Re: [PATCH v6 3/5] misc: fastrpc: Add support for context Invoke method

[Srinivas Kandagatla]

On 08/02/2019 14:11, Greg KH wrote:
> > On 08/02/2019 13:55, Greg KH wrote:
> > > > +
> > > > +		/* Make sure reserved field is set to 0 */
> > > > +		if (args->reserved) {
> > > > +			kfree(args);
> > > > +			return -EINVAL;
> > > Am I wrong in that you are only checking the first reserved field in
> > > this array of args?  Don't you have a whole bunch of them here (nscalars
> > > of them)?  Don't you need to check them all and not just the first one?
> > My Bad, there should be a loop here!
> > I will fix this in next version!
> No, you don't need to loop it here, check it in the call that evaluates
> the individual args, which will catch the issue when people send
> "internal" commands.
Yes, that makes more sense. We can avoid a loop here and do the check in 
 fastrpc_get_args().

> Which reminds me, what happens if a sequence has problems half way
> through the list of args?  Do you "roll back" to the beginning, or just
> abort?  What happens to the internal device state then?

We should abort the invoke if this check fails.

All the arguments are passed in a single invoke call to dsp, so if the 
sanity fails we should not even attempt to send it to dsp.

fastrpc_context_put in fastrpc_internal_invoke() should take care of any 
mappings created half way thru this checks.

--srini