PCI: endpoint: Finish virtual EP removal in pci_epf_remove_vepf()

When removing a virtual Endpoint, pci_epf_remove_vepf() failed to clear
epf_vf->epf_pf, which caused a subsequent pci_epf_add_vepf() to incorrectly
return -EBUSY:

  pci_epf_add_vepf(epf_pf, epf_vf)      // add
  pci_epf_remove_vepf(epf_pf, epf_vf)   // remove
  pci_epf_add_vepf(epf_pf, epf_vf)      // add again, -EBUSY error

Fix by clearing epf_vf->epf_pf in pci_epf_remove_vepf().

Link: https://lore.kernel.org/r/20241210-pci-epc-core_fix-v3-3-4d86dd573e4b@quicinc.com
Fixes: 1cf362e907f3 ("PCI: endpoint: Add support to add virtual function in endpoint core")
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index 8fa2797d4169a9f21136bbf73daa818da6c4ac49..50bc2892a36c54aa82c819ac5a9c99e9155d92c1 100644 (file)
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -202,6 +202,7 @@ void pci_epf_remove_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf)
 
        mutex_lock(&epf_pf->lock);
        clear_bit(epf_vf->vfunc_no, &epf_pf->vfunction_num_map);
+       epf_vf->epf_pf = NULL;
        list_del(&epf_vf->list);
        mutex_unlock(&epf_pf->lock);
 }