[PATCH v6 00/11] error: auto propagated local_err part I

[PATCH v6 00/11] error: auto propagated local_err part I

[Vladimir Sementsov-Ogievskiy]

Hi all!

Now, when preparations from
 [RFC v5 000/126] error: auto propagated local_err
 https://lists.gnu.org/archive/html/qemu-devel/2019-10/msg02771.html
 https://src.openvz.org/scm/~vsementsov/qemu.git #tag up-auto-local-err-v5 
, after some iterations, are finally merged, let's proceed with the
rest. Sorry for a big delay on my part.

As a first step, I decided to take subsystems, each of them covered by
one patch, which get r-b/a-b marks by maintainer of the subsystem in v5.

v6 is available at
 https://src.openvz.org/scm/~vsementsov/qemu.git #tag up-auto-local-err-partI-v6 

Changes v5->v6:
01: use errp name for the parameter, add assertion
02: add a lot of text information, drop Eric's r-b.
    no semantic changes.
03: add more comments
    skip functions with pattern error_append_.*_hint in name
    make errp identifier, to match any name of Error ** paramter
    some other improvements
04: only commit message changed,
    keep Philippe's r-b
05: new, manual update for hw/sd/ssi-sd
06: only commit message changed,
    keep Philippe's r-b
07: only commit message changed,
    keep Philippe's r-b
08: local_parse_opts() changed, so patch changed in this
    function, drop a-b mark
    also, indentation fixed, by improvement in coccinelle script
09: only commit message changed,
    keep Stefan's r-b
10: commit message and a bit of context changed, still seems
    valid to keep Eric's r-b
11: add new hunk: hw/pci-host/xen_igd_pt.c, so, drop r-b
    also, indentation fixed, by improvement in coccinelle script

In these series, there is no commit-per-subsystem script, each generated
commit is generated in separate.

Still, generating commands are very similar, and looks like

    sed -n '/^<Subsystem name>$/,/^$/{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

Note, that in each generated commit, generation command is the only
text, indented by 8 spaces in 'git log -1' output, so, to regenerate all
commits (for example, after rebase, or change in coccinelle script), you
may use the following command:

git rebase -x "sh -c \"git show --pretty= --name-only | xargs git checkout HEAD^ -- ; git reset; git log -1 | grep '^        ' | sh\"" HEAD~7

Which will start automated interactive rebase for generated patches,
which will stop if generated patch changed
(you may do git commit --amend to apply updated generated changes).

Note:
  git show --pretty= --name-only   - lists files, changed in HEAD
  git log -1 | grep '^        ' | sh   - rerun generation command of HEAD


Check for compilation of changed .c files
git rebase -x "sh -c \"git show --pretty= --name-only | sed -n 's/\.c$/.o/p' | xargs make -j9\"" HEAD~7
  

Vladimir Sementsov-Ogievskiy (11):
  qapi/error: add (Error **errp) cleaning APIs
  error: auto propagated local_err
  scripts: add coccinelle script to use auto propagated errp
  hw/sd/ssi-sd: fix error handling in ssi_sd_realize
  SD (Secure Card): introduce ERRP_AUTO_PROPAGATE
  pflash: introduce ERRP_AUTO_PROPAGATE
  fw_cfg: introduce ERRP_AUTO_PROPAGATE
  virtio-9p: introduce ERRP_AUTO_PROPAGATE
  TPM: introduce ERRP_AUTO_PROPAGATE
  nbd: introduce ERRP_AUTO_PROPAGATE
  xen: introduce ERRP_AUTO_PROPAGATE

 include/block/nbd.h                           |   1 +
 include/qapi/error.h                          | 113 +++++++++++++-
 block/nbd.c                                   |  49 +++---
 hw/9pfs/9p-local.c                            |  12 +-
 hw/9pfs/9p.c                                  |   1 +
 hw/block/dataplane/xen-block.c                |  17 +--
 hw/block/pflash_cfi01.c                       |   7 +-
 hw/block/pflash_cfi02.c                       |   7 +-
 hw/block/xen-block.c                          | 125 +++++++---------
 hw/nvram/fw_cfg.c                             |  14 +-
 hw/pci-host/xen_igd_pt.c                      |   7 +-
 hw/sd/sdhci-pci.c                             |   7 +-
 hw/sd/sdhci.c                                 |  21 ++-
 hw/sd/ssi-sd.c                                |  26 +++-
 hw/tpm/tpm_util.c                             |   7 +-
 hw/xen/xen-backend.c                          |   7 +-
 hw/xen/xen-bus.c                              | 100 ++++++-------
 hw/xen/xen-host-pci-device.c                  |  27 ++--
 hw/xen/xen_pt.c                               |  25 ++--
 hw/xen/xen_pt_config_init.c                   |  20 +--
 nbd/client.c                                  |   5 +
 nbd/server.c                                  |   5 +
 tpm.c                                         |   7 +-
 scripts/coccinelle/auto-propagated-errp.cocci | 139 ++++++++++++++++++
 24 files changed, 482 insertions(+), 267 deletions(-)
 create mode 100644 scripts/coccinelle/auto-propagated-errp.cocci

CC: Cornelia Huck <cohuck@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Greg Kurz <groug@kaod.org>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Anthony Perard <anthony.perard@citrix.com>
CC: Paul Durrant <paul@xen.org>
CC: "Philippe Mathieu-Daudé" <philmd@redhat.com>
CC: Laszlo Ersek <lersek@redhat.com>
CC: Gerd Hoffmann <kraxel@redhat.com>
CC: Stefan Berger <stefanb@linux.ibm.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
CC: qemu-block@nongnu.org
CC: xen-devel@lists.xenproject.org

-- 
2.21.0

[PATCH v6 01/11] qapi/error: add (Error **errp) cleaning APIs

[Vladimir Sementsov-Ogievskiy]

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---

CC: Cornelia Huck <cohuck@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Greg Kurz <groug@kaod.org>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Anthony Perard <anthony.perard@citrix.com>
CC: Paul Durrant <paul@xen.org>
CC: "Philippe Mathieu-Daudé" <philmd@redhat.com>
CC: Laszlo Ersek <lersek@redhat.com>
CC: Gerd Hoffmann <kraxel@redhat.com>
CC: Stefan Berger <stefanb@linux.ibm.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
CC: qemu-block@nongnu.org
CC: xen-devel@lists.xenproject.org

 include/qapi/error.h | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/include/qapi/error.h b/include/qapi/error.h
index ad5b6e896d..fa8d51fd6d 100644
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -309,6 +309,32 @@ void warn_reportf_err(Error *err, const char *fmt, ...)
 void error_reportf_err(Error *err, const char *fmt, ...)
     GCC_FMT_ATTR(2, 3);
 
+/*
+ * Functions to clean Error **errp: call corresponding Error *err cleaning
+ * function an set pointer to NULL
+ */
+static inline void error_free_errp(Error **errp)
+{
+    assert(errp && *errp);
+    error_free(*errp);
+    *errp = NULL;
+}
+
+static inline void error_report_errp(Error **errp)
+{
+    assert(errp && *errp);
+    error_report_err(*errp);
+    *errp = NULL;
+}
+
+static inline void warn_report_errp(Error **errp)
+{
+    assert(errp && *errp);
+    warn_report_err(*errp);
+    *errp = NULL;
+}
+
+
 /*
  * Just like error_setg(), except you get to specify the error class.
  * Note: use of error classes other than ERROR_CLASS_GENERIC_ERROR is
-- 
2.21.0

Re: [PATCH v6 01/11] qapi/error: add (Error **errp) cleaning APIs

[Greg Kurz]

On Fri, 10 Jan 2020 22:41:48 +0300
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> wrote:

> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
> 

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

> CC: Cornelia Huck <cohuck@redhat.com>
> CC: Eric Blake <eblake@redhat.com>
> CC: Kevin Wolf <kwolf@redhat.com>
> CC: Max Reitz <mreitz@redhat.com>
> CC: Greg Kurz <groug@kaod.org>
> CC: Stefan Hajnoczi <stefanha@redhat.com>
> CC: Stefano Stabellini <sstabellini@kernel.org>
> CC: Anthony Perard <anthony.perard@citrix.com>
> CC: Paul Durrant <paul@xen.org>
> CC: "Philippe Mathieu-Daudé" <philmd@redhat.com>
> CC: Laszlo Ersek <lersek@redhat.com>
> CC: Gerd Hoffmann <kraxel@redhat.com>
> CC: Stefan Berger <stefanb@linux.ibm.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Michael Roth <mdroth@linux.vnet.ibm.com>
> CC: qemu-block@nongnu.org
> CC: xen-devel@lists.xenproject.org
> 
>  include/qapi/error.h | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/include/qapi/error.h b/include/qapi/error.h
> index ad5b6e896d..fa8d51fd6d 100644
> --- a/include/qapi/error.h
> +++ b/include/qapi/error.h
> @@ -309,6 +309,32 @@ void warn_reportf_err(Error *err, const char *fmt, ...)
>  void error_reportf_err(Error *err, const char *fmt, ...)
>      GCC_FMT_ATTR(2, 3);
>  
> +/*
> + * Functions to clean Error **errp: call corresponding Error *err cleaning
> + * function an set pointer to NULL
> + */
> +static inline void error_free_errp(Error **errp)
> +{
> +    assert(errp && *errp);
> +    error_free(*errp);
> +    *errp = NULL;
> +}
> +
> +static inline void error_report_errp(Error **errp)
> +{
> +    assert(errp && *errp);
> +    error_report_err(*errp);
> +    *errp = NULL;
> +}
> +
> +static inline void warn_report_errp(Error **errp)
> +{
> +    assert(errp && *errp);
> +    warn_report_err(*errp);
> +    *errp = NULL;
> +}
> +
> +
>  /*
>   * Just like error_setg(), except you get to specify the error class.
>   * Note: use of error classes other than ERROR_CLASS_GENERIC_ERROR is

Re: [PATCH v6 01/11] qapi/error: add (Error **errp) cleaning APIs

[Eric Blake]

On 1/10/20 1:41 PM, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---

Sparse commit message; it might be nice (for future 'git log' 
greppability) to at least mention the names of the functions being added.

>   
> +/*
> + * Functions to clean Error **errp: call corresponding Error *err cleaning
> + * function an set pointer to NULL

s/ an/, then/

Missing a '.' at the end of the sentence.

Otherwise,
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

[PATCH v6 02/11] error: auto propagated local_err

[Vladimir Sementsov-Ogievskiy]

Here is introduced ERRP_AUTO_PROPAGATE macro, to be used at start of
functions with errp OUT parameter.

It has three goals:

1. Fix issue with error_fatal & error_prepend/error_append_hint: user
can't see this additional information, because exit() happens in
error_setg earlier than information is added. [Reported by Greg Kurz]

2. Fix issue with error_abort & error_propagate: when we wrap
error_abort by local_err+error_propagate, resulting coredump will
refer to error_propagate and not to the place where error happened.
(the macro itself doesn't fix the issue, but it allows to [3.] drop all
local_err+error_propagate pattern, which will definitely fix the issue)
[Reported by Kevin Wolf]

3. Drop local_err+error_propagate pattern, which is used to workaround
void functions with errp parameter, when caller wants to know resulting
status. (Note: actually these functions could be merely updated to
return int error code).

