| Message ID | 1453219845-30939-34-git-send-email-eblake@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Eric Blake <eblake@redhat.com> writes: > As mentioned in previous patches, we want to call visit_end_struct() > functions unconditionally, so that visitors can release resources > tied up since the matching visit_start_struct() without also having > to worry about error priority if more than one error occurs. > > Even though error_propagate() can be safely used to ignore a second > error during cleanup caused by a first error, it is simpler if the > cleanup cannot set an error, and we instead split the task of > checking that an input visitor has no unvisited input as a new > function visit_check_struct(), called only if all prior steps are > successful. > > Generated code has diffs resembling: > > |@@ -59,10 +59,12 @@ void visit_type_ACPIOSTInfo(Visitor *v, > | goto out_obj; > | } > | visit_type_ACPIOSTInfo_fields(v, obj, &err); > |+ if (err) { > |+ goto out_obj; > |+ } > |+ visit_check_struct(v, &err); > | out_obj: > |- error_propagate(errp, err); > |- err = NULL; > |- visit_end_struct(v, &err); > |+ visit_end_struct(v); > | out: Basically, split visit_end_struct() into a part that runs only when there have been no errors and a part that runs as before, i.e. when visit_start_struct() succeeded, even when there have been errors since. This second part cannot fail, which simplifies error handling a bit. To review: skipping the first part when there have been errors is safe. > > Signed-off-by: Eric Blake <eblake@redhat.com> > > --- > v9: rebase to earlier changes, drop Marc-Andre's R-b > v8: rebase to 'name' motion > v7: rebase to earlier changes > v6: new patch, revised version of RFC based on discussion of v5 7/46 > --- > hmp.c | 7 ++++--- > hw/ppc/spapr_drc.c | 3 ++- > hw/virtio/virtio-balloon.c | 12 ++++++------ > include/qapi/visitor-impl.h | 4 +++- > include/qapi/visitor.h | 13 ++++++++++--- > qapi/opts-visitor.c | 17 +++++++++++++++-- > qapi/qapi-dealloc-visitor.c | 2 +- > qapi/qapi-visit-core.c | 11 +++++++++-- > qapi/qmp-input-visitor.c | 34 +++++++++++++++++++--------------- > qapi/qmp-output-visitor.c | 2 +- > qom/object.c | 5 ++--- > scripts/qapi-event.py | 3 ++- > scripts/qapi-visit.py | 9 ++++----- > tests/test-qmp-input-visitor.c | 3 ++- > vl.c | 11 +++++------ > 15 files changed, 85 insertions(+), 51 deletions(-) > > diff --git a/hmp.c b/hmp.c > index a4b74df..245617d 100644 > --- a/hmp.c > +++ b/hmp.c > @@ -1687,13 +1687,14 @@ void hmp_object_add(Monitor *mon, const QDict *qdict) > } > > object_add(type, id, pdict, v, &err); > - > -out_end: > - visit_end_struct(v, &err_end); > + visit_check_struct(v, &err_end); > if (!err && err_end) { > qmp_object_del(id, NULL); > } > error_propagate(&err, err_end); > + > +out_end: > + visit_end_struct(v); > out_clean: > opts_visitor_cleanup(ov); > > diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c > index 831ce23..3b27caa 100644 > --- a/hw/ppc/spapr_drc.c > +++ b/hw/ppc/spapr_drc.c > @@ -287,11 +287,12 @@ static void prop_get_fdt(Object *obj, Visitor *v, const char *name, > case FDT_END_NODE: > /* shouldn't ever see an FDT_END_NODE before FDT_BEGIN_NODE */ > g_assert(fdt_depth > 0); > - visit_end_struct(v, &err); > + visit_check_struct(v, &err); > if (err) { > error_propagate(errp, err); > return; > } > + visit_end_struct(v); > fdt_depth--; > break; > case FDT_PROP: { No longer calls visit_end_struct() when visit_end_struct() fails. Contradicts the rule to always call it after visit_start_struct() succeded. > diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > index 24ecd87..cefd43f 