Re: [PATCH] lttng-module: block.h : Fix build for 3.9 kernel

[Mathieu Desnoyers <mathieu.desnoyers@efficios.com>]

* maxin.john@enea.com (maxin.john@enea.com) wrote:
> From: "Maxin B. John" <maxin.john@enea.com>
> 
> commit :3a366e614d0837d9fc23f78cdb1a1186ebc3387f
>  block: add missing block_bio_complete() tracepoint
> added block_bio_complete to 3.9 kernel
> 
> commit : 8c1cf6bb02fda79b0a4b9bd121f6be6d4ce7a15a
>  block: add @req to bio_{front|back}_merge tracepoints
> added block_bio_backmerge and block_bio_frontmerge to 3.9 kernel
> 
> Update block.h based on these commits in mainline kernel

Disabling the event prior to 3.9.0 does not seem to be the proper
solution. We should rather #ifdef the old/new TRACE_EVENT definitions to
accept the proper number of arguments for each kernel.

Thanks,

Mathieu

> 
> Fixes this build failure:
> ....
> include/trace/events/block.h:353:1: note: previous definition of
> 'trace_block_bio_frontmerge' was here
> make[3]: *** [/home/majo/kernel/lttng/lttng-modules/probes/
> lttng-probe-block.o] Error 1
> make[2]: *** [/home/majo/kernel/lttng/lttng-modules/probes] Error 2
> make[1]: *** [_module_/home/majo/kernel/lttng/lttng-modules] Error 2
> make: *** [default] Error 2
> 
> Signed-off-by: Maxin B. John <maxin.john@enea.com>
> ---
>  instrumentation/events/lttng-module/block.h |   16 ++++++++++++++++
>  1 files changed, 16 insertions(+), 0 deletions(-)
> 
> diff --git a/instrumentation/events/lttng-module/block.h b/instrumentation/events/lttng-module/block.h
> index d42ebd4..59bd2c0 100644
> --- a/instrumentation/events/lttng-module/block.h
> +++ b/instrumentation/events/lttng-module/block.h
> @@ -311,6 +311,13 @@ TRACE_EVENT(block_bio_bounce,
>   * This tracepoint indicates there is no further work to do on this
>   * block IO operation @bio.
>   */
> +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0))
> +/**
> + * commit :3a366e614d0837d9fc23f78cdb1a1186ebc3387f
> + * block: add missing block_bio_complete() tracepoint
> + * added block_bio_complete to 3.9.0 kernel
> + */
> +#else
>  TRACE_EVENT(block_bio_complete,
>  
>  #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,38))
> @@ -349,6 +356,7 @@ TRACE_EVENT(block_bio_complete,
>  		  (unsigned long long)__entry->sector,
>  		  __entry->nr_sector, __entry->error)
>  )
> +#endif
>  
>  DECLARE_EVENT_CLASS(block_bio,
>  
> @@ -387,6 +395,13 @@ DECLARE_EVENT_CLASS(block_bio,
>   * Merging block request @bio to the end of an existing block request
>   * in queue @q.
>   */
> +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,9,0))
> +/**
> + * commit : 8c1cf6bb02fda79b0a4b9bd121f6be6d4ce7a15a
> + * block: add @req to bio_{front|back}_merge tracepoints
> + * added block_bio_backmerge and block_bio_frontmerge to 3.9.0 kernel
> + */
> +#else
>  DEFINE_EVENT(block_bio, block_bio_backmerge,
>  
>  	TP_PROTO(struct request_queue *q, struct bio *bio),
> @@ -408,6 +423,7 @@ DEFINE_EVENT(block_bio, block_bio_frontmerge,
>  
>  	TP_ARGS(q, bio)
>  )
> +#endif
>  
>  /**
>   * block_bio_queue - putting new block IO operation in queue
> -- 
> 1.7.5.4
> 

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