To achieve these goals, we need to add invocation of the macro at start
of functions, which needs error_prepend/error_append_hint (1.); add
invocation of the macro at start of functions which do
local_err+error_propagate scenario the check errors, drop local errors
from them and just use *errp instead (2., 3.).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---

CC: Cornelia Huck <cohuck@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Greg Kurz <groug@kaod.org>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Anthony Perard <anthony.perard@citrix.com>
CC: Paul Durrant <paul@xen.org>
CC: "Philippe Mathieu-Daudé" <philmd@redhat.com>
CC: Laszlo Ersek <lersek@redhat.com>
CC: Gerd Hoffmann <kraxel@redhat.com>
CC: Stefan Berger <stefanb@linux.ibm.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
CC: qemu-block@nongnu.org
CC: xen-devel@lists.xenproject.org

 include/qapi/error.h | 84 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 83 insertions(+), 1 deletion(-)

diff --git a/include/qapi/error.h b/include/qapi/error.h
index fa8d51fd6d..532b9afb9e 100644
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -78,7 +78,7 @@
  * Call a function treating errors as fatal:
  *     foo(arg, &error_fatal);
  *
- * Receive an error and pass it on to the caller:
+ * Receive an error and pass it on to the caller (DEPRECATED*):
  *     Error *err = NULL;
  *     foo(arg, &err);
  *     if (err) {
@@ -98,6 +98,50 @@
  *     foo(arg, errp);
  * for readability.
  *
+ * DEPRECATED* This pattern is deprecated now, use ERRP_AUTO_PROPAGATE macro
+ * instead (defined below).
+ * It's deprecated because of two things:
+ *
+ * 1. Issue with error_abort & error_propagate: when we wrap error_abort by
+ * local_err+error_propagate, resulting coredump will refer to error_propagate
+ * and not to the place where error happened.
+ *
+ * 2. A lot of extra code of the same pattern
+ *
+ * How to update old code to use ERRP_AUTO_PROPAGATE?
+ *
+ * All you need is to add ERRP_AUTO_PROPAGATE() invocation at function start,
+ * than you may safely dereference errp to check errors and do not need any
+ * additional local Error variables or calls to error_propagate().
+ *
+ * Example:
+ *
+ * old code
+ *
+ *     void fn(..., Error **errp) {
+ *         Error *err = NULL;
+ *         foo(arg, &err);
+ *         if (err) {
+ *             handle the error...
+ *             error_propagate(errp, err);
+ *             return;
+ *         }
+ *         ...
+ *     }
+ *
+ * updated code
+ *
+ *     void fn(..., Error **errp) {
+ *         ERRP_AUTO_PROPAGATE();
+ *         foo(arg, errp);
+ *         if (*errp) {
+ *             handle the error...
+ *             return;
+ *         }
+ *         ...
+ *     }
+ *
+ *
  * Receive and accumulate multiple errors (first one wins):
  *     Error *err = NULL, *local_err = NULL;
  *     foo(arg, &err);
@@ -348,6 +392,44 @@ void error_set_internal(Error **errp,
                         ErrorClass err_class, const char *fmt, ...)
     GCC_FMT_ATTR(6, 7);
 
+typedef struct ErrorPropagator {
+    Error *local_err;
+    Error **errp;
+} ErrorPropagator;
+
+static inline void error_propagator_cleanup(ErrorPropagator *prop)
+{
+    error_propagate(prop->errp, prop->local_err);
+}
+
+G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(ErrorPropagator, error_propagator_cleanup);
+
+/*
+ * ERRP_AUTO_PROPAGATE
+ *
+ * This macro is created to be the first line of a function which use
+ * Error **errp parameter to report error. It's needed only in cases where we
+ * want to use error_prepend, error_append_hint or dereference *errp. It's
+ * still safe (but useless) in other cases.
+ *
+ * If errp is NULL or points to error_fatal, it is rewritten to point to a
+ * local Error object, which will be automatically propagated to the original
+ * errp on function exit (see error_propagator_cleanup).
+ *
+ * After invocation of this macro it is always safe to dereference errp
+ * (as it's not NULL anymore) and to add information (by error_prepend or
+ * error_append_hint)
+ * (as, if it was error_fatal, we swapped it with a local_error to be
+ * propagated on cleanup).
+ *
+ * Note: we don't wrap the error_abort case, as we want resulting coredump
+ * to point to the place where the error happened, not to error_propagate.
+ */
+#define ERRP_AUTO_PROPAGATE()                                  \
+    g_auto(ErrorPropagator) _auto_errp_prop = {.errp = errp};  \
+    errp = ((errp == NULL || *errp == error_fatal)             \
+            ? &_auto_errp_prop.local_err : errp)
+
 /*
  * Special error destination to abort on error.
  * See error_setg() and error_propagate() for details.
-- 
2.21.0

Re: [PATCH v6 02/11] error: auto propagated local_err

[Paul Durrant]

On Fri, 10 Jan 2020 at 19:42, Vladimir Sementsov-Ogievskiy
<vsementsov@virtuozzo.com> wrote:
[snip]
> +/*
> + * ERRP_AUTO_PROPAGATE
> + *
> + * This macro is created to be the first line of a function which use
> + * Error **errp parameter to report error. It's needed only in cases where we
> + * want to use error_prepend, error_append_hint or dereference *errp. It's
> + * still safe (but useless) in other cases.
> + *
> + * If errp is NULL or points to error_fatal, it is rewritten to point to a
> + * local Error object, which will be automatically propagated to the original
> + * errp on function exit (see error_propagator_cleanup).
> + *
> + * After invocation of this macro it is always safe to dereference errp
> + * (as it's not NULL anymore) and to add information (by error_prepend or
> + * error_append_hint)
> + * (as, if it was error_fatal, we swapped it with a local_error to be
> + * propagated on cleanup).
> + *
> + * Note: we don't wrap the error_abort case, as we want resulting coredump
> + * to point to the place where the error happened, not to error_propagate.
> + */
> +#define ERRP_AUTO_PROPAGATE()                                  \
> +    g_auto(ErrorPropagator) _auto_errp_prop = {.errp = errp};  \
> +    errp = ((errp == NULL || *errp == error_fatal)             \

Perhaps !errp rather than errp == NULL, for brevity.

  Paul

> +            ? &_auto_errp_prop.local_err : errp)
> +
>  /*
>   * Special error destination to abort on error.
>   * See error_setg() and error_propagate() for details.
> --
> 2.21.0
>

Re: [PATCH v6 02/11] error: auto propagated local_err

[Vladimir Sementsov-Ogievskiy]

13.01.2020 11:50, Paul Durrant wrote:
> On Fri, 10 Jan 2020 at 19:42, Vladimir Sementsov-Ogievskiy
> <vsementsov@virtuozzo.com> wrote:
> [snip]
>> +/*
>> + * ERRP_AUTO_PROPAGATE
>> + *
>> + * This macro is created to be the first line of a function which use
>> + * Error **errp parameter to report error. It's needed only in cases where we
>> + * want to use error_prepend, error_append_hint or dereference *errp. It's
>> + * still safe (but useless) in other cases.
>> + *
>> + * If errp is NULL or points to error_fatal, it is rewritten to point to a
>> + * local Error object, which will be automatically propagated to the original
>> + * errp on function exit (see error_propagator_cleanup).
>> + *
>> + * After invocation of this macro it is always safe to dereference errp
>> + * (as it's not NULL anymore) and to add information (by error_prepend or
>> + * error_append_hint)
>> + * (as, if it was error_fatal, we swapped it with a local_error to be
>> + * propagated on cleanup).
>> + *
>> + * Note: we don't wrap the error_abort case, as we want resulting coredump
>> + * to point to the place where the error happened, not to error_propagate.
>> + */
>> +#define ERRP_AUTO_PROPAGATE()                                  \
>> +    g_auto(ErrorPropagator) _auto_errp_prop = {.errp = errp};  \
>> +    errp = ((errp == NULL || *errp == error_fatal)             \
> 
> Perhaps !errp rather than errp == NULL, for brevity.
> 

I mostly prefer !ptr notation.. But may be here, I'd keep it as is,
to stress special-casing NULL in this non-trivial place.. And it is in good
relation with phrasing "If errp is NULL or points to error_fatal".
But !errp is OK for me to. Let it be as Markus prefer, he is maintainer.

> 
>> +            ? &_auto_errp_prop.local_err : errp)
>> +
>>   /*
>>    * Special error destination to abort on error.
>>    * See error_setg() and error_propagate() for details.
>> --
>> 2.21.0
>>


-- 
Best regards,
Vladimir

Re: [PATCH v6 02/11] error: auto propagated local_err

[Greg Kurz]

On Fri, 10 Jan 2020 22:41:49 +0300
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> wrote:

> Here is introduced ERRP_AUTO_PROPAGATE macro, to be used at start of
> functions with errp OUT parameter.
> 
> It has three goals:
> 
> 1. Fix issue with error_fatal & error_prepend/error_append_hint: user
> can't see this additional information, because exit() happens in
> error_setg earlier than information is added. [Reported by Greg Kurz]
> 
> 2. Fix issue with error_abort & error_propagate: when we wrap
> error_abort by local_err+error_propagate, resulting coredump will
> refer to error_propagate and not to the place where error happened.
> (the macro itself doesn't fix the issue, but it allows to [3.] drop all
> local_err+error_propagate pattern, which will definitely fix the issue)
> [Reported by Kevin Wolf]
> 
> 3. Drop local_err+error_propagate pattern, which is used to workaround
> void functions with errp parameter, when caller wants to know resulting
> status. (Note: actually these functions could be merely updated to
> return int error code).
> 
> To achieve these goals, we need to add invocation of the macro at start
> of functions, which needs error_prepend/error_append_hint (1.); add
> invocation of the macro at start of functions which do
> local_err+error_propagate scenario the check errors, drop local errors
> from them and just use *errp instead (2., 3.).
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
> 

LGTM

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

> CC: Cornelia Huck <cohuck@redhat.com>
> CC: Eric Blake <eblake@redhat.com>
> CC: Kevin Wolf <kwolf@redhat.com>
> CC: Max Reitz <mreitz@redhat.com>
> CC: Greg Kurz <groug@kaod.org>
> CC: Stefan Hajnoczi <stefanha@redhat.com>
> CC: Stefano Stabellini <sstabellini@kernel.org>
> CC: Anthony Perard <anthony.perard@citrix.com>
> CC: Paul Durrant <paul@xen.org>
> CC: "Philippe Mathieu-Daudé" <philmd@redhat.com>
> CC: Laszlo Ersek <lersek@redhat.com>
> CC: Gerd Hoffmann <kraxel@redhat.com>
> CC: Stefan Berger <stefanb@linux.ibm.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Michael Roth <mdroth@linux.vnet.ibm.com>
> CC: qemu-block@nongnu.org
> CC: xen-devel@lists.xenproject.org
> 
>  include/qapi/error.h | 84 +++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 83 insertions(+), 1 deletion(-)
> 
> diff --git a/include/qapi/error.h b/include/qapi/error.h
> index fa8d51fd6d..532b9afb9e 100644
> --- a/include/qapi/error.h
> +++ b/include/qapi/error.h
> @@ -78,7 +78,7 @@
>   * Call a function treating errors as fatal:
>   *     foo(arg, &error_fatal);
>   *
> - * Receive an error and pass it on to the caller:
> + * Receive an error and pass it on to the caller (DEPRECATED*):
>   *     Error *err = NULL;
>   *     foo(arg, &err);
>   *     if (err) {
> @@ -98,6 +98,50 @@
>   *     foo(arg, errp);
>   * for readability.
>   *
> + * DEPRECATED* This pattern is deprecated now, use ERRP_AUTO_PROPAGATE macro
> + * instead (defined below).
> + * It's deprecated because of two things:
> + *
> + * 1. Issue with error_abort & error_propagate: when we wrap error_abort by
> + * local_err+error_propagate, resulting coredump will refer to error_propagate
> + * and not to the place where error happened.
> + *
> + * 2. A lot of extra code of the same pattern
> + *
> + * How to update old code to use ERRP_AUTO_PROPAGATE?
> + *
> + * All you need is to add ERRP_AUTO_PROPAGATE() invocation at function start,
> + * than you may safely dereference errp to check errors and do not need any
> + * additional local Error variables or calls to error_propagate().
> + *
> + * Example:
> + *
> + * old code
> + *
> + *     void fn(..., Error **errp) {
> + *         Error *err = NULL;
> + *         foo(arg, &err);
> + *         if (err) {
> + *             handle the error...
> + *             error_propagate(errp, err);
> + *             return;
> + *         }
> + *         ...
> + *     }
> + *
> + * updated code
> + *
> + *     void fn(..., Error **errp) {
> + *         ERRP_AUTO_PROPAGATE();
> + *         foo(arg, errp);
> + *         if (*errp) {
> + *             handle the error...
> + *             return;
> + *         }
> + *         ...
> + *     }
> + *
> + *
>   * Receive and accumulate multiple errors (first one wins):
>   *     Error *err = NULL, *local_err = NULL;
>   *     foo(arg, &err);
> @@ -348,6 +392,44 @@ void error_set_internal(Error **errp,
>                          ErrorClass err_class, const char *fmt, ...)
>      GCC_FMT_ATTR(6, 7);
>  
> +typedef struct ErrorPropagator {
> +    Error *local_err;
> +    Error **errp;
> +} ErrorPropagator;
> +
> +static inline void error_propagator_cleanup(ErrorPropagator *prop)
> +{
> +    error_propagate(prop->errp, prop->local_err);
> +}
> +
> +G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(ErrorPropagator, error_propagator_cleanup);
> +
> +/*
> + * ERRP_AUTO_PROPAGATE
> + *
> + * This macro is created to be the first line of a function which use
> + * Error **errp parameter to report error. It's needed only in cases where we
> + * want to use error_prepend, error_append_hint or dereference *errp. It's
> + * still safe (but useless) in other cases.
> + *
> + * If errp is NULL or points to error_fatal, it is rewritten to point to a
> + * local Error object, which will be automatically propagated to the original
> + * errp on function exit (see error_propagator_cleanup).
> + *
> + * After invocation of this macro it is always safe to dereference errp
> + * (as it's not NULL anymore) and to add information (by error_prepend or
> + * error_append_hint)
> + * (as, if it was error_fatal, we swapped it with a local_error to be
> + * propagated on cleanup).
> + *
> + * Note: we don't wrap the error_abort case, as we want resulting coredump
> + * to point to the place where the error happened, not to error_propagate.
> + */
> +#define ERRP_AUTO_PROPAGATE()                                  \
> +    g_auto(ErrorPropagator) _auto_errp_prop = {.errp = errp};  \
> +    errp = ((errp == NULL || *errp == error_fatal)             \
> +            ? &_auto_errp_prop.local_err : errp)
> +
>  /*
>   * Special error destination to abort on error.
>   * See error_setg() and error_propagate() for details.