100644 > --- a/hw/virtio/virtio-balloon.c > +++ b/hw/virtio/virtio-balloon.c > @@ -136,15 +136,15 @@ static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name, > goto out_nested; > } > } > + visit_check_struct(v, &err); > out_nested: > - error_propagate(errp, err); > - err = NULL; > - visit_end_struct(v, &err); > + visit_end_struct(v); > > + if (!err) { > + visit_check_struct(v, &err); > + } > out_end: > - error_propagate(errp, err); > - err = NULL; > - visit_end_struct(v, &err); > + visit_end_struct(v); > out: > error_propagate(errp, err); > } > diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h > index 3b68b7b..248b1e5 100644 > --- a/include/qapi/visitor-impl.h > +++ b/include/qapi/visitor-impl.h > @@ -28,8 +28,10 @@ struct Visitor > * currently visit structs). */ > void (*start_struct)(Visitor *v, const char *name, void **obj, > size_t size, Error **errp); > + /* May be NULL; most useful for input visitors. */ > + void (*check_struct)(Visitor *v, Error **errp); Well, "most useful" is certainly correct since other visitors have had no use for it so far :) "intended for input visitors"? > /* Must be provided if start_struct is present. */ > - void (*end_struct)(Visitor *v, Error **errp); > + void (*end_struct)(Visitor *v); > > /* May be NULL; most useful for input visitors. */ > void (*start_implicit_struct)(Visitor *v, void **obj, size_t size, > diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h > index d7a0110..e5dcde4 100644 > --- a/include/qapi/visitor.h > +++ b/include/qapi/visitor.h > @@ -68,12 +68,19 @@ typedef struct GenericList > void visit_start_struct(Visitor *v, const char *name, void **obj, > size_t size, Error **errp); > /** > + * Prepare for completing a struct visit. > + * Should be called prior to visit_end_struct() if all other intermediate > + * visit steps were successful, to allow the caller one last chance to > + * report errors such as remaining data that was not consumed by the visit. > + */ > +void visit_check_struct(Visitor *v, Error **errp); > +/** > * Complete a struct visit started earlier. > * Must be called after any successful use of visit_start_struct(), > * even if intermediate processing was skipped due to errors, to allow > * the backend to release any resources. > */ > -void visit_end_struct(Visitor *v, Error **errp); > +void visit_end_struct(Visitor *v); > > /** > * Prepare to visit an implicit struct. > @@ -96,8 +103,8 @@ void visit_start_implicit_struct(Visitor *v, void **obj, size_t size, > * Must be called after any successful use of visit_start_implicit_struct(), > * even if intermediate processing was skipped due to errors, to allow > * the backend to release any resources. Unlike visit_end_struct(), this > - * does not need to check for errors (detection of unused keys is only > - * possible for the overall struct, not a subset). > + * does not need a counterpart function to check for errors (detection of > + * unused keys is only possible for the overall struct, not a subset). > */ > void visit_end_implicit_struct(Visitor *v); > > diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c > index df312e6..b469573 100644 > --- a/qapi/opts-visitor.c > +++ b/qapi/opts-visitor.c > @@ -157,13 +157,13 @@ opts_start_struct(Visitor *v, const char *name, void **obj, > > > static void > -opts_end_struct(Visitor *v, Error **errp) > +opts_check_struct(Visitor *v, Error **errp) > { > OptsVisitor *ov = to_ov(v); > GHashTableIter iter; > GQueue *any; > > - if (--ov->depth > 0) { > + if (ov->depth > 0) { > return; > } > Not fully visible in this diff: this function's only possible side effect