From: "De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
To: "Gaëtan Rivet" <gaetan.rivet@6wind.com>,
"Neil Horman" <nhorman@tuxdriver.com>
Cc: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>,
Akhil Goyal <akhil.goyal@nxp.com>,
"Doherty, Declan" <declan.doherty@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH 2/3] crypto: fix pedentic compilation errors
Date: Wed, 22 Nov 2017 16:50:59 +0000 [thread overview]
Message-ID: <E115CCD9D858EF4F90C690B0DCB4D8976CC4C767@IRSMSX108.ger.corp.intel.com> (raw)
In-Reply-To: <20171122143151.y5f44gnmy25t5sq2@bidouze.vm.6wind.com>
> -----Original Message-----
> From: Gaëtan Rivet [mailto:gaetan.rivet@6wind.com]
> Sent: Wednesday, November 22, 2017 2:32 PM
> To: Neil Horman <nhorman@tuxdriver.com>
> Cc: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>; Akhil Goyal
> <akhil.goyal@nxp.com>; Doherty, Declan <declan.doherty@intel.com>;
> dev@dpdk.org; De Lara Guarch, Pablo <pablo.de.lara.guarch@intel.com>;
> stable@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH 2/3] crypto: fix pedentic compilation errors
>
> On Wed, Nov 22, 2017 at 08:56:14AM -0500, Neil Horman wrote:
> > On Wed, Nov 22, 2017 at 09:10:17AM +0100, Nelio Laranjeiro wrote:
> > > /root/dpdk/x86_64-native-linuxapp-gcc/include/rte_crypto.h:126:28:
> error: ISO C forbids zero-size array ‘sym’ [-Werror=pedantic]
> > > struct rte_crypto_sym_op sym[0];
> > > ^~~
> > >
> > > Fixes: d2a4223c4c6d ("cryptodev: do not store pointer to op specific
> > > params")
> > > Cc: pablo.de.lara.guarch@intel.com
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
> > > ---
> > > lib/librte_cryptodev/rte_crypto.h | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/lib/librte_cryptodev/rte_crypto.h
> > > b/lib/librte_cryptodev/rte_crypto.h
> > > index 3d672fe7d..dc6e91d1d 100644
> > > --- a/lib/librte_cryptodev/rte_crypto.h
> > > +++ b/lib/librte_cryptodev/rte_crypto.h
> > > @@ -123,7 +123,7 @@ struct rte_crypto_op {
> > >
> > > RTE_STD_C11
> > > union {
> > > - struct rte_crypto_sym_op sym[0];
> > > + struct rte_crypto_sym_op *sym;
> > > /**< Symmetric operation parameters */
> > > }; /**< operation specific parameters */ };
> > > --
> > > 2.11.0
> > >
> > >
> > As Laura notes, this isn't the right solution. In addition to adding a 64 bit
> > pointer, it I think also results in incorrect semantics. That is to say, the
> > allocation path for this structure allocates the rte_crypto_op and
> additional
> > memory for the sym array contiguously, which the sym[0] syntax
> correctly
> > interprets to mean the storage for the array is inline with the structure.
> > Changing to a pointer means you are using the first elements of the array
> > storage as your pointer, which could be filled with any old value, leading
> to
> > corruption.
> >
> > If you can't use zero length array semantics (which I assume you cant, as I
> > don't think clang supports that), a better soution might be to remove the
> sym
> > variable entirely, and replace it with a macro that access the sym array as
> an
> > offset from the start of the pointer. That would seem to be an ABI
> change, but
> > if you went through that process you would wind up with the same sized
> struct,
> > which would be nice
> >
> > Neil
> >
>
> ISO C forbids zero-size arrays, but ISO C99 allows flexible arrays.
> Why is this symbole within a union? Why not remove the union, change
> sym[0] to sym[]?
It is a union because there were going to be other types of crypto operations (might still happen in the future).
For instance:
union{
struct rte_crypto_sym_op sym[0];
struct rte_crypto_asym_op asym[0];
}
Thanks,
Pablo
>
> --
> Gaëtan Rivet
> 6WIND
next prev parent reply other threads:[~2017-11-22 16:51 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-22 8:10 [dpdk-stable] [PATCH 1/3] security: fix device operation type Nelio Laranjeiro
2017-11-22 8:10 ` [dpdk-stable] [PATCH 2/3] crypto: fix pedentic compilation errors Nelio Laranjeiro
2017-11-22 9:48 ` De Lara Guarch, Pablo
2017-11-22 10:35 ` Nelio Laranjeiro
2017-11-22 13:56 ` [dpdk-stable] [dpdk-dev] " Neil Horman
2017-11-22 14:31 ` Gaëtan Rivet
2017-11-22 16:50 ` De Lara Guarch, Pablo [this message]
2017-11-22 8:10 ` [dpdk-stable] [PATCH 3/3] security: fix pedentic compilation Nelio Laranjeiro
2017-11-23 10:02 ` [dpdk-stable] [PATCH v2 1/3] security: fix device operation type Nelio Laranjeiro
2017-11-24 9:33 ` Akhil Goyal
2017-11-24 12:07 ` Nelio Laranjeiro
2018-01-08 9:58 ` De Lara Guarch, Pablo
2018-01-08 10:05 ` Akhil Goyal
2018-01-08 12:34 ` De Lara Guarch, Pablo
2017-11-23 10:02 ` [dpdk-stable] [PATCH v2 2/3] crypto: fix pedantic compilation errors Nelio Laranjeiro
2017-12-11 11:49 ` De Lara Guarch, Pablo
2017-12-11 12:42 ` Nelio Laranjeiro
2017-12-11 13:54 ` De Lara Guarch, Pablo
2017-12-11 14:16 ` Nelio Laranjeiro
2018-01-08 10:00 ` [dpdk-stable] [dpdk-dev] " De Lara Guarch, Pablo
2018-01-08 12:35 ` [dpdk-stable] " De Lara Guarch, Pablo
2017-11-23 10:02 ` [dpdk-stable] [PATCH v2 3/3] security: fix pedantic compilation Nelio Laranjeiro
2017-11-24 9:34 ` Akhil Goyal
2018-01-08 12:35 ` De Lara Guarch, Pablo
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