Re: [PATCH v6 02/11] error: auto propagated local_err

[Eric Blake]

On 1/10/20 1:41 PM, Vladimir Sementsov-Ogievskiy wrote:
> Here is introduced ERRP_AUTO_PROPAGATE macro, to be used at start of
> functions with errp OUT parameter.

s/with/with an/

> 
> It has three goals:
> 
> 1. Fix issue with error_fatal & error_prepend/error_append_hint: user

maybe s/&/and/ so it doesn't look like the C & operator.

> can't see this additional information, because exit() happens in
> error_setg earlier than information is added. [Reported by Greg Kurz]
> 
> 2. Fix issue with error_abort & error_propagate: when we wrap

and again

> error_abort by local_err+error_propagate, resulting coredump will

s/,/, the/

> refer to error_propagate and not to the place where error happened.
> (the macro itself doesn't fix the issue, but it allows to [3.] drop all

s/allows/allows us/
s/all/the/

> local_err+error_propagate pattern, which will definitely fix the issue)
> [Reported by Kevin Wolf]
> 
> 3. Drop local_err+error_propagate pattern, which is used to workaround
> void functions with errp parameter, when caller wants to know resulting
> status. (Note: actually these functions could be merely updated to
> return int error code).
> 
> To achieve these goals, we need to add invocation of the macro at start
> of functions, which needs error_prepend/error_append_hint (1.); add
> invocation of the macro at start of functions which do
> local_err+error_propagate scenario the check errors, drop local errors
> from them and just use *errp instead (2., 3.).

To achieve these goals, later patches will add invocations of this macro 
at the start of functions with either use 
error_prepend/error_append_hint (solving 1) or which use 
local_err+error_propagate to check errors, switching those functions to 
use *errp instead (solving 2 and 3).

> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
> 

> - * Receive an error and pass it on to the caller:
> + * Receive an error and pass it on to the caller (DEPRECATED*):
>    *     Error *err = NULL;
>    *     foo(arg, &err);
>    *     if (err) {
> @@ -98,6 +98,50 @@
>    *     foo(arg, errp);
>    * for readability.
>    *
> + * DEPRECATED* This pattern is deprecated now, use ERRP_AUTO_PROPAGATE macro

s/use/use the/

> + * instead (defined below).
> + * It's deprecated because of two things:
> + *
> + * 1. Issue with error_abort & error_propagate: when we wrap error_abort by

s/&/and/

> + * local_err+error_propagate, resulting coredump will refer to error_propagate

s/,/, the/

> + * and not to the place where error happened.
> + *
> + * 2. A lot of extra code of the same pattern
> + *

> +/*
> + * ERRP_AUTO_PROPAGATE
> + *
> + * This macro is created to be the first line of a function which use
> + * Error **errp parameter to report error. It's needed only in cases where we
> + * want to use error_prepend, error_append_hint or dereference *errp. It's
> + * still safe (but useless) in other cases.

It doesn't _have_ to be the first line to compile (we require C99+ 
compilers, which allow declarations after statements); but rather 
because it makes it easier for our Coccinelle conversion script to catch 
outliers.  But I think this text is okay, without calling out that extra 
information (maybe the commit message should mention it, though).

> + *
> + * If errp is NULL or points to error_fatal, it is rewritten to point to a
> + * local Error object, which will be automatically propagated to the original
> + * errp on function exit (see error_propagator_cleanup).
> + *
> + * After invocation of this macro it is always safe to dereference errp
> + * (as it's not NULL anymore) and to add information (by error_prepend or
> + * error_append_hint)
> + * (as, if it was error_fatal, we swapped it with a local_error to be
> + * propagated on cleanup).

double () () looks odd, as does the mid-sentence newline.

> + *
> + * Note: we don't wrap the error_abort case, as we want resulting coredump
> + * to point to the place where the error happened, not to error_propagate.
> + */
> +#define ERRP_AUTO_PROPAGATE()                                  \
> +    g_auto(ErrorPropagator) _auto_errp_prop = {.errp = errp};  \
> +    errp = ((errp == NULL || *errp == error_fatal)             \
> +            ? &_auto_errp_prop.local_err : errp)
> +
>   /*
>    * Special error destination to abort on error.
>    * See error_setg() and error_propagate() for details.
> 

The macro itself is fine, my comments are solely on the commit message 
and comments.  Depending on how much cleanup Markus is willing to do 
rather than require a respin, you can add:

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

[PATCH v6 03/11] scripts: add coccinelle script to use auto propagated errp

[Vladimir Sementsov-Ogievskiy]

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---

CC: Cornelia Huck <cohuck@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Greg Kurz <groug@kaod.org>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Anthony Perard <anthony.perard@citrix.com>
CC: Paul Durrant <paul@xen.org>
CC: "Philippe Mathieu-Daudé" <philmd@redhat.com>
CC: Laszlo Ersek <lersek@redhat.com>
CC: Gerd Hoffmann <kraxel@redhat.com>
CC: Stefan Berger <stefanb@linux.ibm.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
CC: qemu-block@nongnu.org
CC: xen-devel@lists.xenproject.org

 include/qapi/error.h                          |   3 +
 scripts/coccinelle/auto-propagated-errp.cocci | 139 ++++++++++++++++++
 2 files changed, 142 insertions(+)
 create mode 100644 scripts/coccinelle/auto-propagated-errp.cocci

diff --git a/include/qapi/error.h b/include/qapi/error.h
index 532b9afb9e..dcfb77e107 100644
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -141,6 +141,9 @@
  *         ...
  *     }
  *
+ * For mass conversion use script
+ *   scripts/coccinelle/auto-propagated-errp.cocci
+ *
  *
  * Receive and accumulate multiple errors (first one wins):
  *     Error *err = NULL, *local_err = NULL;
diff --git a/scripts/coccinelle/auto-propagated-errp.cocci b/scripts/coccinelle/auto-propagated-errp.cocci
new file mode 100644
index 0000000000..6c72a5049f
--- /dev/null
+++ b/scripts/coccinelle/auto-propagated-errp.cocci
@@ -0,0 +1,139 @@
+// Use ERRP_AUTO_PROPAGATE (see include/qapi/error.h)
+//
+// Copyright (c) 2020 Virtuozzo International GmbH.
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// Usage example:
+// spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
+//  --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff \
+//  blockdev-nbd.c qemu-nbd.c {block/nbd*,nbd/*,include/block/nbd*}.[hc]
+
+@@
+// Add invocation to errp-functions where necessary
+// We should skip functions with "Error *const *errp"
+// parameter, but how to do it with coccinelle?
+// I don't know, so, I skip them by function name regex.
+// It's safe: if we not skip some functions with
+// "Error *const *errp", ERRP_AUTO_PROPAGATE invocation
+// will fail to compile, because of const violation.
+identifier fn !~ "error_append_.*_hint";
+identifier local_err, errp;
+@@
+
+ fn(..., Error **errp, ...)
+ {
++   ERRP_AUTO_PROPAGATE();
+    <+...
+        when != ERRP_AUTO_PROPAGATE();
+(
+    error_append_hint(errp, ...);
+|
+    error_prepend(errp, ...);
+|
+    Error *local_err = NULL;
+)
+    ...+>
+ }
+
+@rule1@
+// We do not inherit from previous rule, as we want to match
+// also functions, which already had ERRP_AUTO_PROPAGATE
+// invocation.
+identifier fn !~ "error_append_.*_hint";
+identifier local_err, errp;
+@@
+
+ fn(..., Error **errp, ...)
+ {
+     <...
+-    Error *local_err = NULL;
+     ...>
+ }
+
+@@
+// Handle pattern with goto, otherwise we'll finish up
+// with labels at function end which will not compile.
+identifier rule1.fn, rule1.local_err, rule1.errp;
+identifier OUT;
+@@
+
+ fn(...)
+ {
+     <...
+-    goto OUT;
++    return;
+     ...>
+- OUT:
+-    error_propagate(errp, local_err);
+ }
+
+@@
+identifier rule1.fn, rule1.local_err, rule1.errp;
+expression list args; // to reindent error_propagate_prepend
+@@
+
+ fn(...)
+ {
+     <...
+(
+-    error_free(local_err);
+-    local_err = NULL;
++    error_free_errp(errp);
+|
+-    error_free(local_err);
++    error_free_errp(errp);
+|
+-    error_report_err(local_err);
++    error_report_errp(errp);
+|
+-    warn_report_err(local_err);
++    warn_report_errp(errp);
+|
+-    error_propagate_prepend(errp, local_err, args);
++    error_prepend(errp, args);
+|
+-    error_propagate(errp, local_err);
+)
+     ...>
+ }
+
+@@
+identifier rule1.fn, rule1.local_err, rule1.errp;
+@@
+
+ fn(...)
+ {
+     <...
+(
+-    &local_err
++    errp
+|
+-    local_err
++    *errp
+)
+     ...>
+ }
+
+@@
+identifier rule1.fn, rule1.errp;
+@@
+
+ fn(...)
+ {
+     <...
+- *errp != NULL
++ *errp
+     ...>
+ }
-- 
2.21.0

Re: [PATCH v6 03/11] scripts: add coccinelle script to use auto propagated errp

[Eric Blake]

On 1/10/20 1:41 PM, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---

Rather light on the commit message. If nothing else, a comment about 
typical command-line usage would be helpful (yes, it's in the patch 
body, but sometimes I just refer to git log).

> diff --git a/include/qapi/error.h b/include/qapi/error.h
> index 532b9afb9e..dcfb77e107 100644
> --- a/include/qapi/error.h
> +++ b/include/qapi/error.h
> @@ -141,6 +141,9 @@
>    *         ...
>    *     }
>    *
> + * For mass conversion use script
> + *   scripts/coccinelle/auto-propagated-errp.cocci
> + *
>    *
>    * Receive and accumulate multiple errors (first one wins):
>    *     Error *err = NULL, *local_err = NULL;
> diff --git a/scripts/coccinelle/auto-propagated-errp.cocci b/scripts/coccinelle/auto-propagated-errp.cocci
> new file mode 100644
> index 0000000000..6c72a5049f
> --- /dev/null
> +++ b/scripts/coccinelle/auto-propagated-errp.cocci
> @@ -0,0 +1,139 @@
> +// Use ERRP_AUTO_PROPAGATE (see include/qapi/error.h)
> +//

> +// Usage example:
> +// spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
> +//  --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff \
> +//  blockdev-nbd.c qemu-nbd.c {block/nbd*,nbd/*,include/block/nbd*}.[hc]
> +
> +@@
> +// Add invocation to errp-functions where necessary
> +// We should skip functions with "Error *const *errp"
> +// parameter, but how to do it with coccinelle?
> +// I don't know, so, I skip them by function name regex.
> +// It's safe: if we not skip some functions with

s/not/did not/

> +// "Error *const *errp", ERRP_AUTO_PROPAGATE invocation
> +// will fail to compile, because of const violation.
> +identifier fn !~ "error_append_.*_hint";
> +identifier local_err, errp;
> +@@
> +
> + fn(..., Error **errp, ...)
> + {
> ++   ERRP_AUTO_PROPAGATE();
> +    <+...
> +        when != ERRP_AUTO_PROPAGATE();
> +(
> +    error_append_hint(errp, ...);
> +|
> +    error_prepend(errp, ...);
> +|
> +    Error *local_err = NULL;
> +)
> +    ...+>
> + }
> +

Looks like it should catch all functions that require adding the macro.

> +@rule1@
> +// We do not inherit from previous rule, as we want to match
> +// also functions, which already had ERRP_AUTO_PROPAGATE
> +// invocation.

