Re: [PATCH v6 01/13] libxl: change ao_device_remove to ao_device

[Roger Pau Monne <roger.pau@citrix.com>]

Ian Jackson wrote:
> Roger Pau Monne writes ("[PATCH v6 01/13] libxl: change ao_device_remove to ao_device"):
>> Introduce a new structure to track state of device backends, that will
>> be used in following patches on this series.
> ...
>
> Looks good.  I have only one comment:
>
>> +static void device_xsentries_remove(libxl__egc *egc, libxl__ao_device *aodev)
>> +{
>> +    STATE_AO_GC(aodev->ao);
>> +    char *be_path = libxl__device_backend_path(gc, aodev->dev);
>> +    char *fe_path = libxl__device_frontend_path(gc, aodev->dev);
>> +    xs_transaction_t t = 0;
>> +    int ret = 0;
>> +
>> +    if (aodev->action == DEVICE_DISCONNECT) {
>> +        do {
>> +            t = xs_transaction_start(CTX->xsh);
>> +            libxl__xs_path_cleanup(gc, t, fe_path);
>> +            libxl__xs_path_cleanup(gc, t, be_path);
>> +            ret = !xs_transaction_end(CTX->xsh, t, 0);
>> +        } while (ret&&  errno == EAGAIN);
>
> The error handling here seems a bit lacking.  Perhaps you should
> import my "[PATCH 08/21] libxl: provide libxl__xs_*_checked ..." into
> your series and use those ?  You can see an example of how they're
> used in "[PATCH 09/21] libxl: wait for qemu to acknowledge logdirty
> command".

Is it possible to change this part of the code after you have committed 
your series? If you want I can send a patch to fix this so you can add 
it at the end of your series.

> And you need to check the return values from libxl__xs_path_cleanup.

Even if I check the return value from libxl__xs_path_cleanup I will only 
print an error message, but the logic of the function will not change, 
and the error message it's already printed by libxl__xs_path_cleanup. If 
front or back xenstore entries remove failed, I will still try to remove 
the other entries and commit the transaction.

Thanks for the review.

Roger.