a prototype will silence the warning.

Signed-off-by: Souptick Joarder <[email protected]>
Cc: Alex Shi <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Matthew Wilcox <[email protected]>
---
include/linux/mm.h | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5299b90a..c1e9081 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -216,6 +216,13 @@ int overcommit_kbytes_handler(struct ctl_table *, int, void *, size_t *,
loff_t *);
int overcommit_policy_handler(struct ctl_table *, int, void *, size_t *,
loff_t *);
+/*
+ * Any attempt to mark this function as static leads to build failure
+ * when CONFIG_DEBUG_INFO_BTF is enabled because __add_to_page_cache_locked()
+ * is referred to by BPF code. This must be visible for error injection.
+ */
+int __add_to_page_cache_locked(struct page *page, struct address_space *mapping,
+ pgoff_t index, gfp_t gfp, void **shadowp);

#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))

--
1.9.1

2020-12-23 03:20:25

by Souptick Joarder

Subject: Re: [PATCH] mm: add prototype for __add_to_page_cache_locked()

On Wed, Dec 23, 2020 at 8:46 AM Souptick Joarder <[email protected]> wrote:
>
> Otherwise it causes a gcc warning:
>
> ../mm/filemap.c:830:14: warning: no previous prototype for
> `__add_to_page_cache_locked' [-Wmissing-prototypes]
>
> A previous attempt to make this function static led to compilation
> errors when CONFIG_DEBUG_INFO_BTF is enabled because
> __add_to_page_cache_locked() is referred to by BPF code.
>
> Adding a prototype will silence the warning.
>

Please ignore this patch. I forget to update version.

> Signed-off-by: Souptick Joarder <[email protected]>
> Cc: Alex Shi <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Matthew Wilcox <[email protected]>
> ---
> include/linux/mm.h | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 5299b90a..c1e9081 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -216,6 +216,13 @@ int overcommit_kbytes_handler(struct ctl_table *, int, void *, size_t *,
> loff_t *);
> int overcommit_policy_handler(struct ctl_table *, int, void *, size_t *,
> loff_t *);
> +/*
> + * Any attempt to mark this function as static leads to build failure
> + * when CONFIG_DEBUG_INFO_BTF is enabled because __add_to_page_cache_locked()
> + * is referred to by BPF code. This must be visible for error injection.
> + */
> +int __add_to_page_cache_locked(struct page *page, struct address_space *mapping,
> + pgoff_t index, gfp_t gfp, void **shadowp);
>
> #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
>
> --
> 1.9.1
>