Grammar suggestion:

// We want to patch error propagation in functions regardless of
// whether the function already uses ERRP_AUTO_PROPAGATE, hence
// this one does not inherit from the first rule.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

Re: [PATCH v6 03/11] scripts: add coccinelle script to use auto propagated errp

[Vladimir Sementsov-Ogievskiy]

10.01.2020 22:41, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
> 
> CC: Cornelia Huck <cohuck@redhat.com>
> CC: Eric Blake <eblake@redhat.com>
> CC: Kevin Wolf <kwolf@redhat.com>
> CC: Max Reitz <mreitz@redhat.com>
> CC: Greg Kurz <groug@kaod.org>
> CC: Stefan Hajnoczi <stefanha@redhat.com>
> CC: Stefano Stabellini <sstabellini@kernel.org>
> CC: Anthony Perard <anthony.perard@citrix.com>
> CC: Paul Durrant <paul@xen.org>
> CC: "Philippe Mathieu-Daudé" <philmd@redhat.com>
> CC: Laszlo Ersek <lersek@redhat.com>
> CC: Gerd Hoffmann <kraxel@redhat.com>
> CC: Stefan Berger <stefanb@linux.ibm.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Michael Roth <mdroth@linux.vnet.ibm.com>
> CC: qemu-block@nongnu.org
> CC: xen-devel@lists.xenproject.org
> 
>   include/qapi/error.h                          |   3 +
>   scripts/coccinelle/auto-propagated-errp.cocci | 139 ++++++++++++++++++
>   2 files changed, 142 insertions(+)
>   create mode 100644 scripts/coccinelle/auto-propagated-errp.cocci
> 
> diff --git a/include/qapi/error.h b/include/qapi/error.h
> index 532b9afb9e..dcfb77e107 100644
> --- a/include/qapi/error.h
> +++ b/include/qapi/error.h
> @@ -141,6 +141,9 @@
>    *         ...
>    *     }
>    *
> + * For mass conversion use script
> + *   scripts/coccinelle/auto-propagated-errp.cocci
> + *
>    *
>    * Receive and accumulate multiple errors (first one wins):
>    *     Error *err = NULL, *local_err = NULL;
> diff --git a/scripts/coccinelle/auto-propagated-errp.cocci b/scripts/coccinelle/auto-propagated-errp.cocci
> new file mode 100644
> index 0000000000..6c72a5049f
> --- /dev/null
> +++ b/scripts/coccinelle/auto-propagated-errp.cocci
> @@ -0,0 +1,139 @@
> +// Use ERRP_AUTO_PROPAGATE (see include/qapi/error.h)
> +//
> +// Copyright (c) 2020 Virtuozzo International GmbH.
> +//
> +// This program is free software; you can redistribute it and/or modify
> +// it under the terms of the GNU General Public License as published by
> +// the Free Software Foundation; either version 2 of the License, or
> +// (at your option) any later version.
> +//
> +// This program is distributed in the hope that it will be useful,
> +// but WITHOUT ANY WARRANTY; without even the implied warranty of
> +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +// GNU General Public License for more details.
> +//
> +// You should have received a copy of the GNU General Public License
> +// along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +//
> +// Usage example:
> +// spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
> +//  --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff \
> +//  blockdev-nbd.c qemu-nbd.c {block/nbd*,nbd/*,include/block/nbd*}.[hc]
> +
> +@@
> +// Add invocation to errp-functions where necessary
> +// We should skip functions with "Error *const *errp"
> +// parameter, but how to do it with coccinelle?
> +// I don't know, so, I skip them by function name regex.
> +// It's safe: if we not skip some functions with
> +// "Error *const *errp", ERRP_AUTO_PROPAGATE invocation
> +// will fail to compile, because of const violation.
> +identifier fn !~ "error_append_.*_hint";
> +identifier local_err, errp;

Hmm.

Note, that in new version I define errp as "identifier", which means,
that we'll match Error ** parameters with other names..

Still, our ERRP_AUTO_PROPAGATE assumes that parameter called errp, and
I'd prefere not to change it.

We can ignore this fact for now: inappropriately named errp parameter will
break compilation in ERRP_AUTO_PROPAGATE() invocation, so it's safe enough.
(Hope, there are no functions with two Error** parameters)

Or we can revert errp to be symbol again.

> +@@
> +
> + fn(..., Error **errp, ...)
> + {
> ++   ERRP_AUTO_PROPAGATE();
> +    <+...
> +        when != ERRP_AUTO_PROPAGATE();
> +(
> +    error_append_hint(errp, ...);
> +|
> +    error_prepend(errp, ...);
> +|
> +    Error *local_err = NULL;
> +)
> +    ...+>
> + }
> +
> +@rule1@
> +// We do not inherit from previous rule, as we want to match
> +// also functions, which already had ERRP_AUTO_PROPAGATE
> +// invocation.
> +identifier fn !~ "error_append_.*_hint";
> +identifier local_err, errp;
> +@@
> +
> + fn(..., Error **errp, ...)
> + {
> +     <...
> +-    Error *local_err = NULL;
> +     ...>
> + }
> +
> +@@
> +// Handle pattern with goto, otherwise we'll finish up
> +// with labels at function end which will not compile.
> +identifier rule1.fn, rule1.local_err, rule1.errp;
> +identifier OUT;
> +@@
> +
> + fn(...)
> + {
> +     <...
> +-    goto OUT;
> ++    return;
> +     ...>
> +- OUT:
> +-    error_propagate(errp, local_err);
> + }
> +
> +@@
> +identifier rule1.fn, rule1.local_err, rule1.errp;
> +expression list args; // to reindent error_propagate_prepend
> +@@
> +
> + fn(...)
> + {
> +     <...
> +(
> +-    error_free(local_err);
> +-    local_err = NULL;
> ++    error_free_errp(errp);
> +|
> +-    error_free(local_err);
> ++    error_free_errp(errp);
> +|
> +-    error_report_err(local_err);
> ++    error_report_errp(errp);
> +|
> +-    warn_report_err(local_err);
> ++    warn_report_errp(errp);
> +|
> +-    error_propagate_prepend(errp, local_err, args);
> ++    error_prepend(errp, args);
> +|
> +-    error_propagate(errp, local_err);
> +)
> +     ...>
> + }
> +
> +@@
> +identifier rule1.fn, rule1.local_err, rule1.errp;
> +@@
> +
> + fn(...)
> + {
> +     <...
> +(
> +-    &local_err
> ++    errp
> +|
> +-    local_err
> ++    *errp
> +)
> +     ...>
> + }
> +
> +@@
> +identifier rule1.fn, rule1.errp;
> +@@
> +
> + fn(...)
> + {
> +     <...
> +- *errp != NULL
> ++ *errp
> +     ...>
> + }
> 


-- 
Best regards,
Vladimir

[PATCH v6 04/11] hw/sd/ssi-sd: fix error handling in ssi_sd_realize

[Vladimir Sementsov-Ogievskiy]

It's wrong to use same err object as errp parameter for several
function calls without intermediate checking for error: we'll crash if
try to set err object twice.

Fix that, using new ERRP_AUTO_PROPAGATE macro.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 hw/sd/ssi-sd.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/hw/sd/ssi-sd.c b/hw/sd/ssi-sd.c
index 91db069212..bc44e1a0f5 100644
--- a/hw/sd/ssi-sd.c
+++ b/hw/sd/ssi-sd.c
@@ -241,10 +241,10 @@ static const VMStateDescription vmstate_ssi_sd = {
 
 static void ssi_sd_realize(SSISlave *d, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     ssi_sd_state *s = FROM_SSI_SLAVE(ssi_sd_state, d);
     DeviceState *carddev;
     DriveInfo *dinfo;
-    Error *err = NULL;
 
     qbus_create_inplace(&s->sdbus, sizeof(s->sdbus), TYPE_SD_BUS,
                         DEVICE(d), "sd-bus");
@@ -254,14 +254,26 @@ static void ssi_sd_realize(SSISlave *d, Error **errp)
     dinfo = drive_get_next(IF_SD);
     carddev = qdev_create(BUS(&s->sdbus), TYPE_SD_CARD);
     if (dinfo) {
-        qdev_prop_set_drive(carddev, "drive", blk_by_legacy_dinfo(dinfo), &err);
+        qdev_prop_set_drive(carddev, "drive", blk_by_legacy_dinfo(dinfo), errp);
+        if (*errp) {
+            goto fail;
+        }
+    }
+
+    object_property_set_bool(OBJECT(carddev), true, "spi", errp);
+    if (*errp) {
+        goto fail;
     }
-    object_property_set_bool(OBJECT(carddev), true, "spi", &err);
-    object_property_set_bool(OBJECT(carddev), true, "realized", &err);
-    if (err) {
-        error_setg(errp, "failed to init SD card: %s", error_get_pretty(err));
-        return;
+
+    object_property_set_bool(OBJECT(carddev), true, "realized", errp);
+    if (*errp) {
+        goto fail;
     }
+
+    return;
+
+fail:
+    error_prepend(errp, "failed to init SD card: ");
 }
 
 static void ssi_sd_reset(DeviceState *dev)
-- 
2.21.0

Re: [PATCH v6 04/11] hw/sd/ssi-sd: fix error handling in ssi_sd_realize

[Eric Blake]

On 1/10/20 1:41 PM, Vladimir Sementsov-Ogievskiy wrote:
> It's wrong to use same err object as errp parameter for several
> function calls without intermediate checking for error: we'll crash if
> try to set err object twice.
> 
> Fix that, using new ERRP_AUTO_PROPAGATE macro.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>   hw/sd/ssi-sd.c | 26 +++++++++++++++++++-------
>   1 file changed, 19 insertions(+), 7 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

[PATCH v6 05/11] SD (Secure Card): introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

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 '/^SD (Secure Card)$/,/^$/{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>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/sd/sdhci-pci.c |  7 +++----
 hw/sd/sdhci.c     | 21 +++++++++------------
 2 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/hw/sd/sdhci-pci.c b/hw/sd/sdhci-pci.c
index 2c8d8f59b5..b1448cf22e 100644
--- a/hw/sd/sdhci-pci.c
+++ b/hw/sd/sdhci-pci.c
@@ -29,13 +29,12 @@ static Property sdhci_pci_properties[] = {
 
 static void sdhci_pci_realize(PCIDevice *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     SDHCIState *s = PCI_SDHCI(dev);
-    Error *local_err = NULL;
 
     sdhci_initfn(s);
-    sdhci_common_realize(s, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    sdhci_common_realize(s, errp);
+    if (*errp) {
         return;
     }
 
diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
index 18c0c052ce..ca258572b3 100644
--- a/hw/sd/sdhci.c
+++ b/hw/sd/sdhci.c
@@ -1293,7 +1293,7 @@ static const MemoryRegionOps sdhci_mmio_ops = {
 
 static void sdhci_init_readonly_registers(SDHCIState *s, Error **errp)
 {
-    Error *local_err = NULL;
+    ERRP_AUTO_PROPAGATE();
 
     switch (s->sd_spec_version) {
     case 2 ... 3:
@@ -1304,9 +1304,8 @@ static void sdhci_init_readonly_registers(SDHCIState *s, Error **errp)
     }
     s->version = (SDHC_HCVER_VENDOR << 8) | (s->sd_spec_version - 1);
 
-    sdhci_check_capareg(s, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    sdhci_check_capareg(s, errp);
+    if (*errp) {
         return;
     }
 }
@@ -1337,11 +1336,10 @@ void sdhci_uninitfn(SDHCIState *s)
 
 void sdhci_common_realize(SDHCIState *s, Error **errp)
 {
-    Error *local_err = NULL;
+    ERRP_AUTO_PROPAGATE();
 
-    sdhci_init_readonly_registers(s, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    sdhci_init_readonly_registers(s, errp);
+    if (*errp) {
         return;
     }
     s->buf_maxsz = sdhci_get_fifolen(s);
@@ -1461,13 +1459,12 @@ static void sdhci_sysbus_finalize(Object *obj)
 
 static void sdhci_sysbus_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     SDHCIState *s = SYSBUS_SDHCI(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
-    Error *local_err = NULL;
 
-    sdhci_common_realize(s, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    sdhci_common_realize(s, errp);
+    if (*errp) {
         return;
     }
 
