[libvirt] [PATCH 03/15] conf: nodedev: Convert virNodeDevObjHasCapStr to a simple wrapper

[Erik Skultety]

On Fri, Jan 26, 2018 at 12:40:34PM +0100, Michal Privoznik wrote:
> On 01/25/2018 10:23 AM, Erik Skultety wrote:
> > This patch drops the capability matching redundancy by simply converting
> > the string input to our internal types which are then in turn used for
> > the actual capability matching.
> >
> > Signed-off-by: Erik Skultety <eskultet at redhat.com>
> > ---
> >  src/conf/virnodedeviceobj.c | 50 +--------------------------------------------
> >  1 file changed, 1 insertion(+), 49 deletions(-)
> >
> > diff --git a/src/conf/virnodedeviceobj.c b/src/conf/virnodedeviceobj.c
> > index ccad59a4b..5360df805 100644
> > --- a/src/conf/virnodedeviceobj.c
> > +++ b/src/conf/virnodedeviceobj.c
> > @@ -128,55 +128,7 @@ static bool
> >  virNodeDeviceObjHasCapStr(const virNodeDeviceObj *obj,
> >                            const char *cap)
> >  {
> > -    virNodeDevCapsDefPtr caps = obj->def->caps;
> > -    const char *fc_host_cap =
> > -        virNodeDevCapTypeToString(VIR_NODE_DEV_CAP_FC_HOST);
> > -    const char *vports_cap =
> > -        virNodeDevCapTypeToString(VIR_NODE_DEV_CAP_VPORTS);
> > -    const char *mdev_types =
> > -        virNodeDevCapTypeToString(VIR_NODE_DEV_CAP_MDEV_TYPES);
> > -
> > -    while (caps) {
> > -        if (STREQ(cap, virNodeDevCapTypeToString(caps->data.type))) {
> > -            return true;
> > -        } else {
> > -            switch (caps->data.type) {
> > -            case VIR_NODE_DEV_CAP_PCI_DEV:
> > -                if ((STREQ(cap, mdev_types)) &&
> > -                    (caps->data.pci_dev.flags & VIR_NODE_DEV_CAP_FLAG_PCI_MDEV))
> > -                    return true;
> > -                break;
> > -
> > -            case VIR_NODE_DEV_CAP_SCSI_HOST:
> > -                if ((STREQ(cap, fc_host_cap) &&
> > -                    (caps->data.scsi_host.flags & VIR_NODE_DEV_CAP_FLAG_HBA_FC_HOST)) ||
> > -                    (STREQ(cap, vports_cap) &&
> > -                    (caps->data.scsi_host.flags & VIR_NODE_DEV_CAP_FLAG_HBA_VPORT_OPS)))
> > -                    return true;
> > -                break;
> > -
> > -            case VIR_NODE_DEV_CAP_SYSTEM:
> > -            case VIR_NODE_DEV_CAP_USB_DEV:
> > -            case VIR_NODE_DEV_CAP_USB_INTERFACE:
> > -            case VIR_NODE_DEV_CAP_NET:
> > -            case VIR_NODE_DEV_CAP_SCSI_TARGET:
> > -            case VIR_NODE_DEV_CAP_SCSI:
> > -            case VIR_NODE_DEV_CAP_STORAGE:
> > -            case VIR_NODE_DEV_CAP_FC_HOST:
> > -            case VIR_NODE_DEV_CAP_VPORTS:
> > -            case VIR_NODE_DEV_CAP_SCSI_GENERIC:
> > -            case VIR_NODE_DEV_CAP_DRM:
> > -            case VIR_NODE_DEV_CAP_MDEV_TYPES:
> > -            case VIR_NODE_DEV_CAP_MDEV:
> > -            case VIR_NODE_DEV_CAP_CCW_DEV:
> > -            case VIR_NODE_DEV_CAP_LAST:
> > -                break;
> > -            }
> > -        }
> > -
> > -        caps = caps->next;
> > -    }
> > -    return false;
> > +    return virNodeDeviceObjHasCap(obj, virNodeDevCapTypeFromString(cap));
>
> I wonder if we should check for the TypeFromString() conversion rather
> than pass it to the other function directly.

Well, since the conversion function returns -1 on unknown types and none of our
device cap enum types can ever be equal to -1, since that would make it
non-deterministic, but I agree that by adding a check explicitly we can save a
few cycles, may I assume this to be an ACK with the following squashed in?

diff --git a/src/conf/virnodedeviceobj.c b/src/conf/virnodedeviceobj.c
index 2f37c4a05..ccea10793 100644
--- a/src/conf/virnodedeviceobj.c
+++ b/src/conf/virnodedeviceobj.c
@@ -124,7 +124,12 @@ static bool
 virNodeDeviceObjHasCapStr(const virNodeDeviceObj *obj,
                           const char *cap)
 {
-    return virNodeDeviceObjHasCap(obj, virNodeDevCapTypeFromString(cap));
+    int type;
+
+    if ((type = virNodeDevCapTypeFromString(cap)) < 0)
+        return false;
+
+    return virNodeDeviceObjHasCap(obj, type);
 }


Erik