[libvirt] [PATCH 12/15] util: pci: Introduce virPCIGetMdevTypes helper

[Erik Skultety]

On Mon, Jan 29, 2018 at 02:02:19PM +0100, Michal Privoznik wrote
> On 01/29/2018 01:24 PM, Erik Skultety wrote:
> > On Fri, Jan 26, 2018 at 12:39:00PM +0100, Michal Privoznik wrote:
> >> On 01/25/2018 10:23 AM, Erik Skultety wrote:
> >>> This is a replacement for the existing udevPCIGetMdevTypesCap which is
> >>> static to the udev backend. This simple helper constructs the sysfs path
> >>> from the device's base path for each mdev type and queries the
> >>> corresponding attributes of that type.
> >>>
> >>> Signed-off-by: Erik Skultety <eskultet at redhat.com>
> >>> ---
> >>>  src/libvirt_private.syms |  1 +
> >>>  src/util/virpci.c        | 58 ++++++++++++++++++++++++++++++++++++++++++++++++
> >>>  src/util/virpci.h        |  4 ++++
> >>>  3 files changed, 63 insertions(+)
> >>>
> >>> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> >>> index 75eaf1d4c..8d4c8dd3f 100644
> >>> --- a/src/libvirt_private.syms
> >>> +++ b/src/libvirt_private.syms
> >>> @@ -2456,6 +2456,7 @@ virPCIDeviceWaitForCleanup;
> >>>  virPCIEDeviceInfoFree;
> >>>  virPCIGetDeviceAddressFromSysfsLink;
> >>>  virPCIGetHeaderType;
> >>> +virPCIGetMdevTypes;
> >>>  virPCIGetNetName;
> >>>  virPCIGetPhysicalFunction;
> >>>  virPCIGetVirtualFunctionIndex;
> >>> diff --git a/src/util/virpci.c b/src/util/virpci.c
> >>> index fe57bef32..12d7ef0e4 100644
> >>> --- a/src/util/virpci.c
> >>> +++ b/src/util/virpci.c
> >>> @@ -3027,6 +3027,64 @@ virPCIGetVirtualFunctionInfo(const char *vf_sysfs_device_path,
> >>>      return ret;
> >>>  }
> >>>
> >>> +
> >>> +int
> >>> +virPCIGetMdevTypes(const char *sysfspath,
> >>> +                   virMediatedDeviceTypePtr **types)
> >>
> >> Since this function returns size_t on success, I guess the retval should
> >> be type of ssize_t at least. We are not guaranteed that size_t will fit
> >
> > ssize_t wouldn't really help, since assigning size_t might overflow, so the
> > only safe bet is long long, but I mean, do you really expect there to be more
> > than INT_MAX mdev types for a device? That would be a lot of types to support.
>
> In kernel, they do a lot of size_t -> ssize_t conversion in cases
> where's it's next to impossible to overflow. And I believe this is one
> of them.

Fair enough, consider it changed.

Erik