-- 
2.21.0

[PATCH v6 06/11] pflash: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

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 '/^Parallel NOR Flash devices$/,/^$/{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>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/block/pflash_cfi01.c | 7 +++----
 hw/block/pflash_cfi02.c | 7 +++----
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index 54e6ebd385..9b12b04b65 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -700,12 +700,12 @@ static const MemoryRegionOps pflash_cfi01_ops = {
 
 static void pflash_cfi01_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     PFlashCFI01 *pfl = PFLASH_CFI01(dev);
     uint64_t total_len;
     int ret;
     uint64_t blocks_per_device, sector_len_per_device, device_len;
     int num_devices;
-    Error *local_err = NULL;
 
     if (pfl->sector_len == 0) {
         error_setg(errp, "attribute \"sector-length\" not specified or zero.");
@@ -739,9 +739,8 @@ static void pflash_cfi01_realize(DeviceState *dev, Error **errp)
         &pfl->mem, OBJECT(dev),
         &pflash_cfi01_ops,
         pfl,
-        pfl->name, total_len, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+        pfl->name, total_len, errp);
+    if (*errp) {
         return;
     }
 
diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c
index c7d92c3e79..7b33008fd5 100644
--- a/hw/block/pflash_cfi02.c
+++ b/hw/block/pflash_cfi02.c
@@ -719,9 +719,9 @@ static const MemoryRegionOps pflash_cfi02_ops = {
 
 static void pflash_cfi02_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     PFlashCFI02 *pfl = PFLASH_CFI02(dev);
     int ret;
-    Error *local_err = NULL;
 
     if (pfl->uniform_sector_len == 0 && pfl->sector_len[0] == 0) {
         error_setg(errp, "attribute \"sector-length\" not specified or zero.");
@@ -787,9 +787,8 @@ static void pflash_cfi02_realize(DeviceState *dev, Error **errp)
 
     memory_region_init_rom_device(&pfl->orig_mem, OBJECT(pfl),
                                   &pflash_cfi02_ops, pfl, pfl->name,
-                                  pfl->chip_len, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+                                  pfl->chip_len, errp);
+    if (*errp) {
         return;
     }
 
-- 
2.21.0

[PATCH v6 07/11] fw_cfg: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

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 '/^Firmware configuration (fw_cfg)$/,/^$/{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>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/nvram/fw_cfg.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 5d879c471e..4f019efcc4 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -1142,12 +1142,11 @@ static Property fw_cfg_io_properties[] = {
 
 static void fw_cfg_io_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     FWCfgIoState *s = FW_CFG_IO(dev);
-    Error *local_err = NULL;
 
-    fw_cfg_file_slots_allocate(FW_CFG(s), &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    fw_cfg_file_slots_allocate(FW_CFG(s), errp);
+    if (*errp) {
         return;
     }
 
@@ -1193,14 +1192,13 @@ static Property fw_cfg_mem_properties[] = {
 
 static void fw_cfg_mem_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     FWCfgMemState *s = FW_CFG_MEM(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
     const MemoryRegionOps *data_ops = &fw_cfg_data_mem_ops;
-    Error *local_err = NULL;
 
-    fw_cfg_file_slots_allocate(FW_CFG(s), &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    fw_cfg_file_slots_allocate(FW_CFG(s), errp);
+    if (*errp) {
         return;
     }
 
-- 
2.21.0

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

[Vladimir Sementsov-Ogievskiy]

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>
---
 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;
-- 
2.21.0

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

[Greg Kurz]

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;

[PATCH v6 09/11] TPM: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

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 '/^TPM$/,/^$/{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>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
---
 hw/tpm/tpm_util.c | 7 +++----
 tpm.c             | 7 +++----
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/hw/tpm/tpm_util.c b/hw/tpm/tpm_util.c
index 62b091f0c0..b0657bbbf2 100644
--- a/hw/tpm/tpm_util.c
+++ b/hw/tpm/tpm_util.c
@@ -47,8 +47,8 @@ static void get_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
 static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
                     Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     DeviceState *dev = DEVICE(obj);
-    Error *local_err = NULL;
     Property *prop = opaque;
     TPMBackend *s, **be = qdev_get_prop_ptr(dev, prop);
     char *str;
@@ -58,9 +58,8 @@ static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
         return;
     }
 
-    visit_type_str(v, name, &str, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    visit_type_str(v, name, &str, errp);
+    if (*errp) {
         return;
     }
 
diff --git a/tpm.c b/tpm.c
index 9c9e20bbb7..359ebb7f68 100644
--- a/tpm.c
+++ b/tpm.c
@@ -81,11 +81,11 @@ TPMBackend *qemu_find_tpm_be(const char *id)
 
 static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     const char *value;
     const char *id;
     const TPMBackendClass *be;
     TPMBackend *drv;
-    Error *local_err = NULL;
     int i;
 
     if (!QLIST_EMPTY(&tpm_backends)) {
@@ -116,9 +116,8 @@ static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, Error **errp)
     }
 
     /* validate backend specific opts */
-    qemu_opts_validate(opts, be->opts, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    qemu_opts_validate(opts, be->opts, errp);
+    if (*errp) {
         return 1;
     }
 
-- 
2.21.0

[PATCH v6 10/11] nbd: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

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 '/^Network Block Device (NBD)$/,/^$/{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>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/block/nbd.h |  1 +
 block/nbd.c         | 49 +++++++++++++++++++++------------------------
 nbd/client.c        |  5 +++++
 nbd/server.c        |  5 +++++
 4 files changed, 34 insertions(+), 26 deletions(-)

diff --git a/include/block/nbd.h b/include/block/nbd.h
index 7f46932d80..4ab8d917ed 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -360,6 +360,7 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
                            const char *desc, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
 
     if (ret < 0) {
diff --git a/block/nbd.c b/block/nbd.c
index d085554f21..9701ccf887 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -990,10 +990,10 @@ static int nbd_co_receive_cmdread_reply(BDRVNBDState *s, uint64_t handle,
                                         uint64_t offset, QEMUIOVector *qiov,
                                         int *request_ret, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NBDReplyChunkIter iter;
     NBDReply reply;
     void *payload = NULL;
-    Error *local_err = NULL;
 
     NBD_FOREACH_REPLY_CHUNK(s, iter, handle, s->info.structured_reply,
                             qiov, &reply, &payload)
@@ -1012,20 +1012,20 @@ static int nbd_co_receive_cmdread_reply(BDRVNBDState *s, uint64_t handle,
             break;
         case NBD_REPLY_TYPE_OFFSET_HOLE:
             ret = nbd_parse_offset_hole_payload(s, &reply.structured, payload,
-                                                offset, qiov, &local_err);
+                                                offset, qiov, errp);
             if (ret < 0) {
                 nbd_channel_error(s, ret);
-                nbd_iter_channel_error(&iter, ret, &local_err);
+                nbd_iter_channel_error(&iter, ret, errp);
             }
             break;
         default:
             if (!nbd_reply_type_is_error(chunk->type)) {
                 /* not allowed reply type */
                 nbd_channel_error(s, -EINVAL);
-                error_setg(&local_err,
+                error_setg(errp,
                            "Unexpected reply type: %d (%s) for CMD_READ",
                            chunk->type, nbd_reply_type_lookup(chunk->type));
-                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, errp);
             }
         }
 
@@ -1043,10 +1043,10 @@ static int nbd_co_receive_blockstatus_reply(BDRVNBDState *s,
                                             NBDExtent *extent,
                                             int *request_ret, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NBDReplyChunkIter iter;
     NBDReply reply;
     void *payload = NULL;
-    Error *local_err = NULL;
     bool received = false;
 
     assert(!extent->length);
@@ -1060,27 +1060,27 @@ static int nbd_co_receive_blockstatus_reply(BDRVNBDState *s,
         case NBD_REPLY_TYPE_BLOCK_STATUS:
             if (received) {
                 nbd_channel_error(s, -EINVAL);
-                error_setg(&local_err, "Several BLOCK_STATUS chunks in reply");
-                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
+                error_setg(errp, "Several BLOCK_STATUS chunks in reply");
+                nbd_iter_channel_error(&iter, -EINVAL, errp);
             }
             received = true;
 
             ret = nbd_parse_blockstatus_payload(s, &reply.structured,
                                                 payload, length, extent,
-                                                &local_err);
+                                                errp);
             if (ret < 0) {
                 nbd_channel_error(s, ret);
-                nbd_iter_channel_error(&iter, ret, &local_err);
+                nbd_iter_channel_error(&iter, ret, errp);
             }
             break;
         default:
             if (!nbd_reply_type_is_error(chunk->type)) {
                 nbd_channel_error(s, -EINVAL);
-                error_setg(&local_err,
+                error_setg(errp,
                            "Unexpected reply type: %d (%s) "
                            "for CMD_BLOCK_STATUS",
                            chunk->type, nbd_reply_type_lookup(chunk->type));
-                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, errp);
             }
         }
 
@@ -1089,8 +1089,8 @@ static int nbd_co_receive_blockstatus_reply(BDRVNBDState *s,
     }
 
     if (!extent->length && !iter.request_ret) {
-        error_setg(&local_err, "Server did not reply with any status extents");
-        nbd_iter_channel_error(&iter, -EIO, &local_err);
+        error_setg(errp, "Server did not reply with any status extents");
+        nbd_iter_channel_error(&iter, -EIO, errp);
     }
 
     error_propagate(errp, iter.err);
@@ -1385,16 +1385,15 @@ static void nbd_client_close(BlockDriverState *bs)
 static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
                                                   Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     QIOChannelSocket *sioc;
-    Error *local_err = NULL;
 
     sioc = qio_channel_socket_new();
     qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
 
-    qio_channel_socket_connect_sync(sioc, saddr, &local_err);
-    if (local_err) {
+    qio_channel_socket_connect_sync(sioc, saddr, errp);
+    if (*errp) {
         object_unref(OBJECT(sioc));
-        error_propagate(errp, local_err);
         return NULL;
     }
 
@@ -1698,10 +1697,10 @@ static bool nbd_process_legacy_socket_options(QDict *output_options,
 static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
                                  Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     SocketAddress *saddr = NULL;
     QDict *addr = NULL;
     Visitor *iv = NULL;
-    Error *local_err = NULL;
 
     qdict_extract_subqdict(options, &addr, "server.");
     if (!qdict_size(addr)) {
@@ -1714,9 +1713,8 @@ static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
         goto done;
     }
 
-    visit_type_SocketAddress(iv, NULL, &saddr, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    visit_type_SocketAddress(iv, NULL, &saddr, errp);
+    if (*errp) {
         goto done;
     }
 
@@ -1809,15 +1807,14 @@ static QemuOptsList nbd_runtime_opts = {
 static int nbd_process_options(BlockDriverState *bs, QDict *options,
                                Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     BDRVNBDState *s = bs->opaque;
     QemuOpts *opts;
-    Error *local_err = NULL;
     int ret = -EINVAL;
 
     opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
-    qemu_opts_absorb_qdict(opts, options, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    qemu_opts_absorb_qdict(opts, options, errp);
+    if (*errp) {
         goto error;
     }
 
diff --git a/nbd/client.c b/nbd/client.c
index ba173108ba..e258ef3f7e 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -68,6 +68,7 @@ static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt,
                                    uint32_t len, const char *data,
                                    Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NBDOption req;
     QEMU_BUILD_BUG_ON(sizeof(req) != 16);
 
@@ -153,6 +154,7 @@ static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt,
 static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply,
                                 bool strict, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     g_autofree char *msg = NULL;
 
     if (!(reply->type & (1 << 31))) {
@@ -337,6 +339,7 @@ static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
 static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt,
                               NBDExportInfo *info, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NBDOptionReply reply;
     uint32_t len = strlen(info->name);
     uint16_t type;
@@ -882,6 +885,7 @@ static int nbd_start_negotiate(AioContext *aio_context, QIOChannel *ioc,
                                bool structured_reply, bool *zeroes,
                                Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     uint64_t magic;
 
     trace_nbd_start_negotiate(tlscreds, hostname ? hostname : "<null>");
@@ -1017,6 +1021,7 @@ int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
                           const char *hostname, QIOChannel **outioc,
                           NBDExportInfo *info, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     int result;
     bool zeroes;
     bool base_allocation = info->base_allocation;
diff --git a/nbd/server.c b/nbd/server.c
index 24ebc1a805..19de61a23e 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -211,6 +211,7 @@ static int GCC_FMT_ATTR(4, 0)
 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
                             Error **errp, const char *fmt, va_list va)
 {
+    ERRP_AUTO_PROPAGATE();
     g_autofree char *msg = NULL;
     int ret;
     size_t len;
@@ -369,6 +370,7 @@ static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length,
 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
                                        Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     size_t name_len, desc_len;
     uint32_t len;
     const char *name = exp->name ? exp->name : "";
@@ -432,6 +434,7 @@ static void nbd_check_meta_export(NBDClient *client)
 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
                                             Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     g_autofree char *name = NULL;
     char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
     size_t len;
@@ -1272,6 +1275,7 @@ static int nbd_negotiate_options(NBDClient *client, Error **errp)
  */
 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
     int ret;
 
@@ -1646,6 +1650,7 @@ void nbd_export_close(NBDExport *exp)
 
 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {
         nbd_export_close(exp);
         return;
-- 
2.21.0

