xen: Use ERRP_GUARD()

If we want to check error after errp-function call, we need to
introduce local_err and then propagate it to errp. Instead, use
the ERRP_GUARD() macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_GUARD() 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)

If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_GUARD() 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).  No such cases are being fixed here.

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/errp-guard.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>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200707165037.1026246-9-armbru@redhat.com>
[ERRP_AUTO_PROPAGATE() renamed to ERRP_GUARD(), and
auto-propagated-errp.cocci to errp-guard.cocci.  Commit message
tweaked again.]

5 files changed, 75 insertions, 93 deletions

diff --git a/hw/xen/xen-backend.c b/hw/xen/xen-backend.c
index da065f81b7..10199fb58d 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_GUARD();
     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 c4e2162ae9..9ce1c9540b 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_GUARD();
     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_GUARD();
     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_GUARD();
     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);
     }
 }
 
@@ -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_GUARD();
     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_GUARD();
     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: ");
     }
 }
 
@@ -1247,11 +1237,11 @@ static void xen_device_exit(Notifier *n, void *data)
 
 static void xen_device_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_GUARD();
     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;
@@ -1267,10 +1257,9 @@ 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;
     }
 
@@ -1293,22 +1282,19 @@ 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..8c6e9a1716 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_GUARD();
     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 ab84443d5e..6d359ee486 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -777,12 +777,12 @@ static void xen_pt_destroy(PCIDevice *d) {
 
 static void xen_pt_realize(PCIDevice *d, Error **errp)
 {
+    ERRP_GUARD();
     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"
@@ -793,10 +793,9 @@ 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;
     }
 
@@ -823,11 +822,10 @@ 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;
         }
@@ -840,10 +838,9 @@ 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 d0d7c720a6..c8724cc7c8 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_GUARD();
     int i, rc;
-    Error *err = NULL;
 
     QLIST_INIT(&s->reg_grps);
 
@@ -2067,13 +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;
                     }