[PATCH v6 17/18] nvmet: New NVMe PCI endpoint function target driver

[Manivannan Sadhasivam]

On Fri, Dec 20, 2024 at 01:42:29PM +0530, Manivannan Sadhasivam wrote:

[...]

Sorry, forgot to trim my reply.

> > +static void nvmet_pci_epf_clear_bar(struct nvmet_pci_epf *nvme_epf)
> > +{
> > +	struct pci_epf *epf = nvme_epf->epf;
> > +
> > +	pci_epc_clear_bar(epf->epc, epf->func_no, epf->vfunc_no,
> > +			  &epf->bar[BAR_0]);
> > +	pci_epf_free_space(epf, nvme_epf->reg_bar, BAR_0, PRIMARY_INTERFACE);
> > +	nvme_epf->reg_bar = NULL;
> 
> Memory for BAR 0 is allocated in nvmet_pci_epf_bind(), but it is freed in both
> nvmet_pci_epf_epc_deinit() and nvmet_pci_epf_bind(). This will cause NULL ptr
> dereference if epc_deinit() gets called after nvmet_pci_epf_bind() and then
> epc_init() is called (we call epc_deinit() once PERST# is deasserted to cleanup
> the EPF for platforms requiring refclk from host).
> 
> So please move pci_epf_free_space() and 'nvme_epf->reg_bar = NULL' to a
> separate helper nvmet_pci_epf_free_bar() and call that only from
> nvmet_pci_epf_unbind() (outside of 'epc->init_complete' check).
> 
> With the above change, I'm able to get this EPF driver working on my Qcom RC/EP
> setup.
> 
> - Mani

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