Re: [PATCH 1/1] split-ring: clarify the field len in the used ring

[Cornelia Huck <cohuck@redhat.com>]

On Fri, Nov 26 2021, Halil Pasic <pasic@linux.ibm.com> wrote:

> The current descriptor is misleading: "the descriptor chain which was
> used" generally includes both the descriptors that map the device read
> only, and descriptors that  map the device write only portions of the
> buffer described by the descriptor chain. The argument that "used" means
> "written to" does not stand because one has to "use" the descriptor
> chain even when the whole buffer is device read only.
>
> One can argue, that the most straightforward way to interpret the phrase
> "total length of that descriptor chain" (without context) like the
> length of the  list is usually defined: i.e. like the number of
> descriptors that constitute the chain. This is clearly not what we want
> here. Another intuitive way to interpret "total length of that
> descriptor chain" is size of the buffer mapped by the descriptor chain.
> This is not what we want either. In fact such wrongful interpretations
> have caused bugs in the wild.
>
> On the other hand, the text below the listing that gets modified here
> clearly describes the semantics of \field{len}. So let us replace
> the ambiguous explanation in the listing, with a hopefully non-ambiguous
> one.
>
> Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
> ---
>  split-ring.tex | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

Thanks, pushed as an editorial update.