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Re: [PATCH v3 1/2] hw/nvme: fix incorrect use of errp/local_err
From: |
Markus Armbruster |
Subject: |
Re: [PATCH v3 1/2] hw/nvme: fix incorrect use of errp/local_err |
Date: |
Fri, 11 Nov 2022 12:17:42 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) |
Klaus Jensen <its@irrelevant.dk> writes:
> 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 ;)
Reviewed-by: Markus Armbruster <armbru@redhat.com>