On 13/10/2016 13:14, Marc-André Lureau wrote:
> Hi,
>
> Commit 949055a2 "char: use a fixed idx for child muxed chr" introduced
> a regression in mux usage, since it wrongly interpreted mux as muxing
> various chr backend. Instead, it muxes frontends.
>
> The first patch reverts the broken change, the following patches add
> tracking to frontend handler, finally the last patch adds some tests
> that would have helped to track the crash and the regression. There is
> also a small fix for ringbuf.
In general I like the solution, but I dislike the API.
Would it work if we had something like
struct CharBackend {
CharDriverState *chr;
int tag;
}
and we modified all qemu_chr_fe_* functions (plus
qemu_chr_add_handlers[1]) to take a struct CharBackend. chardev
properties would also take a struct CharBackend. Then removing handlers
can still be done in release_chr, making the patches much smaller.
The conversion is a bit tedious, but I think it's much easier compared
to patch 4. I feel bad for having you redo everything and in particular
patch 7, but this is the model that the block layer uses and it works
very well there.
[1] while at it, it's probably best to rename qemu_chr_add_handlers
to qemu_chr_fe_add_handlers as the first patch in the series,
so that qemu_chr_add_handlers(CharDriverState *chr, ..., int tag)
can take the role of qemu_chr_set_handlers in this series.
Thanks,
Paolo
