Re: [PATCH v3 1/2] hw/nvme: fix incorrect use of errp/local_err

[Klaus Jensen]

On Nov 11 07:55, Markus Armbruster wrote:
> Klaus Jensen <its@irrelevant.dk> writes:
> 
> > On Nov 11 07:36, Markus Armbruster wrote:
> >> Klaus Jensen <its@irrelevant.dk> writes:
> >> 
> >> > From: Klaus Jensen <k.jensen@samsung.com>
> >> >
> >> > Remove an unnecessary local Error value in nvme_realize(). In the
> >> > process, change nvme_check_constraints() into returning a bool.
> >> >
> >> > Finally, removing the local Error value also fixes a bug where an error
> >> > returned from nvme_init_subsys() would be lost.
> >> 
> >> Would it be lost?  It's the hunk below:
> >> 
> >> > Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> >> > Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> >> > ---
> >> >  hw/nvme/ctrl.c | 48 +++++++++++++++++++++++-------------------------
> >> >  1 file changed, 23 insertions(+), 25 deletions(-)
> >> >
> >> > diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
> >> > index ac3885ce5079..a5c0a5fa6ce2 100644
> >> > --- a/hw/nvme/ctrl.c
> >> > +++ b/hw/nvme/ctrl.c
> >> 
> >> [...]
> >> 
> >> > @@ -7586,7 +7585,6 @@ static void nvme_realize(PCIDevice *pci_dev, Error 
> >> > **errp)
> >>    static void nvme_realize(PCIDevice *pci_dev, Error **errp)
> >>    {
> >>        NvmeCtrl *n = NVME(pci_dev);
> >>        NvmeNamespace *ns;
> >>        Error *local_err = NULL;
> >> 
> >> @local_err is null.
> >> 
> >>        NvmeCtrl *pn = NVME(pcie_sriov_get_pf(pci_dev));
> >> 
> >>        if (pci_is_vf(pci_dev)) {
> >>            /*
> >>             * VFs derive settings from the parent. PF's lifespan exceeds
> >>             * that of VF's, so it's safe to share params.serial.
> >>             */
> >>            memcpy(&n->params, &pn->params, sizeof(NvmeParams));
> >>            n->subsys = pn->subsys;
> >>        }
> >> 
> >>        nvme_check_constraints(n, &local_err);
> >>        if (local_err) {
> >>            error_propagate(errp, local_err);
> >>            return;
> >>        }
> >> 
> >> @local_err still is null.
> >> 
> >>        qbus_init(&n->bus, sizeof(NvmeBus), TYPE_NVME_BUS,
> >> >                &pci_dev->qdev, n->parent_obj.qdev.id);
> >> >  
> >> >      if (nvme_init_subsys(n, errp)) {
> >> > -        error_propagate(errp, local_err);
> >> 
> >> Since @local_err is null, this error_propagate() does nothing.  The
> >> error from nvme_init_subsys() remains in @errp.
> >> 
> >
> > Oh, right. Thanks.
> >
> > I misread the function documentation, getting the impression that it
> > would overwrite dst_errp regardless of the value of local_err.
> 
> Happens :)
> 
> If you have suggestions on improving the doc, shoot.
> 
> This commit's message could perhaps be adjusted like
> 
>     hw/nvme: Clean up confused use of errp/local_err
> 
>     Remove an unnecessary local Error value in nvme_realize(). In the
>     process, change nvme_check_constraints() to return a bool.
> 
> What do you think?
> 

Sounds good ;)

signature.asc
Description: PGP signature