[PATCH v6 11/11] xen: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

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 '/^X86 Xen CPUs$/,/^$/{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>
---
 hw/block/dataplane/xen-block.c |  17 ++---
 hw/block/xen-block.c           | 125 ++++++++++++++-------------------
 hw/pci-host/xen_igd_pt.c       |   7 +-
 hw/xen/xen-backend.c           |   7 +-
 hw/xen/xen-bus.c               | 100 ++++++++++++--------------
 hw/xen/xen-host-pci-device.c   |  27 ++++---
 hw/xen/xen_pt.c                |  25 +++----
 hw/xen/xen_pt_config_init.c    |  20 +++---
 8 files changed, 142 insertions(+), 186 deletions(-)

diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c
index 3b9caeb2fa..c38e3c3d85 100644
--- a/hw/block/dataplane/xen-block.c
+++ b/hw/block/dataplane/xen-block.c
@@ -727,8 +727,8 @@ void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
                                unsigned int protocol,
                                Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenDevice *xendev = dataplane->xendev;
-    Error *local_err = NULL;
     unsigned int ring_size;
     unsigned int i;
 
@@ -764,9 +764,8 @@ void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
     }
 
     xen_device_set_max_grant_refs(xendev, dataplane->nr_ring_ref,
-                                  &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+                                  errp);
+    if (*errp) {
         goto stop;
     }
 
@@ -774,9 +773,8 @@ void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
                                               dataplane->ring_ref,
                                               dataplane->nr_ring_ref,
                                               PROT_READ | PROT_WRITE,
-                                              &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+                                              errp);
+    if (*errp) {
         goto stop;
     }
 
@@ -809,9 +807,8 @@ void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
     dataplane->event_channel =
         xen_device_bind_event_channel(xendev, dataplane->ctx, event_channel,
                                       xen_block_dataplane_event, dataplane,
-                                      &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+                                      errp);
+    if (*errp) {
         goto stop;
     }
 
diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index 879fc310a4..70428f5a79 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -194,6 +194,7 @@ static const BlockDevOps xen_block_dev_ops = {
 
 static void xen_block_realize(XenDevice *xendev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
     XenBlockDeviceClass *blockdev_class =
         XEN_BLOCK_DEVICE_GET_CLASS(xendev);
@@ -201,7 +202,6 @@ static void xen_block_realize(XenDevice *xendev, Error **errp)
     XenBlockVdev *vdev = &blockdev->props.vdev;
     BlockConf *conf = &blockdev->props.conf;
     BlockBackend *blk = conf->blk;
-    Error *local_err = NULL;
 
     if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
         error_setg(errp, "vdev property not set");
@@ -211,9 +211,8 @@ static void xen_block_realize(XenDevice *xendev, Error **errp)
     trace_xen_block_realize(type, vdev->disk, vdev->partition);
 
     if (blockdev_class->realize) {
-        blockdev_class->realize(blockdev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        blockdev_class->realize(blockdev, errp);
+        if (*errp) {
             return;
         }
     }
@@ -283,8 +282,8 @@ static void xen_block_frontend_changed(XenDevice *xendev,
                                        enum xenbus_state frontend_state,
                                        Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
-    Error *local_err = NULL;
 
     switch (frontend_state) {
     case XenbusStateInitialised:
@@ -293,15 +292,13 @@ static void xen_block_frontend_changed(XenDevice *xendev,
             break;
         }
 
-        xen_block_disconnect(xendev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xen_block_disconnect(xendev, errp);
+        if (*errp) {
             break;
         }
 
-        xen_block_connect(xendev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xen_block_connect(xendev, errp);
+        if (*errp) {
             break;
         }
 
@@ -314,9 +311,8 @@ static void xen_block_frontend_changed(XenDevice *xendev,
 
     case XenbusStateClosed:
     case XenbusStateUnknown:
-        xen_block_disconnect(xendev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xen_block_disconnect(xendev, errp);
+        if (*errp) {
             break;
         }
 
@@ -403,10 +399,10 @@ static int vbd_name_to_disk(const char *name, const char **endp,
 static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
                                void *opaque, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     DeviceState *dev = DEVICE(obj);
     Property *prop = opaque;
     XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
-    Error *local_err = NULL;
     char *str, *p;
     const char *end;
 
@@ -415,9 +411,8 @@ static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
         return;
     }
 
-    visit_type_str(v, name, &str, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    visit_type_str(v, name, &str, errp);
+    if (*errp) {
         return;
     }
 
@@ -671,9 +666,9 @@ static void xen_block_blockdev_del(const char *node_name, Error **errp)
 static char *xen_block_blockdev_add(const char *id, QDict *qdict,
                                     Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     const char *driver = qdict_get_try_str(qdict, "driver");
     BlockdevOptions *options = NULL;
-    Error *local_err = NULL;
     char *node_name;
     Visitor *v;
 
@@ -688,18 +683,16 @@ static char *xen_block_blockdev_add(const char *id, QDict *qdict,
     trace_xen_block_blockdev_add(node_name);
 
     v = qobject_input_visitor_new(QOBJECT(qdict));
-    visit_type_BlockdevOptions(v, NULL, &options, &local_err);
+    visit_type_BlockdevOptions(v, NULL, &options, errp);
     visit_free(v);
 
-    if (local_err) {
-        error_propagate(errp, local_err);
+    if (*errp) {
         goto fail;
     }
 
-    qmp_blockdev_add(options, &local_err);
+    qmp_blockdev_add(options, errp);
 
-    if (local_err) {
-        error_propagate(errp, local_err);
+    if (*errp) {
         goto fail;
     }
 
@@ -718,14 +711,12 @@ fail:
 
 static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     char *node_name = drive->node_name;
 
     if (node_name) {
-        Error *local_err = NULL;
-
-        xen_block_blockdev_del(node_name, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xen_block_blockdev_del(node_name, errp);
+        if (*errp) {
             return;
         }
         g_free(node_name);
@@ -739,6 +730,7 @@ static XenBlockDrive *xen_block_drive_create(const char *id,
                                              const char *device_type,
                                              QDict *opts, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     const char *params = qdict_get_try_str(opts, "params");
     const char *mode = qdict_get_try_str(opts, "mode");
     const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
@@ -746,7 +738,6 @@ static XenBlockDrive *xen_block_drive_create(const char *id,
     char *driver = NULL;
     char *filename = NULL;
     XenBlockDrive *drive = NULL;
-    Error *local_err = NULL;
     QDict *file_layer;
     QDict *driver_layer;
 
@@ -825,13 +816,12 @@ static XenBlockDrive *xen_block_drive_create(const char *id,
 
     g_assert(!drive->node_name);
     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
-                                              &local_err);
+                                              errp);
 
     qobject_unref(driver_layer);
 
 done:
-    if (local_err) {
-        error_propagate(errp, local_err);
+    if (*errp) {
         xen_block_drive_destroy(drive, NULL);
         return NULL;
     }
@@ -856,15 +846,13 @@ static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
 static XenBlockIOThread *xen_block_iothread_create(const char *id,
                                                    Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
-    Error *local_err = NULL;
 
     iothread->id = g_strdup(id);
 
-    qmp_object_add(TYPE_IOTHREAD, id, false, NULL, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-
+    qmp_object_add(TYPE_IOTHREAD, id, false, NULL, errp);
+    if (*errp) {
         g_free(iothread->id);
         g_free(iothread);
         return NULL;
@@ -876,6 +864,7 @@ static XenBlockIOThread *xen_block_iothread_create(const char *id,
 static void xen_block_device_create(XenBackendInstance *backend,
                                     QDict *opts, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBus *xenbus = xen_backend_get_bus(backend);
     const char *name = xen_backend_get_name(backend);
     unsigned long number;
@@ -883,7 +872,6 @@ static void xen_block_device_create(XenBackendInstance *backend,
     XenBlockDrive *drive = NULL;
     XenBlockIOThread *iothread = NULL;
     XenDevice *xendev = NULL;
-    Error *local_err = NULL;
     const char *type;
     XenBlockDevice *blockdev;
 
@@ -915,52 +903,48 @@ static void xen_block_device_create(XenBackendInstance *backend,
         goto fail;
     }
 
-    drive = xen_block_drive_create(vdev, device_type, opts, &local_err);
+    drive = xen_block_drive_create(vdev, device_type, opts, errp);
     if (!drive) {
-        error_propagate_prepend(errp, local_err, "failed to create drive: ");
+        error_prepend(errp, "failed to create drive: ");
         goto fail;
     }
 
-    iothread = xen_block_iothread_create(vdev, &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to create iothread: ");
+    iothread = xen_block_iothread_create(vdev, errp);
+    if (*errp) {
+        error_prepend(errp, "failed to create iothread: ");
         goto fail;
     }
 
     xendev = XEN_DEVICE(qdev_create(BUS(xenbus), type));
     blockdev = XEN_BLOCK_DEVICE(xendev);
 
-    object_property_set_str(OBJECT(xendev), vdev, "vdev", &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err, "failed to set 'vdev': ");
+    object_property_set_str(OBJECT(xendev), vdev, "vdev", errp);
+    if (*errp) {
+        error_prepend(errp, "failed to set 'vdev': ");
         goto fail;
     }
 
     object_property_set_str(OBJECT(xendev),
                             xen_block_drive_get_node_name(drive), "drive",
-                            &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err, "failed to set 'drive': ");
+                            errp);
+    if (*errp) {
+        error_prepend(errp, "failed to set 'drive': ");
         goto fail;
     }
 
     object_property_set_str(OBJECT(xendev), iothread->id, "iothread",
-                            &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to set 'iothread': ");
+                            errp);
+    if (*errp) {
+        error_prepend(errp, "failed to set 'iothread': ");
         goto fail;
     }
 
     blockdev->iothread = iothread;
     blockdev->drive = drive;
 
-    object_property_set_bool(OBJECT(xendev), true, "realized", &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "realization of device %s failed: ",
-                                type);
+    object_property_set_bool(OBJECT(xendev), true, "realized", errp);
+    if (*errp) {
+        error_prepend(errp, "realization of device %s failed: ", type);
         goto fail;
     }
 
@@ -984,6 +968,7 @@ fail:
 static void xen_block_device_destroy(XenBackendInstance *backend,
                                      Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenDevice *xendev = xen_backend_get_device(backend);
     XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
     XenBlockVdev *vdev = &blockdev->props.vdev;
@@ -995,23 +980,17 @@ static void xen_block_device_destroy(XenBackendInstance *backend,
     object_unparent(OBJECT(xendev));
 
     if (iothread) {
-        Error *local_err = NULL;
-
-        xen_block_iothread_destroy(iothread, &local_err);
-        if (local_err) {
-            error_propagate_prepend(errp, local_err,
-                                "failed to destroy iothread: ");
+        xen_block_iothread_destroy(iothread, errp);
+        if (*errp) {
+            error_prepend(errp, "failed to destroy iothread: ");
             return;
         }
     }
 
     if (drive) {
-        Error *local_err = NULL;
-
-        xen_block_drive_destroy(drive, &local_err);
-        if (local_err) {
-            error_propagate_prepend(errp, local_err,
-                                "failed to destroy drive: ");
+        xen_block_drive_destroy(drive, errp);
+        if (*errp) {
+            error_prepend(errp, "failed to destroy drive: ");
         }
     }
 }
diff --git a/hw/pci-host/xen_igd_pt.c b/hw/pci-host/xen_igd_pt.c
index efcc9347ff..29ade9ca25 100644
--- a/hw/pci-host/xen_igd_pt.c
+++ b/hw/pci-host/xen_igd_pt.c
@@ -79,17 +79,16 @@ static void host_pci_config_read(int pos, int len, uint32_t *val, Error **errp)
 
 static void igd_pt_i440fx_realize(PCIDevice *pci_dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     uint32_t val = 0;
     size_t i;
     int pos, len;
-    Error *local_err = NULL;
 
     for (i = 0; i < ARRAY_SIZE(igd_host_bridge_infos); i++) {
         pos = igd_host_bridge_infos[i].offset;
         len = igd_host_bridge_infos[i].len;
-        host_pci_config_read(pos, len, &val, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        host_pci_config_read(pos, len, &val, errp);
+        if (*errp) {
             return;
         }
         pci_default_write_config(pci_dev, pos, val, len);
diff --git a/hw/xen/xen-backend.c b/hw/xen/xen-backend.c
index da065f81b7..1cc0694053 100644
--- a/hw/xen/xen-backend.c
+++ b/hw/xen/xen-backend.c
@@ -98,9 +98,9 @@ static void xen_backend_list_remove(XenBackendInstance *backend)
 void xen_backend_device_create(XenBus *xenbus, const char *type,
                                const char *name, QDict *opts, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     const XenBackendImpl *impl = xen_backend_table_lookup(type);
     XenBackendInstance *backend;
-    Error *local_error = NULL;
 
     if (!impl) {
         return;
@@ -110,9 +110,8 @@ void xen_backend_device_create(XenBus *xenbus, const char *type,
     backend->xenbus = xenbus;
     backend->name = g_strdup(name);
 
