Re: [dpdk-dev] [dpdk-stable] [PATCH] drivers/crypto: fix gcc 10 no-common errors

["Hemant Agrawal (OSS)" <hemant.agrawal@oss.nxp.com>]

> On 5/13/2020 2:50 PM, akhil.goyal@nxp.com wrote:
> > From: Akhil Goyal <akhil.goyal@nxp.com>
> >
> > gcc 10 defaults to -fno-common and as a result when linking with
> > crypto drivers:
> >
> > drivers/librte_pmd_dpaa_sec.a(crypto_dpaa_sec_dpaa_sec.c.o):
> > (.bss+0x4): multiple definition of `rta_sec_era';
> > drivers/librte_pmd_caam_jr.a(crypto_caam_jr_caam_jr.c.o):
> > (.bss+0x0): first defined here
> >
> > drivers/librte_pmd_dpaa2_sec.a(crypto_dpaa2_sec_dpaa2_sec_dpseci.c.o):
> > (.data+0x0): multiple definition of `rta_sec_era';
> > drivers/librte_pmd_caam_jr.a(crypto_caam_jr_caam_jr.c.o):
> > (.bss+0x0): first defined here
> >
> > This patch fixes the blunt workaround in the following commit.
> >
> > Fixes: 50b03f3b8eaf ("drivers/crypto: disable gcc 10 no-common
> > errors")
> >
> > Bugzilla ID: 469
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Akhil Goyal <akhil.goyal@nxp.com>
> 
> +1, this is better approach, and tested with gcc10.
> 
> Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>
> 
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
> 
> Instead of having 3 seperate global variables for three seperate PMDs, now
> there is a single global variable.
> In static build these three variables were already used as single variable, that is
> why we are getting fcommon warning, so I assume there is no use case to use
> multiple of these PMDs at the same time, but previously this was fine (each
> PMD has its own variable) when built as shared library, now shared library is
> also using single variable.
> It can be good to verify with PMD maintainers that this is OK, and these PMDs
> won't be used at the same time in a platform.
[Hemant] This variable represent the SEC HW revision for a given platform. So it will not be different irrespective of drivers being used. 
Yes, for a given platform, only one PMD will be used at a given time.