[lttng-dev] [PATCH lttng-modules] Fix: build failure on 2.6.36

[Mathieu Desnoyers]

----- On Aug 29, 2015, at 1:03 PM, Michael Jeanson mjeanson at efficios.com wrote:

> Fixes build failure on the 2.6.36 kernel branch which misses the
> vzalloc() function.
> 
> Signed-off-by: Michael Jeanson <mjeanson at efficios.com>
> ---
> lttng-events.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
> 
> diff --git a/lttng-events.c b/lttng-events.c
> index b49851b..422a2dd 100644
> --- a/lttng-events.c
> +++ b/lttng-events.c
> @@ -133,7 +133,12 @@ struct lttng_session *lttng_session_create(void)
> 			GFP_KERNEL);
> 	if (!metadata_cache)
> 		goto err_free_session;
> +#if LTTNG_KERNEL_RANGE(2,6,36, 2,6,37)
> +	metadata_cache->data = vmalloc(METADATA_CACHE_DEFAULT_SIZE);
> +	memset(metadata_cache->data, 0, METADATA_CACHE_DEFAULT_SIZE);

You need to test whether vmalloc returned NULL before writing
to it.

Moreover, I'm against putting such preprocessor conditionals
in the code. We should create a wrapper header for vzalloc
implementing lttng_vzalloc instead.

Thanks,

Mathieu

> +#else
> 	metadata_cache->data = vzalloc(METADATA_CACHE_DEFAULT_SIZE);
> +#endif
> 	if (!metadata_cache->data)
> 		goto err_free_cache;
> 	metadata_cache->cache_alloc = METADATA_CACHE_DEFAULT_SIZE;
> @@ -1531,7 +1536,12 @@ int lttng_metadata_printf(struct lttng_session *session,
> 		tmp_cache_alloc_size = max_t(unsigned int,
> 				session->metadata_cache->cache_alloc + len,
> 				session->metadata_cache->cache_alloc << 1);
> +#if LTTNG_KERNEL_RANGE(2,6,36, 2,6,37)
> +		tmp_cache_realloc = vmalloc(tmp_cache_alloc_size);
> +		memset(tmp_cache_realloc, 0, tmp_cache_alloc_size);
> +#else
> 		tmp_cache_realloc = vzalloc(tmp_cache_alloc_size);
> +#endif
> 		if (!tmp_cache_realloc)
> 			goto err;
> 		if (session->metadata_cache->data) {
> --
> 1.9.1

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