-    impl->create(backend, opts, &local_error);
-    if (local_error) {
-        error_propagate(errp, local_error);
+    impl->create(backend, opts, errp);
+    if (*errp) {
         g_free(backend->name);
         g_free(backend);
         return;
diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index c2ad22a42d..270ee31aa5 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -53,9 +53,9 @@ static char *xen_device_get_frontend_path(XenDevice *xendev)
 
 static void xen_device_unplug(XenDevice *xendev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
     const char *type = object_get_typename(OBJECT(xendev));
-    Error *local_err = NULL;
     xs_transaction_t tid;
 
     trace_xen_device_unplug(type, xendev->name);
@@ -69,14 +69,14 @@ again:
     }
 
     xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "online",
-                   &local_err, "%u", 0);
-    if (local_err) {
+                   errp, "%u", 0);
+    if (*errp) {
         goto abort;
     }
 
     xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "state",
-                   &local_err, "%u", XenbusStateClosing);
-    if (local_err) {
+                   errp, "%u", XenbusStateClosing);
+    if (*errp) {
         goto abort;
     }
 
@@ -96,7 +96,6 @@ abort:
      * from ending the transaction.
      */
     xs_transaction_end(xenbus->xsh, tid, true);
-    error_propagate(errp, local_err);
 }
 
 static void xen_bus_print_dev(Monitor *mon, DeviceState *dev, int indent)
@@ -205,15 +204,13 @@ static XenWatch *watch_list_add(XenWatchList *watch_list, const char *node,
                                 const char *key, XenWatchHandler handler,
                                 void *opaque, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenWatch *watch = new_watch(node, key, handler, opaque);
-    Error *local_err = NULL;
 
     notifier_list_add(&watch_list->notifiers, &watch->notifier);
 
-    xs_node_watch(watch_list->xsh, node, key, watch->token, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-
+    xs_node_watch(watch_list->xsh, node, key, watch->token, errp);
+    if (*errp) {
         notifier_remove(&watch->notifier);
         free_watch(watch);
 
@@ -255,11 +252,11 @@ static void xen_bus_backend_create(XenBus *xenbus, const char *type,
                                    const char *name, char *path,
                                    Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     xs_transaction_t tid;
     char **key;
     QDict *opts;
     unsigned int i, n;
-    Error *local_err = NULL;
 
     trace_xen_bus_backend_create(type, path);
 
@@ -314,13 +311,11 @@ again:
         return;
     }
 
-    xen_backend_device_create(xenbus, type, name, opts, &local_err);
+    xen_backend_device_create(xenbus, type, name, opts, errp);
     qobject_unref(opts);
 
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to create '%s' device '%s': ",
-                                type, name);
+    if (*errp) {
+        error_prepend(errp, "failed to create '%s' device '%s': ", type, name);
     }
 }
 
@@ -451,9 +446,9 @@ static void xen_bus_unrealize(BusState *bus, Error **errp)
 
 static void xen_bus_realize(BusState *bus, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBus *xenbus = XEN_BUS(bus);
     unsigned int domid;
-    Error *local_err = NULL;
 
     trace_xen_bus_realize();
 
@@ -476,10 +471,10 @@ static void xen_bus_realize(BusState *bus, Error **errp)
 
     xenbus->backend_watch =
         xen_bus_add_watch(xenbus, "", /* domain root node */
-                          "backend", xen_bus_backend_changed, &local_err);
-    if (local_err) {
+                          "backend", xen_bus_backend_changed, errp);
+    if (*errp) {
         /* This need not be treated as a hard error so don't propagate */
-        error_reportf_err(local_err,
+        error_reportf_err(*errp,
                           "failed to set up enumeration watch: ");
     }
 
@@ -692,9 +687,9 @@ static void xen_device_remove_watch(XenDevice *xendev, XenWatch *watch,
 
 static void xen_device_backend_create(XenDevice *xendev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
     struct xs_permissions perms[2];
-    Error *local_err = NULL;
 
     xendev->backend_path = xen_device_get_backend_path(xendev);
 
@@ -706,30 +701,27 @@ static void xen_device_backend_create(XenDevice *xendev, Error **errp)
     g_assert(xenbus->xsh);
 
     xs_node_create(xenbus->xsh, XBT_NULL, xendev->backend_path, perms,
-                   ARRAY_SIZE(perms), &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to create backend: ");
+                   ARRAY_SIZE(perms), errp);
+    if (*errp) {
+        error_prepend(errp, "failed to create backend: ");
         return;
     }
 
     xendev->backend_state_watch =
         xen_device_add_watch(xendev, xendev->backend_path,
                              "state", xen_device_backend_changed,
-                             &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to watch backend state: ");
+                             errp);
+    if (*errp) {
+        error_prepend(errp, "failed to watch backend state: ");
         return;
     }
 
     xendev->backend_online_watch =
         xen_device_add_watch(xendev, xendev->backend_path,
                              "online", xen_device_backend_changed,
-                             &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to watch backend online: ");
+                             errp);
+    if (*errp) {
+        error_prepend(errp, "failed to watch backend online: ");
         return;
     }
 }
@@ -866,9 +858,9 @@ static bool xen_device_frontend_exists(XenDevice *xendev)
 
 static void xen_device_frontend_create(XenDevice *xendev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
     struct xs_permissions perms[2];
-    Error *local_err = NULL;
 
     xendev->frontend_path = xen_device_get_frontend_path(xendev);
 
@@ -885,20 +877,18 @@ static void xen_device_frontend_create(XenDevice *xendev, Error **errp)
         g_assert(xenbus->xsh);
 
         xs_node_create(xenbus->xsh, XBT_NULL, xendev->frontend_path, perms,
-                       ARRAY_SIZE(perms), &local_err);
-        if (local_err) {
-            error_propagate_prepend(errp, local_err,
-                                    "failed to create frontend: ");
+                       ARRAY_SIZE(perms), errp);
+        if (*errp) {
+            error_prepend(errp, "failed to create frontend: ");
             return;
         }
     }
 
     xendev->frontend_state_watch =
         xen_device_add_watch(xendev, xendev->frontend_path, "state",
-                             xen_device_frontend_changed, &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to watch frontend state: ");
+                             xen_device_frontend_changed, errp);
+    if (*errp) {
+        error_prepend(errp, "failed to watch frontend state: ");
     }
 }
 
@@ -1228,11 +1218,11 @@ static void xen_device_exit(Notifier *n, void *data)
 
 static void xen_device_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenDevice *xendev = XEN_DEVICE(dev);
     XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
     XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
     const char *type = object_get_typename(OBJECT(xendev));
-    Error *local_err = NULL;
 
     if (xendev->frontend_id == DOMID_INVALID) {
         xendev->frontend_id = xen_domid;
@@ -1248,10 +1238,9 @@ static void xen_device_realize(DeviceState *dev, Error **errp)
         goto unrealize;
     }
 
-    xendev->name = xendev_class->get_name(xendev, &local_err);
-    if (local_err) {
-        error_propagate_prepend(errp, local_err,
-                                "failed to get device name: ");
+    xendev->name = xendev_class->get_name(xendev, errp);
+    if (*errp) {
+        error_prepend(errp, "failed to get device name: ");
         goto unrealize;
     }
 
@@ -1274,22 +1263,19 @@ static void xen_device_realize(DeviceState *dev, Error **errp)
     xendev->feature_grant_copy =
         (xengnttab_grant_copy(xendev->xgth, 0, NULL) == 0);
 
-    xen_device_backend_create(xendev, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    xen_device_backend_create(xendev, errp);
+    if (*errp) {
         goto unrealize;
     }
 
-    xen_device_frontend_create(xendev, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    xen_device_frontend_create(xendev, errp);
+    if (*errp) {
         goto unrealize;
     }
 
     if (xendev_class->realize) {
-        xendev_class->realize(xendev, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        xendev_class->realize(xendev, errp);
+        if (*errp) {
             goto unrealize;
         }
     }
diff --git a/hw/xen/xen-host-pci-device.c b/hw/xen/xen-host-pci-device.c
index 1b44dcafaf..02379c341c 100644
--- a/hw/xen/xen-host-pci-device.c
+++ b/hw/xen/xen-host-pci-device.c
@@ -333,8 +333,8 @@ void xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t domain,
                              uint8_t bus, uint8_t dev, uint8_t func,
                              Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     unsigned int v;
-    Error *err = NULL;
 
     d->config_fd = -1;
     d->domain = domain;
@@ -342,36 +342,36 @@ void xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t domain,
     d->dev = dev;
     d->func = func;
 
-    xen_host_pci_config_open(d, &err);
-    if (err) {
+    xen_host_pci_config_open(d, errp);
+    if (*errp) {
         goto error;
     }
 
-    xen_host_pci_get_resource(d, &err);
-    if (err) {
+    xen_host_pci_get_resource(d, errp);
+    if (*errp) {
         goto error;
     }
 
-    xen_host_pci_get_hex_value(d, "vendor", &v, &err);
-    if (err) {
+    xen_host_pci_get_hex_value(d, "vendor", &v, errp);
+    if (*errp) {
         goto error;
     }
     d->vendor_id = v;
 
-    xen_host_pci_get_hex_value(d, "device", &v, &err);
-    if (err) {
+    xen_host_pci_get_hex_value(d, "device", &v, errp);
+    if (*errp) {
         goto error;
     }
     d->device_id = v;
 
-    xen_host_pci_get_dec_value(d, "irq", &v, &err);
-    if (err) {
+    xen_host_pci_get_dec_value(d, "irq", &v, errp);
+    if (*errp) {
         goto error;
     }
     d->irq = v;
 
-    xen_host_pci_get_hex_value(d, "class", &v, &err);
-    if (err) {
+    xen_host_pci_get_hex_value(d, "class", &v, errp);
+    if (*errp) {
         goto error;
     }
     d->class_code = v;
@@ -381,7 +381,6 @@ void xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t domain,
     return;
 
 error:
-    error_propagate(errp, err);
 
     if (d->config_fd >= 0) {
         close(d->config_fd);
diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index 9e767d4244..33b68dfcb8 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -767,12 +767,12 @@ static void xen_pt_destroy(PCIDevice *d) {
 
 static void xen_pt_realize(PCIDevice *d, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     XenPCIPassthroughState *s = XEN_PT_DEVICE(d);
     int i, rc = 0;
     uint8_t machine_irq = 0, scratch;
     uint16_t cmd = 0;
     int pirq = XEN_PT_UNASSIGNED_PIRQ;
-    Error *err = NULL;
 
     /* register real device */
     XEN_PT_LOG(d, "Assigning real physical device %02x:%02x.%d"
@@ -783,10 +783,9 @@ static void xen_pt_realize(PCIDevice *d, Error **errp)
     xen_host_pci_device_get(&s->real_device,
                             s->hostaddr.domain, s->hostaddr.bus,
                             s->hostaddr.slot, s->hostaddr.function,
-                            &err);
-    if (err) {
-        error_append_hint(&err, "Failed to \"open\" the real pci device");
-        error_propagate(errp, err);
+                            errp);
+    if (*errp) {
+        error_append_hint(errp, "Failed to \"open\" the real pci device");
         return;
     }
 
@@ -813,11 +812,10 @@ static void xen_pt_realize(PCIDevice *d, Error **errp)
             return;
         }
 
-        xen_pt_setup_vga(s, &s->real_device, &err);
-        if (err) {
-            error_append_hint(&err, "Setup VGA BIOS of passthrough"
-                    " GFX failed");
-            error_propagate(errp, err);
+        xen_pt_setup_vga(s, &s->real_device, errp);
+        if (*errp) {
+            error_append_hint(errp, "Setup VGA BIOS of passthrough"
+                              " GFX failed");
             xen_host_pci_device_put(&s->real_device);
             return;
         }
@@ -830,10 +828,9 @@ static void xen_pt_realize(PCIDevice *d, Error **errp)
     xen_pt_register_regions(s, &cmd);
 
     /* reinitialize each config register to be emulated */
-    xen_pt_config_init(s, &err);
-    if (err) {
-        error_append_hint(&err, "PCI Config space initialisation failed");
-        error_propagate(errp, err);
+    xen_pt_config_init(s, errp);
+    if (*errp) {
+        error_append_hint(errp, "PCI Config space initialisation failed");
         rc = -1;
         goto err_out;
     }
diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
index 31ec5add1d..af3fbd1bfb 100644
--- a/hw/xen/xen_pt_config_init.c
+++ b/hw/xen/xen_pt_config_init.c
@@ -2008,8 +2008,8 @@ static void xen_pt_config_reg_init(XenPCIPassthroughState *s,
 
 void xen_pt_config_init(XenPCIPassthroughState *s, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     int i, rc;
-    Error *err = NULL;
 
     QLIST_INIT(&s->reg_grps);
 
