Re: [PATCH v1] gpudev: return EINVAL if invalid input pointer for free and unregister

[Thomas Monjalon <thomas@monjalon.net>]

19/11/2021 10:34, Ferruh Yigit:
> On 11/18/2021 8:19 PM, Tyler Retzlaff wrote:
> > On Thu, Nov 18, 2021 at 07:28:02PM +0000, eagostini@nvidia.com wrote:
> >> From: Elena Agostini <eagostini@nvidia.com>
> >>
> >> Signed-off-by: Elena Agostini <eagostini@nvidia.com>
> >> ---
> >>   lib/gpudev/gpudev.c     | 10 ++++++++++
> >>   lib/gpudev/rte_gpudev.h |  2 ++
> >>   2 files changed, 12 insertions(+)
> >>
> >> diff --git a/lib/gpudev/gpudev.c b/lib/gpudev/gpudev.c
> >> index 2b174d8bd5..97575ed979 100644
> >> --- a/lib/gpudev/gpudev.c
> >> +++ b/lib/gpudev/gpudev.c
> >> @@ -576,6 +576,11 @@ rte_gpu_mem_free(int16_t dev_id, void *ptr)
> >>   		return -rte_errno;
> >>   	}
> >>   
> >> +	if (ptr == NULL) {
> >> +		rte_errno = EINVAL;
> >> +		return -rte_errno;
> >> +	}
> > 
> > in general dpdk has real problems with how it indicates that an error
> > occurred and what error occurred consistently.
> > 
> > some api's return 0 on success
> >    and maybe return -errno if ! 0
> >    and maybe return errno if ! 0

Which function returns a positive errno?

> >    and maybe set rte_errno if ! 0
> > 
> > some api's return -1 on failure
> >    and set rte_errno if -1
> > 
> > some api's return < 0 on failure
> >    and maybe set rte_errno
> >    and maybe return -errno
> >    and maybe set rte_errno and return -rte_errno
> 
> This is a generic comment, cc'ed a few more folks to make the comment more
> visible.
> 
> > this isn't isiolated to only this change but since additions and context
> > in this patch highlight it maybe it's a good time to bring it up.
> > 
> > it's frustrating to have to carefully read the implementation every time
> > you want to make a function call to make sure you're handling the flavor
> > of error reporting for a particular function.
> > 
> > if this is new code could we please clearly identify the current best
> > practice and follow it as a standard going forward for all new public
> > apis.

I think this patch is following the best practice.
1/ Return negative value in case of error
2/ Set rte_errno
3/ Set same absolute value in rte_errno and return code