Re: [dpdk-dev] [dpdk-stable] [PATCH] crypto/qat: fix uninitilized compiler warning

[David Marchand <david.marchand@redhat.com>]

On Fri, May 14, 2021 at 10:01 AM Feifei Wang <Feifei.Wang2@arm.com> wrote:
> > > @@ -1190,8 +1190,8 @@ static int partial_hash_compute(enum
> > icp_qat_hw_auth_algo hash_alg,
> > >                         uint8_t *data_out)  {
> > >         int digest_size;
> > > -       uint8_t digest[qat_hash_get_digest_size(
> > > -                       ICP_QAT_HW_AUTH_ALGO_DELIMITER)];
> > > +       uint8_t *digest = (uint8_t *)calloc(qat_hash_get_digest_size(
> > > +                               ICP_QAT_HW_AUTH_ALGO_DELIMITER),
> > > + sizeof(uint8_t));
> >
> > calloc can fail.
> > cast is unneded.
> >
> > A simple uint8_t digest[...] = { 0 } would do the job.
>
> Thanks for your comment. Actually, we have tried to use this simple method:
>  uint8_t digest[qat_hash_get_digest_size(ICP_QAT_HW_AUTH_ALGO_DELIMITER)] = {0};
>
> And it will report compile error:
> ../drivers/crypto/qat/qat_sym_session.c:1194:4: error: variable-sized object may not be initialized
>  1194 |    ICP_QAT_HW_AUTH_ALGO_DELIMITER)] = {0};
>       |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../drivers/crypto/qat/qat_sym_session.c:1194:40: warning: excess elements in array initializer
>  1194 |    ICP_QAT_HW_AUTH_ALGO_DELIMITER)] = {0};
>       |                                        ^
> ../drivers/crypto/qat/qat_sym_session.c:1194:40: note: (near initialization for ‘digest’)
> ninja: build stopped: subcommand failed.
>
> I think this is because compiler cannot know the size of digest due to function
> 'qat_hash_get_digest_size' during  compiling time.

Ok, I had not noticed the function call.

Please check dynamic allocation succeeds.
+ free this temp buffer before leaving this helper function.


-- 
David marchand