qemu/hw/s390x/virtio-ccw-rng.c
Markus Armbruster 668f62ec62 error: Eliminate error_propagate() with Coccinelle, part 1
When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away.  Convert

    if (!foo(..., &err)) {
        ...
        error_propagate(errp, err);
        ...
        return ...
    }

to

    if (!foo(..., errp)) {
        ...
        ...
        return ...
    }

where nothing else needs @err.  Coccinelle script:

    @rule1 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
         if (
    (
    -        fun(args, &err, args2)
    +        fun(args, errp, args2)
    |
    -        !fun(args, &err, args2)
    +        !fun(args, errp, args2)
    |
    -        fun(args, &err, args2) op c1
    +        fun(args, errp, args2) op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    )
         }

    @rule2 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    expression var;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
    -    var = fun(args, &err, args2);
    +    var = fun(args, errp, args2);
         ... when != err
         if (
    (
             var
    |
             !var
    |
             var op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    |
             return var;
    )
         }

    @depends on rule1 || rule2@
    identifier err;
    @@
    -    Error *err = NULL;
         ... when != err

Not exactly elegant, I'm afraid.

The "when != lbl:" is necessary to avoid transforming

         if (fun(args, &err)) {
             goto out
         }
         ...
     out:
         error_propagate(errp, err);

even though other paths to label out still need the error_propagate().
For an actual example, see sclp_realize().

Without the "when strict", Coccinelle transforms vfio_msix_setup(),
incorrectly.  I don't know what exactly "when strict" does, only that
it helps here.

The match of return is narrower than what I want, but I can't figure
out how to express "return where the operand doesn't use @err".  For
an example where it's too narrow, see vfio_intx_enable().

Silently fails to convert hw/arm/armsse.c, because Coccinelle gets
confused by ARMSSE being used both as typedef and function-like macro
there.  Converted manually.

Line breaks tidied up manually.  One nested declaration of @local_err
deleted manually.  Preexisting unwanted blank line dropped in
hw/riscv/sifive_e.c.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-35-armbru@redhat.com>
2020-07-10 15:18:08 +02:00

72 lines
2.1 KiB
C

/*
* virtio ccw random number generator implementation
*
* Copyright 2012, 2015 IBM Corp.
* Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#include "qemu/osdep.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/virtio.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "virtio-ccw.h"
static void virtio_ccw_rng_realize(VirtioCcwDevice *ccw_dev, Error **errp)
{
VirtIORNGCcw *dev = VIRTIO_RNG_CCW(ccw_dev);
DeviceState *vdev = DEVICE(&dev->vdev);
if (!qdev_realize(vdev, BUS(&ccw_dev->bus), errp)) {
return;
}
object_property_set_link(OBJECT(dev), "rng", OBJECT(dev->vdev.conf.rng),
NULL);
}
static void virtio_ccw_rng_instance_init(Object *obj)
{
VirtIORNGCcw *dev = VIRTIO_RNG_CCW(obj);
virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
TYPE_VIRTIO_RNG);
}
static Property virtio_ccw_rng_properties[] = {
DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
VIRTIO_CCW_MAX_REV),
DEFINE_PROP_END_OF_LIST(),
};
static void virtio_ccw_rng_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtIOCCWDeviceClass *k = VIRTIO_CCW_DEVICE_CLASS(klass);
k->realize = virtio_ccw_rng_realize;
device_class_set_props(dc, virtio_ccw_rng_properties);
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
}
static const TypeInfo virtio_ccw_rng = {
.name = TYPE_VIRTIO_RNG_CCW,
.parent = TYPE_VIRTIO_CCW_DEVICE,
.instance_size = sizeof(VirtIORNGCcw),
.instance_init = virtio_ccw_rng_instance_init,
.class_init = virtio_ccw_rng_class_init,
};
static void virtio_ccw_rng_register(void)
{
type_register_static(&virtio_ccw_rng);
}
type_init(virtio_ccw_rng_register)