Re: [PATCH v2 4/4] vfio/ccw: Make vfio_ccw_register_irq_notifier() return a bool

[Cédric Le Goater]

On 4/25/24 14:55, Eric Farman wrote:

On Thu, 2024-04-25 at 12:56 +0200, Markus Armbruster wrote:

Cédric Le Goater <c...@redhat.com> writes:

Since vfio_ccw_register_irq_notifier() takes an 'Error **'
argument,
best practices suggest to return a bool. See the qapi/error.h Rules
section.

Signed-off-by: Cédric Le Goater <c...@redhat.com>
---
  hw/vfio/ccw.c | 22 +++++++++++-----------
  1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
index
6764388bc47a970329fce2233626ccb8178e0165..1c630f6e9abe93ae0c2b5615d
4409669f096c8c9 100644
--- a/hw/vfio/ccw.c
+++ b/hw/vfio/ccw.c
@@ -379,7 +379,7 @@ read_err:
      css_inject_io_interrupt(sch);
  }

-static void vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,

+static bool vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
                                             unsigned int irq,
                                             Error **errp)
  {
@@ -405,13 +405,13 @@ static void
vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
          break;
      default:
          error_setg(errp, "vfio: Unsupported device irq(%d)", irq);
-        return;
+        return false;
      }

     if (vdev->num_irqs < irq + 1) {

          error_setg(errp, "vfio: IRQ %u not available (number of
irqs %u)",
                     irq, vdev->num_irqs);
-        return;
+        return false;
      }

     argsz = sizeof(*irq_info);

@@ -421,14 +421,14 @@ static void
vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
      if (ioctl(vdev->fd, VFIO_DEVICE_GET_IRQ_INFO,
                irq_info) < 0 || irq_info->count < 1) {
          error_setg_errno(errp, errno, "vfio: Error getting irq
info");
-        return;
+        return false;
      }

     if (event_notifier_init(notifier, 0)) {

          error_setg_errno(errp, errno,
                           "vfio: Unable to init event notifier for
irq (%d)",
                           irq);
-        return;
+        return false;
      }

     fd = event_notifier_get_fd(notifier);

@@ -439,6 +439,8 @@ static void
vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
          qemu_set_fd_handler(fd, NULL, NULL, vcdev);
          event_notifier_cleanup(notifier);
      }
+
+    return true;
  }

 static void vfio_ccw_unregister_irq_notifier(VFIOCCWDevice *vcdev,

@@ -602,20 +604,18 @@ static void vfio_ccw_realize(DeviceState
*dev, Error **errp)
          goto out_region_err;
      }

-    vfio_ccw_register_irq_notifier(vcdev, VFIO_CCW_IO_IRQ_INDEX,

&err);
-    if (err) {
+    if (!vfio_ccw_register_irq_notifier(vcdev,
VFIO_CCW_IO_IRQ_INDEX, &err)) {

Please pass errp instead of &err.

          goto out_io_notifier_err;
      }

     if (vcdev->crw_region) {

-        vfio_ccw_register_irq_notifier(vcdev,
VFIO_CCW_CRW_IRQ_INDEX, &err);
-        if (err) {
+        if (!vfio_ccw_register_irq_notifier(vcdev,
VFIO_CCW_CRW_IRQ_INDEX,
+                                            &err)) {

Likewise.

              goto out_irq_notifier_err;
          }
      }

-    vfio_ccw_register_irq_notifier(vcdev, VFIO_CCW_REQ_IRQ_INDEX,

&err);
-    if (err) {
+    if (!vfio_ccw_register_irq_notifier(vcdev,
VFIO_CCW_REQ_IRQ_INDEX, &err)) {
          /*
           * Report this error, but do not make it a failing
condition.
           * Lack of this IRQ in the host does not prevent normal
operation.

             */
            error_report_err(err);

Not this patch's problem, but here goes anyway: since this isn't an
error, we shouldn't use error_report_err().  Would warn_report_err()
be
appropriate?  info_report_err() doesn't exist, but it could.

Preferably with errp instead of &err (two times):
Reviewed-by: Markus Armbruster <arm...@redhat.com>

Don't recall why I used error_report_err() instead of something else
(or creating info_), but probably just familiarity. There's no need for
it (or the equivalent code in -ap) to be error, and could be another
cleanup.

yes. I will send an extra cleanup to replace error_... with warn_...
and another one to use errp.

Thanks,

C.

Reviewed-by: Eric Farman <far...@linux.ibm.com>