On Thu, 2005-05-19 at 03:23, Michael S. Tsirkin wrote: > Quoting r. Roland Dreier <[EMAIL PROTECTED]>: > > Subject: Re: [RFC] [PATCH] user_mad: Support RMPP on send side > > > > This looks OK to check in with one small comment on the following: > > > > - if (copy_to_user(buf, &packet->mad, sizeof packet->mad)) > > + if (copy_to_user(buf, &packet->mad, > > + min(count, packet->length + > > + sizeof (struct ib_user_mad)))) > > ret = -EFAULT; > > else > > - ret = sizeof packet->mad; > > + ret = count; > > > > This code will truncate a received MAD that is bigger than the buffer > > passed into read(), but return the full size of the packet. I don't > > think read() is allowed to do this: the return value can be at most > > the count value passed in by the user. > > > > I think we have two options: truncate and return the actual amount of > > data read to the user, or return an error if the user's buffer is too > > small. > > > > - R. > > > > If you truncate, how will the user know the MAD was truncated?
The length returned. Roland is saying to fix it is one option (rather than ret = count). I'm now questioning whether that is useful behavior. Would a subsequent read get the next part of the packet and the user piece them together ? If not, then this should be an error for this case (which is the second option). I am leaning towards that unless someone has an objection to that behavior. -- Hal _______________________________________________ openib-general mailing list openib-general@openib.org http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
