[dpdk-dev] [PATCH v2] net/i40e: remove weak symbols

Ferruh Yigit ferruh.yigit at intel.com
Wed Sep 14 15:42:47 CEST 2016


On 7/20/2016 6:11 PM, Zoltan Kiss wrote:
> Using weak symbols have a few issues with static linking:
> 
> - normally the linker searches the .o files already linked, if your weak
>   one is there, it won't check if there is a strong version
> - unless the symbol is directly referred, but it's not the right thing to
>   rely on
> - or --whole-archive specified in the command line, which pulls in a lot
>   of unwanted stuff
> - whole-archive also makes libtool dropping the library from the command
>   line, which is what should happen with dynamic linking, but not with
>   static (observed on Ubuntu 14.04). This is an important bug if you
>   build a static library depending on DPDK
> 
> This patch merges the two version and make the behaviour rely on the
> config.
> 
> If we can agree in the concept, I can send a series to fix this for the
> other weak functions.
> 
> Signed-off-by: Zoltan Kiss <zoltan.kiss at schaman.hu>
> ---

+ i40e maintainers

I personally prefer macros against weak symbols, because dpdk can be
compiled as static and dynamic libraries, and weak symbols are not
working fine when compiled as static.

> 
> Notes:
>     v2: fix commit message
> 
>  drivers/net/i40e/i40e_rxtx.c     | 36 +++++++++++++++++++++++++++++++++++-
>  drivers/net/i40e/i40e_rxtx_vec.c | 36 ------------------------------------
>  2 files changed, 35 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
> index d3cfb98..ad34d3a 100644
> --- a/drivers/net/i40e/i40e_rxtx.c
> +++ b/drivers/net/i40e/i40e_rxtx.c
> @@ -3278,10 +3278,44 @@ i40e_set_tx_function(struct rte_eth_dev *dev)
>  }
> 
>  /* Stubs needed for linkage when CONFIG_RTE_I40E_INC_VECTOR is set to 'n' */
> -int __attribute__((weak))
> +int __attribute__((cold))
>  i40e_rx_vec_dev_conf_condition_check(struct rte_eth_dev __rte_unused *dev)
>  {
> +#ifndef RTE_LIBRTE_I40E_INC_VECTOR
>         return -1;
> +#else

This moves all vector implementation into non-vector file, this is bad
for maintaining. Why not:

in i40e_rxtx.c:
#ifndef RTE_LIBRTE_I40E_INC_VECTOR
i40e_rx_vec_dev_conf_condition_check()
{
	return -1;
}
#endif

in i40e_rxtx_vec.c:
No change, keep i40e_rx_vec_dev_conf_condition_check() as it is.

Thanks,
ferruh


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