is setting an error. Therefore, skipping this when there have been errors is safe. > @@ -175,6 +175,18 @@ opts_end_struct(Visitor *v, Error **errp) > first = g_queue_peek_head(any); > error_setg(errp, QERR_INVALID_PARAMETER, first->name); > } > +} > + > + > +static void > +opts_end_struct(Visitor *v) > +{ > + OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v); > + > + if (--ov->depth > 0) { > + return; > + } > + > g_hash_table_destroy(ov->unprocessed_opts); > ov->unprocessed_opts = NULL; > if (ov->fake_id_opt) { > @@ -506,6 +518,7 @@ opts_visitor_new(const QemuOpts *opts) > ov = g_malloc0(sizeof *ov); > > ov->visitor.start_struct = &opts_start_struct; > + ov->visitor.check_struct = &opts_check_struct; > ov->visitor.end_struct = &opts_end_struct; > > ov->visitor.start_list = &opts_start_list; > diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c > index 1a54864..a89e6d1 100644 > --- a/qapi/qapi-dealloc-visitor.c > +++ b/qapi/qapi-dealloc-visitor.c > @@ -65,7 +65,7 @@ static void qapi_dealloc_start_struct(Visitor *v, const char *name, void **obj, > qapi_dealloc_push(qov, obj); > } > > -static void qapi_dealloc_end_struct(Visitor *v, Error **errp) > +static void qapi_dealloc_end_struct(Visitor *v) > { > QapiDeallocVisitor *qov = to_qov(v); > void **obj = qapi_dealloc_pop(qov); > diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c > index 3360cdf..9506a02 100644 > --- a/qapi/qapi-visit-core.c > +++ b/qapi/qapi-visit-core.c > @@ -36,9 +36,16 @@ void visit_start_struct(Visitor *v, const char *name, void **obj, > v->start_struct(v, name, obj, size, errp); > } > > -void visit_end_struct(Visitor *v, Error **errp) > +void visit_check_struct(Visitor *v, Error **errp) > { > - v->end_struct(v, errp); > + if (v->check_struct) { > + v->check_struct(v, errp); > + } > +} > + > +void visit_end_struct(Visitor *v) > +{ > + v->end_struct(v); > } > > void visit_start_implicit_struct(Visitor *v, void **obj, size_t size, > diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c > index 91ef945..f256d9e 100644 > --- a/qapi/qmp-input-visitor.c > +++ b/qapi/qmp-input-visitor.c > @@ -89,8 +89,10 @@ static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp) > } > > > -static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp) > +static void qmp_input_check_struct(Visitor *v, Error **errp) > { > + QmpInputVisitor *qiv = to_qiv(v); > + > assert(qiv->nb_stack > 0); > > if (qiv->strict) { Same argument as for opts_check_struct(). > @@ -103,6 +105,19 @@ static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp) > if (g_hash_table_iter_next(&iter, (void **)&key, NULL)) { > error_setg(errp, QERR_QMP_EXTRA_MEMBER, key); > } > + } > + } > +} > + > +static void qmp_input_pop(Visitor *v) > +{ > + QmpInputVisitor *qiv = to_qiv(v); > + > + assert(qiv->nb_stack > 0); > + > + if (qiv->strict) { > + GHashTable * const top_ht = qiv->stack[qiv->nb_stack - 1].h; > + if (top_ht) { > g_hash_table_unref(top_ht); > } > } > @@ -134,12 +149,6 @@ static void qmp_input_start_struct(Visitor *v, const char *name, void **obj, > } > } > > -static void qmp_input_end_struct(Visitor *v, Error **errp) > -{ > - QmpInputVisitor *qiv = to_qiv(v); > - > - qmp_input_pop(qiv, errp); > -} Order is now funny: the end_struct() method preceeds the start_struct() method. I guess that's okay. > > static void qmp_input_start_implicit_struct(Visitor *v, void **obj, > size_t size, Error **errp) > @@ -193,12 +202,6 @@ static GenericList *qmp_input_next_list(Visitor *v, GenericList **list, > return entry; > } > > -static void qmp_input_end_list(Visitor *v) > -{ > - QmpInputVisitor *qiv = to_qiv(v); > - > - qmp_input_pop(qiv, &error_abort); > -} Likewise. > > static void qmp_input_get_next_type(Visitor *v, const char *name, QType *type, > bool promote_int, Error **errp) > @@ -355,11 +358,12 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj) > v = g_malloc0(sizeof(*v)); > > v->visitor.start_struct = qmp_input_start_struct; > - v->visitor.end_struct = qmp_input_end_struct; > + v->visitor.check_struct = qmp_input_check_struct; > + v->visitor.end_struct = qmp_input_pop; > v->visitor.start_implicit_struct = qmp_input_start_implicit_struct; > v->visitor.start_list = qmp_input_start_list; > v->visitor.next_list = qmp_input_next_list; > - v->visitor.end_list = qmp_input_end_list; > + v->visitor.end_list = qmp_input_pop; > v->visitor.type_enum = input_type_enum; > v->visitor.type_int64 = qmp_input_type_int64; > v->visitor.type_uint64 = qmp_input_type_uint64; > diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c > index 2eb200d..5376948 100644 > --- a/qapi/qmp-output-visitor.c > +++ b/qapi/qmp-output-visitor.c > @@ -116,7 +116,7 @@ static void qmp_output_start_struct(Visitor *v, const char *name, void **obj, > qmp_output_push(qov, dict); > } > > -static void qmp_output_end_struct(Visitor *v, Error **errp) > +static void qmp_output_end_struct(Visitor *v) > { > QmpOutputVisitor *qov = to_qov(v); > qmp_output_pop(qov, QTYPE_QDICT); > diff --git a/qom/object.c b/qom/object.c > index e5b0566..4644cbd 100644 > --- a/qom/object.c > +++ b/qom/object.c > @@ -2034,10 +2034,9 @@ static void property_get_tm(Object *obj, Visitor *v, const char *name, > if (err) { > goto out_end; > } > + visit_check_struct(v, &err); > out_end: > - error_propagate(errp, err); > - err = NULL; > - visit_end_struct(v, errp); > + visit_end_struct(v); > out: > error_propagate(errp, err); > > diff --git a/scripts/qapi-event.py b/scripts/qapi-event.py > index cc55de7..dea45c4 100644 > --- a/scripts/qapi-event.py > +++ b/scripts/qapi-event.py > @@ -71,8 +71,9 @@ def gen_event_send(name, arg_type): > ret += gen_visit_fields(arg_type.members, need_cast=True, > label='out_obj') > ret += mcgen(''' > + visit_check_struct(v, &err); > out_obj: > - visit_end_struct(v, &err); > + visit_end_struct(v); > if (err) { > goto out; > } > diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py > index 7a44c13..8039b97 100644 > --- a/scripts/qapi-visit.py > +++ b/scripts/qapi-visit.py > @@ -255,8 +255,7 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error > visit_type_%(c_name)s_fields(v, %(cast)sobj, &err); > ''', > c_name=type_name, cast=cast) > - if variants: > - ret += gen_err_check(label='out_obj') > + ret += gen_err_check(label='out_obj') Can't immediately see why we need this change. Care to explain? > > if variants: > ret += mcgen(''' > @@ -293,12 +292,12 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error > abort(); > } > ''') > + ret += gen_err_check(label='out_obj') Yes, because we need to skip... > > ret += mcgen(''' > + visit_check_struct(v, &err); ... this one. > out_obj: > - error_propagate(errp, err); > - err = NULL; > - visit_end_struct(v, &err); > + visit_end_struct(v); > out: > error_propagate(errp, err); > } > diff --git a/tests/test-qmp-input-visitor.c b/tests/test-qmp-input-visitor.c > index 6489e4a..cd5e765 100644 > --- a/tests/test-qmp-input-visitor.c > +++ b/tests/test-qmp-input-visitor.c > @@ -290,7 +290,8 @@ static void test_visitor_in_null(TestInputVisitorData *data, > v = visitor_input_test_init(data, "{ 'a': null }"); > visit_start_struct(v, NULL, NULL, 0, &error_abort); > visit_type_null(v, "a", &error_abort); > - visit_end_struct(v, &error_abort); > + visit_check_struct(v, &error_abort); > + visit_end_struct(v); > > /* Check