Re: [RFC v5 054/126] virtio-9p: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

19.11.2019 19:56, Greg Kurz wrote:
> Sorry for the late review...
> 
> On Fri, 11 Oct 2019 19:04:40 +0300
> Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> wrote:
> 
>> If we want to add some info to errp (by error_prepend() or
>> error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
>> Otherwise, this info will not be added when errp == &fatal_err
> 
> s/fatal_err/error_fatal/
> 
>> (the program will exit prior to the error_append_hint() or
>> error_prepend() call).  Fix such cases.
>>
>> If we want to check error after errp-function call, we need to
>> introduce local_err and than propagate it to errp. Instead, use
> 
> s/than/then
> 
>> ERRP_AUTO_PROPAGATE macro, benefits are:
>> 1. No need of explicit error_propagate call
>> 2. No need of explicit local_err variable: use errp directly
>> 3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
>>     &error_fatel, this means that we don't break error_abort
> 
> s/error_fatel/error_fatal
> 
>>     (we'll abort on error_set, not on error_propagate)
>>
>> This commit (together with its neighbors) was generated by
>>
>> for f in $(git grep -l errp \*.[ch]); do \
>>      spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
>>      --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
>> done;
>>
>> then fix a bit of compilation problems: coccinelle for some reason
>> leaves several
>> f() {
>>      ...
>>      goto out;
>>      ...
>>      out:
>> }
>> patterns, with "out:" at function end.
>>
>> then
>> ./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"
>>
>> (auto-msg was a file with this commit message)
>>
>> Still, for backporting it may be more comfortable to use only the first
>> command and then do one huge commit.
>>
>> Reported-by: Kevin Wolf <kwolf@redhat.com>
>> Reported-by: Greg Kurz <groug@kaod.org>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   hw/9pfs/9p-local.c | 8 ++++----
>>   hw/9pfs/9p.c       | 1 +
>>   2 files changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
>> index 35635e7e7e..aac7989f16 100644
>> --- a/hw/9pfs/9p-local.c
>> +++ b/hw/9pfs/9p-local.c
>> @@ -1477,9 +1477,9 @@ static void error_append_security_model_hint(Error **errp_in)
>>   
>>   static int local_parse_opts(QemuOpts *opts, FsDriverEntry *fse, Error **errp)
>>   {
>> +    ERRP_AUTO_PROPAGATE();
>>       const char *sec_model = qemu_opt_get(opts, "security_model");
>>       const char *path = qemu_opt_get(opts, "path");
>> -    Error *local_err = NULL;
>>   
>>       if (!sec_model) {
>>           error_setg(errp, "security_model property not set");
>> @@ -1507,9 +1507,9 @@ static int local_parse_opts(QemuOpts *opts, FsDriverEntry *fse, Error **errp)
>>           return -1;
>>       }
>>   
>> -    fsdev_throttle_parse_opts(opts, &fse->fst, &local_err);
>> -    if (local_err) {
>> -        error_propagate_prepend(errp, local_err,
>> +    fsdev_throttle_parse_opts(opts, &fse->fst, errp);
>> +    if (*errp) {
>> +        error_prepend(errp,
>>                                   "invalid throttle configuration: ");
> 
> The change looks good, apart from the funky indentation.
> 
>>           return -1;
>>       }
>> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
>> index cce2366219..1df2749e03 100644
>> --- a/hw/9pfs/9p.c
>> +++ b/hw/9pfs/9p.c
>> @@ -3552,6 +3552,7 @@ void pdu_submit(V9fsPDU *pdu, P9MsgHeader *hdr)
>>   int v9fs_device_realize_common(V9fsState *s, const V9fsTransport *t,
>>                                  Error **errp)
>>   {
>> +    ERRP_AUTO_PROPAGATE();
> 
> I don't know coccinelle so I'm not sure why ERRP_AUTO_PROPAGATE() was
> added here... but it's definitely not needed in this function.


Because this function calls error_prepend()

> 
>>       int i, len;
>>       struct stat stat;
>>       FsDriverEntry *fse;
> 


-- 
Best regards,
Vladimir