Re: [PATCH v6 08/11] virtio-9p: introduce ERRP_AUTO_PROPAGATE

[Greg Kurz <groug@kaod.org>]

On Fri, 10 Jan 2020 22:41:55 +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 == &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 then propagate it to errp. Instead, use
> 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_fatal, this means that we don't break error_abort
>    (we'll abort on error_set, not on error_propagate)
> 
> This commit is generated by command
> 
>     sed -n '/^virtio-9p$/,/^$/{s/^F: //p}' MAINTAINERS | \
>     xargs git ls-files | grep '\.[hc]$' | \
>     xargs spatch \
>         --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
>         --macro-file scripts/cocci-macro-file.h \
>         --in-place --no-show-diff --max-width 80
> 
> Reported-by: Kevin Wolf <kwolf@redhat.com>
> Reported-by: Greg Kurz <groug@kaod.org>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---

Acked-by: Greg Kurz <groug@kaod.org>

>  hw/9pfs/9p-local.c | 12 +++++-------
>  hw/9pfs/9p.c       |  1 +
>  2 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> index ca641390fb..253814ef2c 100644
> --- a/hw/9pfs/9p-local.c
> +++ b/hw/9pfs/9p-local.c
> @@ -1481,10 +1481,10 @@ static void error_append_security_model_hint(Error *const *errp)
>  
>  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");
>      const char *multidevs = qemu_opt_get(opts, "multidevs");
> -    Error *local_err = NULL;
>  
>      if (!sec_model) {
>          error_setg(errp, "security_model property not set");
> @@ -1518,11 +1518,10 @@ static int local_parse_opts(QemuOpts *opts, FsDriverEntry *fse, Error **errp)
>              fse->export_flags &= ~V9FS_FORBID_MULTIDEVS;
>              fse->export_flags &= ~V9FS_REMAP_INODES;
>          } else {
> -            error_setg(&local_err, "invalid multidevs property '%s'",
> +            error_setg(errp, "invalid multidevs property '%s'",
>                         multidevs);
> -            error_append_hint(&local_err, "Valid options are: multidevs="
> +            error_append_hint(errp, "Valid options are: multidevs="
>                                "[remap|forbid|warn]\n");
> -            error_propagate(errp, local_err);
>              return -1;
>          }
>      }
> @@ -1532,9 +1531,8 @@ static int local_parse_opts(QemuOpts *opts, FsDriverEntry *fse, Error **errp)
>          return -1;
>      }
>  
> -    if (fsdev_throttle_parse_opts(opts, &fse->fst, &local_err)) {
> -        error_propagate_prepend(errp, local_err,
> -                                "invalid throttle configuration: ");
> +    if (fsdev_throttle_parse_opts(opts, &fse->fst, errp)) {
> +        error_prepend(errp, "invalid throttle configuration: ");
>          return -1;
>      }
>  
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 520177f40c..4200c3416b 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -3994,6 +3994,7 @@ void pdu_submit(V9fsPDU *pdu, P9MsgHeader *hdr)
>  int v9fs_device_realize_common(V9fsState *s, const V9fsTransport *t,
>                                 Error **errp)
>  {
> +    ERRP_AUTO_PROPAGATE();
>      int i, len;
>      struct stat stat;
>      FsDriverEntry *fse;