that qnull reference counting is sane: > * 1 for global use, 1 for our qnull() use, and 1 still owned by 'v' > diff --git a/vl.c b/vl.c > index 22062b5..00c92b8 100644 > --- a/vl.c > +++ b/vl.c > @@ -2842,11 +2842,10 @@ static int object_create(void *opaque, QemuOpts *opts, Error **errp) > qdict_del(pdict, "qom-type"); > visit_type_str(v, "qom-type", &type, &err); > if (err) { > - goto out; > + goto out_end; Before: visit_end_struct() not called. After: visit_end_struct() called. Shouldn't this be fixed in PATCH 05? > } > if (!type_predicate(type)) { > - visit_end_struct(v, NULL); > - goto out; > + goto out_end; > } > > qdict_del(pdict, "id"); > @@ -2856,14 +2855,14 @@ static int object_create(void *opaque, QemuOpts *opts, Error **errp) > } > > object_add(type, id, pdict, v, &err); > - > -out_end: > - visit_end_struct(v, &err_end); > + visit_check_struct(v, &err_end); > if (!err && err_end) { > qmp_object_del(id, NULL); > } > error_propagate(&err, err_end); > > +out_end: > + visit_end_struct(v); > out: > opts_visitor_cleanup(ov);
diff --git a/hmp.c b/hmp.c index a4b74df..245617d 100644 --- a/hmp.c +++ b/hmp.c @@ -1687,13 +1687,14 @@ void hmp_object_add(Monitor *mon, const QDict *qdict) } object_add(type, id, pdict, v, &err); - -out_end: - visit_end_struct(v, &err_end); + visit_check_struct(v, &err_end); if (!err && err_end) { qmp_object_del(id, NULL); } error_propagate(&err, err_end); + +out_end: + visit_end_struct(v); out_clean: opts_visitor_cleanup(ov); diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c index 831ce23..3b27caa 100644 --- a/hw/ppc/spapr_drc.c +++ b/hw/ppc/spapr_drc.c @@ -287,11 +287,12 @@ static void prop_get_fdt(Object *obj, Visitor *v, const char *name, case FDT_END_NODE: /* shouldn't ever see an FDT_END_NODE before FDT_BEGIN_NODE */ g_assert(fdt_depth > 0); - visit_end_struct(v, &err); + visit_check_struct(v, &err); if (err) { error_propagate(errp, err); return; } + visit_end_struct(v); fdt_depth--; break; case FDT_PROP: { diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 24ecd87..cefd43f 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -136,15 +136,15 @@ static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name, goto out_nested; } } + visit_check_struct(v, &err); out_nested: - error_propagate(errp, err); - err = NULL; - visit_end_struct(v, &err); + visit_end_struct(v); + if (!err) { + visit_check_struct(v, &err); + } out_end: - error_propagate(errp, err); - err = NULL; - visit_end_struct(v, &err); + visit_end_struct(v); out: error_propagate(errp, err); } diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h index 3b68b7b..248b1e5 100644 --- a/include/qapi/visitor-impl.h +++ b/include/qapi/visitor-impl.h @@ -28,8 +28,10 @@ struct Visitor * currently visit structs). */ void (*start_struct)(Visitor *v, const char *name, void **obj, size_t size, Error **errp); + /* May be NULL; most useful for input visitors. */ + void (*check_struct)(Visitor *v, Error **errp); /* Must be provided if start_struct is present. */ - void (*end_struct)(Visitor *v, Error **errp); + void (*end_struct)(Visitor *v); /* May be NULL; most useful for input visitors. */ void (*start_implicit_struct)(Visitor *v, void **obj, size_t size, diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h index d7a0110..e5dcde4 100644 --- a/include/qapi/visitor.h +++ b/include/qapi/visitor.h @@ -68,12 +68,19 @@ typedef struct GenericList void visit_start_struct(Visitor *v, const char *name, void **obj, size_t size, Error **errp); /** + * Prepare for completing a struct