[lttng-dev] [PATCH lttng-modules] Fix: kref changes for kernel 4.11

[Mathieu Desnoyers]

----- On Mar 7, 2017, at 11:37 PM, Francis Deslauriers francis.deslauriers at efficios.com wrote:

> The underlying type of `struct kref` changed in kernel 4.11 from an
> atomic_t to a refcount_t. This change was introduced in kernel
> commit:10383ae. This commit also added a builtin overflow checks to
> `kref_get()` so we use it.
> 
> Signed-off-by: Francis Deslauriers <francis.deslauriers at efficios.com>
> ---
> wrapper/kref.h | 8 ++++++++
> 1 file changed, 8 insertions(+)
> 
> diff --git a/wrapper/kref.h b/wrapper/kref.h
> index f30a9ae..8db05b5 100644
> --- a/wrapper/kref.h
> +++ b/wrapper/kref.h
> @@ -34,9 +34,17 @@
>  *
>  * Return 1 if reference is taken, 0 otherwise (overflow).
>  */
> +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0))

Don't forget to include 

#include <linux/version.h>

I'll add it locally as I merge it into master and 2.9.

Thanks,

Mathieu

> +static inline int lttng_kref_get(struct kref *kref)
> +{
> +	kref_get(kref);
> +	return 1;
> +}
> +#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
> static inline int lttng_kref_get(struct kref *kref)
> {
> 	return atomic_add_unless(&kref->refcount, 1, INT_MAX);
> }
> +#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */
> 
> #endif /* _LTTNG_WRAPPER_KREF_H */
> --
> 2.7.4

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com