@@ -2052,10 +2052,9 @@ void xen_pt_config_init(XenPCIPassthroughState *s, Error **errp)
                                                   reg_grp_offset,
                                                   &reg_grp_entry->size);
             if (rc < 0) {
-                error_setg(&err, "Failed to initialize %d/%zu, type = 0x%x,"
+                error_setg(errp, "Failed to initialize %d/%zu, type = 0x%x,"
                            " rc: %d", i, ARRAY_SIZE(xen_pt_emu_reg_grps),
                            xen_pt_emu_reg_grps[i].grp_type, rc);
-                error_propagate(errp, err);
                 xen_pt_config_delete(s);
                 return;
             }
@@ -2068,13 +2067,14 @@ void xen_pt_config_init(XenPCIPassthroughState *s, Error **errp)
 
                 /* initialize capability register */
                 for (j = 0; regs->size != 0; j++, regs++) {
-                    xen_pt_config_reg_init(s, reg_grp_entry, regs, &err);
-                    if (err) {
-                        error_append_hint(&err, "Failed to init register %d"
-                                " offsets 0x%x in grp_type = 0x%x (%d/%zu)", j,
-                                regs->offset, xen_pt_emu_reg_grps[i].grp_type,
-                                i, ARRAY_SIZE(xen_pt_emu_reg_grps));
-                        error_propagate(errp, err);
+                    xen_pt_config_reg_init(s, reg_grp_entry, regs, errp);
+                    if (*errp) {
+                        error_append_hint(errp, "Failed to init register %d"
+                                          " offsets 0x%x in grp_type = 0x%x (%d/%zu)",
+                                          j,
+                                          regs->offset,
+                                          xen_pt_emu_reg_grps[i].grp_type,
+                                          i, ARRAY_SIZE(xen_pt_emu_reg_grps));
                         xen_pt_config_delete(s);
                         return;
                     }
-- 
2.21.0

Re: [PATCH v6 11/11] xen: introduce ERRP_AUTO_PROPAGATE

[Paul Durrant]

On Fri, 10 Jan 2020 at 19:42, 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 '/^X86 Xen CPUs$/,/^$/{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: Paul Durrant <paul@xen.org>

Re: [PATCH v6 11/11] xen: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

13.01.2020 11:57, Paul Durrant wrote:
> On Fri, 10 Jan 2020 at 19:42, 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 '/^X86 Xen CPUs$/,/^$/{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: Paul Durrant <paul@xen.org>
> 

Thanks!

-- 
Best regards,
Vladimir

Re: [Xen-devel] [PATCH v6 00/11] error: auto propagated local_err part I

[no-reply]

Patchew URL: https://patchew.org/QEMU/20200110194158.14190-1-vsementsov@virtuozzo.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Subject: [Xen-devel] [PATCH v6 00/11] error: auto propagated local_err part I
Type: series
Message-id: 20200110194158.14190-1-vsementsov@virtuozzo.com

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Switched to a new branch 'test'
fee0dd2 xen: introduce ERRP_AUTO_PROPAGATE
9074b45 nbd: introduce ERRP_AUTO_PROPAGATE
05632cb TPM: introduce ERRP_AUTO_PROPAGATE
2a019cd virtio-9p: introduce ERRP_AUTO_PROPAGATE
b4e0525 fw_cfg: introduce ERRP_AUTO_PROPAGATE
3a69800 pflash: introduce ERRP_AUTO_PROPAGATE
f4ac870 SD (Secure Card): introduce ERRP_AUTO_PROPAGATE
29fbc1d hw/sd/ssi-sd: fix error handling in ssi_sd_realize
6ebc57a scripts: add coccinelle script to use auto propagated errp
477b9ec error: auto propagated local_err
0c38914 qapi/error: add (Error **errp) cleaning APIs

=== OUTPUT BEGIN ===
1/11 Checking commit 0c389147591a (qapi/error: add (Error **errp) cleaning APIs)
2/11 Checking commit 477b9ec03898 (error: auto propagated local_err)
ERROR: Macros with multiple statements should be enclosed in a do - while loop
#138: FILE: include/qapi/error.h:428:
+#define ERRP_AUTO_PROPAGATE()                                  \
+    g_auto(ErrorPropagator) _auto_errp_prop = {.errp = errp};  \
+    errp = ((errp == NULL || *errp == error_fatal)             \
+            ? &_auto_errp_prop.local_err : errp)

total: 1 errors, 0 warnings, 102 lines checked

Patch 2/11 has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

3/11 Checking commit 6ebc57a94cf0 (scripts: add coccinelle script to use auto propagated errp)
WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#25: 
new file mode 100644

total: 0 errors, 1 warnings, 148 lines checked

Patch 3/11 has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
4/11 Checking commit 29fbc1d61eb1 (hw/sd/ssi-sd: fix error handling in ssi_sd_realize)
5/11 Checking commit f4ac87065f2c (SD (Secure Card): introduce ERRP_AUTO_PROPAGATE)
6/11 Checking commit 3a69800331a4 (pflash: introduce ERRP_AUTO_PROPAGATE)
7/11 Checking commit b4e0525d3dcf (fw_cfg: introduce ERRP_AUTO_PROPAGATE)
8/11 Checking commit 2a019cd1f992 (virtio-9p: introduce ERRP_AUTO_PROPAGATE)
9/11 Checking commit 05632cbe2d39 (TPM: introduce ERRP_AUTO_PROPAGATE)
10/11 Checking commit 9074b450cb34 (nbd: introduce ERRP_AUTO_PROPAGATE)
11/11 Checking commit fee0dd26ea0b (xen: introduce ERRP_AUTO_PROPAGATE)
=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20200110194158.14190-1-vsementsov@virtuozzo.com/testing.checkpatch/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-devel@redhat.com

Re: [PATCH v6 00/11] error: auto propagated local_err part I

[Vladimir Sementsov-Ogievskiy]

Markus, what about this? Should I respin?

10.01.2020 22:41, Vladimir Sementsov-Ogievskiy wrote:
> Hi all!
> 
> Now, when preparations from
>   [RFC v5 000/126] error: auto propagated local_err
>   https://lists.gnu.org/archive/html/qemu-devel/2019-10/msg02771.html
>   https://src.openvz.org/scm/~vsementsov/qemu.git #tag up-auto-local-err-v5
> , after some iterations, are finally merged, let's proceed with the
> rest. Sorry for a big delay on my part.
> 
> As a first step, I decided to take subsystems, each of them covered by
> one patch, which get r-b/a-b marks by maintainer of the subsystem in v5.
> 
> v6 is available at
>   https://src.openvz.org/scm/~vsementsov/qemu.git #tag up-auto-local-err-partI-v6
> 
> Changes v5->v6:
> 01: use errp name for the parameter, add assertion
> 02: add a lot of text information, drop Eric's r-b.
>      no semantic changes.
> 03: add more comments
>      skip functions with pattern error_append_.*_hint in name
>      make errp identifier, to match any name of Error ** paramter
>      some other improvements
> 04: only commit message changed,
>      keep Philippe's r-b
> 05: new, manual update for hw/sd/ssi-sd
> 06: only commit message changed,
>      keep Philippe's r-b
> 07: only commit message changed,
>      keep Philippe's r-b
> 08: local_parse_opts() changed, so patch changed in this
>      function, drop a-b mark
>      also, indentation fixed, by improvement in coccinelle script
> 09: only commit message changed,
>      keep Stefan's r-b
> 10: commit message and a bit of context changed, still seems
>      valid to keep Eric's r-b
> 11: add new hunk: hw/pci-host/xen_igd_pt.c, so, drop r-b
>      also, indentation fixed, by improvement in coccinelle script
> 
> In these series, there is no commit-per-subsystem script, each generated
> commit is generated in separate.
> 
> Still, generating commands are very similar, and looks like
> 
>      sed -n '/^<Subsystem name>$/,/^$/{s/^F: //p}' MAINTAINERS | \
>      xargs git ls-files | grep '\.[hc]$' | \
>      xargs spatch \
>          --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
>          --macro-file scripts/cocci-macro-file.h \
>          --in-place --no-show-diff --max-width 80
> 
> Note, that in each generated commit, generation command is the only
> text, indented by 8 spaces in 'git log -1' output, so, to regenerate all
> commits (for example, after rebase, or change in coccinelle script), you
> may use the following command:
> 
> git rebase -x "sh -c \"git show --pretty= --name-only | xargs git checkout HEAD^ -- ; git reset; git log -1 | grep '^        ' | sh\"" HEAD~7
> 
> Which will start automated interactive rebase for generated patches,
> which will stop if generated patch changed
> (you may do git commit --amend to apply updated generated changes).
> 
> Note:
>    git show --pretty= --name-only   - lists files, changed in HEAD
>    git log -1 | grep '^        ' | sh   - rerun generation command of HEAD
> 
> 
> Check for compilation of changed .c files
> git rebase -x "sh -c \"git show --pretty= --name-only | sed -n 's/\.c$/.o/p' | xargs make -j9\"" HEAD~7
>    
> 
> Vladimir Sementsov-Ogievskiy (11):
>    qapi/error: add (Error **errp) cleaning APIs
>    error: auto propagated local_err
>    scripts: add coccinelle script to use auto propagated errp
>    hw/sd/ssi-sd: fix error handling in ssi_sd_realize
>    SD (Secure Card): introduce ERRP_AUTO_PROPAGATE
>    pflash: introduce ERRP_AUTO_PROPAGATE
>    fw_cfg: introduce ERRP_AUTO_PROPAGATE
>    virtio-9p: introduce ERRP_AUTO_PROPAGATE
>    TPM: introduce ERRP_AUTO_PROPAGATE
>    nbd: introduce ERRP_AUTO_PROPAGATE
>    xen: introduce ERRP_AUTO_PROPAGATE
> 
>   include/block/nbd.h                           |   1 +
>   include/qapi/error.h                          | 113 +++++++++++++-
>   block/nbd.c                                   |  49 +++---
>   hw/9pfs/9p-local.c                            |  12 +-
>   hw/9pfs/9p.c                                  |   1 +
>   hw/block/dataplane/xen-block.c                |  17 +--
>   hw/block/pflash_cfi01.c                       |   7 +-
>   hw/block/pflash_cfi02.c                       |   7 +-
>   hw/block/xen-block.c                          | 125 +++++++---------
>   hw/nvram/fw_cfg.c                             |  14 +-
>   hw/pci-host/xen_igd_pt.c                      |   7 +-
>   hw/sd/sdhci-pci.c                             |   7 +-
>   hw/sd/sdhci.c                                 |  21 ++-
>   hw/sd/ssi-sd.c                                |  26 +++-
>   hw/tpm/tpm_util.c                             |   7 +-
>   hw/xen/xen-backend.c                          |   7 +-
>   hw/xen/xen-bus.c                              | 100 ++++++-------
>   hw/xen/xen-host-pci-device.c                  |  27 ++--
>   hw/xen/xen_pt.c                               |  25 ++--
>   hw/xen/xen_pt_config_init.c                   |  20 +--
>   nbd/client.c                                  |   5 +
>   nbd/server.c                                  |   5 +
>   tpm.c                                         |   7 +-
>   scripts/coccinelle/auto-propagated-errp.cocci | 139 ++++++++++++++++++
>   24 files changed, 482 insertions(+), 267 deletions(-)
>   create mode 100644 scripts/coccinelle/auto-propagated-errp.cocci
> 
> CC: Cornelia Huck <cohuck@redhat.com>
> CC: Eric Blake <eblake@redhat.com>
> CC: Kevin Wolf <kwolf@redhat.com>
> CC: Max Reitz <mreitz@redhat.com>
> CC: Greg Kurz <groug@kaod.org>
> CC: Stefan Hajnoczi <stefanha@redhat.com>
> CC: Stefano Stabellini <sstabellini@kernel.org>
> CC: Anthony Perard <anthony.perard@citrix.com>
> CC: Paul Durrant <paul@xen.org>
> CC: "Philippe Mathieu-Daudé" <philmd@redhat.com>
> CC: Laszlo Ersek <lersek@redhat.com>
> CC: Gerd Hoffmann <kraxel@redhat.com>
> CC: Stefan Berger <stefanb@linux.ibm.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Michael Roth <mdroth@linux.vnet.ibm.com>
> CC: qemu-block@nongnu.org
> CC: xen-devel@lists.xenproject.org
> 


-- 
Best regards,
Vladimir

Re: [PATCH v6 00/11] error: auto propagated local_err part I

[Markus Armbruster]

Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> writes:

> Markus, what about this? Should I respin?

I still haven't looked at this, must be frustrating for you, sorry!
I've been under water ever since my Christmas vacation...  If you rather
want me to look at a v7 that addresses the review comments from others,
then go ahead and respin.