visit. + * Should be called prior to visit_end_struct() if all other intermediate + * visit steps were successful, to allow the caller one last chance to + * report errors such as remaining data that was not consumed by the visit. + */ +void visit_check_struct(Visitor *v, Error **errp); +/** * Complete a struct visit started earlier. * Must be called after any successful use of visit_start_struct(), * even if intermediate processing was skipped due to errors, to allow * the backend to release any resources. */ -void visit_end_struct(Visitor *v, Error **errp); +void visit_end_struct(Visitor *v); /** * Prepare to visit an implicit struct. @@ -96,8 +103,8 @@ void visit_start_implicit_struct(Visitor *v, void **obj, size_t size, * Must be called after any successful use of visit_start_implicit_struct(), * even if intermediate processing was skipped due to errors, to allow * the backend to release any resources. Unlike visit_end_struct(), this - * does not need to check for errors (detection of unused keys is only - * possible for the overall struct, not a subset). + * does not need a counterpart function to check for errors (detection of + * unused keys is only possible for the overall struct, not a subset). */ void visit_end_implicit_struct(Visitor *v); diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c index df312e6..b469573 100644 --- a/qapi/opts-visitor.c +++ b/qapi/opts-visitor.c @@ -157,13 +157,13 @@ opts_start_struct(Visitor *v, const char *name, void **obj, static void -opts_end_struct(Visitor *v, Error **errp) +opts_check_struct(Visitor *v, Error **errp) { OptsVisitor *ov = to_ov(v); GHashTableIter iter; GQueue *any; - if (--ov->depth > 0) { + if (ov->depth > 0) { return; } @@ -175,6 +175,18 @@ opts_end_struct(Visitor *v, Error **errp) first = g_queue_peek_head(any); error_setg(errp, QERR_INVALID_PARAMETER, first->name); } +} + + +static void +opts_end_struct(Visitor *v) +{ + OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v); + + if (--ov->depth > 0) { + return; + } + g_hash_table_destroy(ov->unprocessed_opts); ov->unprocessed_opts = NULL; if (ov->fake_id_opt) { @@ -506,6 +518,7 @@ opts_visitor_new(const QemuOpts *opts) ov = g_malloc0(sizeof *ov); ov->visitor.start_struct = &opts_start_struct; + ov->visitor.check_struct = &opts_check_struct; ov->visitor.end_struct = &opts_end_struct; ov->visitor.start_list = &opts_start_list; diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c index 1a54864..a89e6d1 100644 --- a/qapi/qapi-dealloc-visitor.c +++ b/qapi/qapi-dealloc-visitor.c @@ -65,7 +65,7 @@ static void qapi_dealloc_start_struct(Visitor *v, const char *name, void **obj, qapi_dealloc_push(qov, obj); } -static void qapi_dealloc_end_struct(Visitor *v, Error **errp) +static void qapi_dealloc_end_struct(Visitor *v) { QapiDeallocVisitor *qov = to_qov(v); void **obj = qapi_dealloc_pop(qov); diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c index 3360cdf..9506a02 100644 --- a/qapi/qapi-visit-core.c +++ b/qapi/qapi-visit-core.c @@ -36,9 +36,16 @@ void visit_start_struct(Visitor *v, const char *name, void **obj, v->start_struct(v, name, obj, size, errp); } -void visit_end_struct(Visitor *v, Error **errp) +void visit_check_struct(Visitor *v, Error **errp) { - v->end_struct(v, errp); + if (v->check_struct) { + v->check_struct(v, errp); + } +} + +void visit_end_struct(Visitor *v) +{ + v->end_struct(v); } void visit_start_implicit_struct(Visitor *v, void **obj, size_t size, diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c index 91ef945..f256d9e 100644 --- a/qapi/qmp-input-visitor.c +++ b/qapi/qmp-input-visitor.c @@ -89,8 +89,10 @@ static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp) } -static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp) +static void qmp_input_check_struct(Visitor *v, Error **errp) { + QmpInputVisitor *qiv = to_qiv(v); + assert(qiv->nb_stack > 0); if (qiv->strict) { @@ -103,6 +105,19 @@ static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp) if (g_hash_table_iter_next(&iter, (void **)&key, NULL)) { error_setg(errp, QERR_QMP_EXTRA_MEMBER, key); } + } + } +} + +static void qmp_input_pop(Visitor *v) +{ + QmpInputVisitor *qiv = to_qiv(v); + + assert(qiv->nb_stack > 0); + + if (qiv->strict) { + GHashTable * const top_ht = qiv->stack[qiv->nb_stack - 1].h; + if (top_ht) { g_hash_table_unref(top_ht); } } @@ -134,12 +149,6 @@ static void qmp_input_start_struct(Visitor *v, const char *name, void **obj, } } -static void qmp_input_end_struct(Visitor *v, Error **errp) -{ - QmpInputVisitor *qiv = to_qiv(v); - - qmp_input_pop(qiv, errp); -} static void qmp_input_start_implicit_struct(Visitor *v, void **obj, size_t size, Error **errp) @@ -193,12 +202,6 @@ static GenericList *qmp_input_next_list(Visitor *v, GenericList **list, return entry; } -static void qmp_input_end_list(Visitor *v) -{ - QmpInputVisitor *qiv = to_qiv(v); - - qmp_input_pop(qiv, &error_abort); -} static void qmp_input_get_next_type(Visitor *v, const char *name, QType *type, bool promote_int, Error **errp) @@ -355,11 +358,12 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj) v = g_malloc0(sizeof(*v)); v->visitor.start_struct = qmp_input_start_struct; - v->visitor.end_struct = qmp_input_end_struct; + v->visitor.check_struct = qmp_input_check_struct; + v->visitor.end_struct = qmp_input_pop; v->visitor.start_implicit_struct = qmp_input_start_implicit_struct; v->visitor.start_list = qmp_input_start_list; v->visitor.next_list = qmp_input_next_list; - v->visitor.end_list = qmp_input_end_list; + v->visitor.end_list = qmp_input_pop; v->visitor.type_enum = input_type_enum; v->visitor.type_int64 = qmp_input_type_int64; v->visitor.type_uint64 = qmp_input_type_uint64; diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c index 2eb200d..5376948 100644 --- a/qapi/qmp-output-visitor.c +++ b/qapi/qmp-output-visitor.c @@ -116,7 +116,7 @@ static void qmp_output_start_struct(Visitor *v, const char *name, void **obj, qmp_output_push(qov, dict); } -static void qmp_output_end_struct(Visitor *v, Error **errp) +static void qmp_output_end_struct(Visitor *v) { QmpOutputVisitor *qov = to_qov(v); qmp_output_pop(qov, QTYPE_QDICT); diff --git a/qom/object.c b/qom/object.c index e5b0566..4644cbd 100644 --- a/qom/object.c +++ b/qom/object.c @@ -2034,10 +2034,9 @@ static void property_get_tm(Object *obj, Visitor *v, const char *name, if (err) { goto out_end; } + visit_check_struct(v, &err); out_end: - error_propagate(errp, err); - err = NULL; - visit_end_struct(v, errp); + visit_end_struct(v); out: error_propagate(errp, err); diff --git a/scripts/qapi-event.py b/scripts/qapi-event.py index cc55de7..dea45c4 100644 --- a/scripts/qapi-event.py +++ b/scripts/qapi-event.py @@ -71,8 +71,9 @@ def gen_event_send(name, arg_type): ret += gen_visit_fields(arg_type.members, need_cast=True, label='out_obj') ret += mcgen(''' + visit_check_struct(v, &err); out_obj: - visit_end_struct(v, &err); + visit_end_struct(v); if (err) { goto out; } diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py index 7a44c13..8039b97 100644 --- a/scripts/qapi-visit.py +++ b/scripts/qapi-visit.py @@ -255,8 +255,7 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error visit_type_%(c_name)s_fields(v, %(cast)sobj, &err); ''', c_name=type_name, cast=cast) - if