[RFC v5 052/126] vhost: 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 == &fatal_err
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

If we want to check error after errp-function call, we need to
introduce local_err and than propagate it to errp. Instead, use
ERRP_AUTO_PROPAGATE macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
   &error_fatel, this means that we don't break error_abort
   (we'll abort on error_set, not on error_propagate)

This commit (together with its neighbors) was generated by

for f in $(git grep -l errp \*.[ch]); do \
    spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
    --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
done;

then fix a bit of compilation problems: coccinelle for some reason
leaves several
f() {
    ...
    goto out;
    ...
    out:
}
patterns, with "out:" at function end.

then
./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"

(auto-msg was a file with this commit message)

Still, for backporting it may be more comfortable to use only the first
command and then do one huge commit.

Reported-by: Kevin Wolf <address@hidden>
Reported-by: Greg Kurz <address@hidden>
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
 hw/block/vhost-user-blk.c |  6 +++---
 hw/scsi/vhost-scsi.c      | 12 +++++-------
 hw/scsi/vhost-user-scsi.c |  7 +++----
 hw/virtio/vhost-vsock.c   |  1 +
 4 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index 63da9bb619..9dfe173c19 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -388,9 +388,9 @@ static void vhost_user_blk_event(void *opaque, int event)
 
 static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
-    Error *err = NULL;
     int i, ret;
 
     if (!s->chardev.chr) {
@@ -429,8 +429,8 @@ static void vhost_user_blk_device_realize(DeviceState *dev, 
Error **errp)
                              NULL, (void *)dev, NULL, true);
 
 reconnect:
-    if (qemu_chr_fe_wait_connected(&s->chardev, &err) < 0) {
-        error_report_err(err);
+    if (qemu_chr_fe_wait_connected(&s->chardev, errp) < 0) {
+        error_report_errp(errp);
         goto virtio_err;
     }
 
diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index c693fc748a..2dca1f7fe2 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -165,9 +165,9 @@ static const VMStateDescription vmstate_virtio_vhost_scsi = 
{
 
 static void vhost_scsi_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
     VHostSCSICommon *vsc = VHOST_SCSI_COMMON(dev);
-    Error *err = NULL;
     int vhostfd = -1;
     int ret;
 
@@ -195,9 +195,8 @@ static void vhost_scsi_realize(DeviceState *dev, Error 
**errp)
                                vhost_dummy_handle_output,
                                vhost_dummy_handle_output,
                                vhost_dummy_handle_output,
-                               &err);
-    if (err != NULL) {
-        error_propagate(errp, err);
+                               errp);
+    if (*errp) {
         goto close_fd;
     }
 
@@ -207,9 +206,8 @@ static void vhost_scsi_realize(DeviceState *dev, Error 
**errp)
                 "When external environment supports it (Orchestrator migrates "
                 "target SCSI device state or use shared storage over network), 
"
                 "set 'migratable' property to true to enable migration.");
-        migrate_add_blocker(vsc->migration_blocker, &err);
-        if (err) {
-            error_propagate(errp, err);
+        migrate_add_blocker(vsc->migration_blocker, errp);
+        if (*errp) {
             error_free(vsc->migration_blocker);
             goto free_virtio;
         }
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index 6a6c15dd32..ef4b25104f 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -68,11 +68,11 @@ static void vhost_dummy_handle_output(VirtIODevice *vdev, 
VirtQueue *vq)
 
 static void vhost_user_scsi_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
     VHostUserSCSI *s = VHOST_USER_SCSI(dev);
     VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
     struct vhost_virtqueue *vqs = NULL;
-    Error *err = NULL;
     int ret;
 
     if (!vs->conf.chardev.chr) {
@@ -82,9 +82,8 @@ static void vhost_user_scsi_realize(DeviceState *dev, Error 
**errp)
 
     virtio_scsi_common_realize(dev, vhost_dummy_handle_output,
                                vhost_dummy_handle_output,
-                               vhost_dummy_handle_output, &err);
-    if (err != NULL) {
-        error_propagate(errp, err);
+                               vhost_dummy_handle_output, errp);
+    if (*errp) {
         return;
     }
 
diff --git a/hw/virtio/vhost-vsock.c b/hw/virtio/vhost-vsock.c
index f5744363a8..61ade0fa65 100644
--- a/hw/virtio/vhost-vsock.c
+++ b/hw/virtio/vhost-vsock.c
@@ -300,6 +300,7 @@ static const VMStateDescription vmstate_virtio_vhost_vsock 
= {
 
 static void vhost_vsock_device_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostVSock *vsock = VHOST_VSOCK(dev);
     int vhostfd;
-- 
2.21.0