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

[Greg Kurz]

Sorry for the late review...

On Fri, 11 Oct 2019 19:04:40 +0300
Vladimir Sementsov-Ogievskiy <address@hidden> 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 <address@hidden>
> Reported-by: Greg Kurz <address@hidden>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> ---
>  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.

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