variants: - ret += gen_err_check(label='out_obj') + ret += gen_err_check(label='out_obj') if variants: ret += mcgen(''' @@ -293,12 +292,12 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error abort(); } ''') + ret += gen_err_check(label='out_obj') ret += mcgen(''' + visit_check_struct(v, &err); out_obj: - error_propagate(errp, err); - err = NULL; - visit_end_struct(v, &err); + visit_end_struct(v); out: error_propagate(errp, err); } diff --git a/tests/test-qmp-input-visitor.c b/tests/test-qmp-input-visitor.c index 6489e4a..cd5e765 100644 --- a/tests/test-qmp-input-visitor.c +++ b/tests/test-qmp-input-visitor.c @@ -290,7 +290,8 @@ static void test_visitor_in_null(TestInputVisitorData *data, v = visitor_input_test_init(data, "{ 'a': null }"); visit_start_struct(v, NULL, NULL, 0, &error_abort); visit_type_null(v, "a", &error_abort); - visit_end_struct(v, &error_abort); + visit_check_struct(v, &error_abort); + visit_end_struct(v); /* Check that qnull reference counting is sane: * 1 for global use, 1 for our qnull() use, and 1 still owned by 'v' diff --git a/vl.c b/vl.c index 22062b5..00c92b8 100644 --- a/vl.c +++ b/vl.c @@ -2842,11 +2842,10 @@ static int object_create(void *opaque, QemuOpts *opts, Error **errp) qdict_del(pdict, "qom-type"); visit_type_str(v, "qom-type", &type, &err); if (err) { - goto out; + goto out_end; } if (!type_predicate(type)) { - visit_end_struct(v, NULL); - goto out; + goto out_end; } qdict_del(pdict, "id"); @@ -2856,14 +2855,14 @@ static int object_create(void *opaque, QemuOpts *opts, Error **errp) } object_add(type, id, pdict, v, &err); - -out_end: - visit_end_struct(v, &err_end); + visit_check_struct(v, &err_end); if (!err && err_end) { qmp_object_del(id, NULL); } error_propagate(&err, err_end); +out_end: + visit_end_struct(v); out: opts_visitor_cleanup(ov);
As mentioned in previous patches, we want to call visit_end_struct() functions unconditionally, so that visitors can release resources tied up since the matching visit_start_struct() without also having to worry about error priority if more than one error occurs. Even though error_propagate() can be safely used to ignore a second error during cleanup caused by a first error, it is simpler if the cleanup cannot set an error, and we instead split the task of checking that an input visitor has no unvisited input as a new function visit_check_struct(), called only if all prior steps are successful. Generated code has diffs resembling: |@@ -59,10 +59,12 @@ void visit_type_ACPIOSTInfo(Visitor *v, | goto out_obj; | } | visit_type_ACPIOSTInfo_fields(v, obj, &err); |+ if (err) { |+ goto out_obj; |+ } |+ visit_check_struct(v, &err); | out_obj: |- error_propagate(errp, err); |- err = NULL; |- visit_end_struct(v, &err); |+ visit_end_struct(v); | out: Signed-off-by: Eric Blake <eblake@redhat.com> --- v9: rebase to earlier changes, drop Marc-Andre's R-b v8: rebase to 'name' motion v7: rebase to earlier changes v6: new patch, revised version of RFC based on discussion of v5 7/46 --- hmp.c | 7 ++++--- hw/ppc/spapr_drc.c | 3 ++- hw/virtio/virtio-balloon.c | 12 ++++++------ include/qapi/visitor-impl.h | 4 +++- include/qapi/visitor.h | 13 ++++++++++--- qapi/opts-visitor.c | 17 +++++++++++++++-- qapi/qapi-dealloc-visitor.c | 2 +- qapi/qapi-visit-core.c | 11 +++++++++-- qapi/qmp-input-visitor.c | 34 +++++++++++++++++++--------------- qapi/qmp-output-visitor.c | 2 +- qom/object.c | 5 ++--- scripts/qapi-event.py | 3 ++- scripts/qapi-visit.py | 9 ++++----- tests/test-qmp-input-visitor.c | 3 ++- vl.c | 11 +++++------ 15 files changed, 85 insertions(+), 51 deletions(-)