On Tue, 19 Jul 2022 13:52:46 -0700 ira.weiny@xxxxxxxxx wrote: > From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > Introduced in a PCIe r6.0, sec 6.30, DOE provides a config space based > mailbox with standard protocol discovery. Each mailbox is accessed > through a DOE Extended Capability. > > Each DOE mailbox must support the DOE discovery protocol in addition to > any number of additional protocols. > > Define core PCIe functionality to manage a single PCIe DOE mailbox at a > defined config space offset. Functionality includes iterating, > creating, query of supported protocol, and task submission. Destruction > of the mailboxes is device managed. > > Cc: "Li, Ming" <ming4.li@xxxxxxxxx> > Cc: Bjorn Helgaas <helgaas@xxxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> > Acked-by: Bjorn Helgaas <helgaas@xxxxxxxxxx> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > Co-developed-by: Ira Weiny <ira.weiny@xxxxxxxxx> > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> FYI. Gregory Price reported an an issue that I think is related to calling INIT_WORK() rather than INIT_WORK_ONSTACK() and associated debug options in his build. https://lore.kernel.org/linux-cxl/20221014151045.24781-1-Jonathan.Cameron@xxxxxxxxxx/T/#m88a7f50dcce52f30c8bf5c3dcc06fa9843b54a2d I've highlighted one path to this below. > diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c > new file mode 100644 > index 000000000000..e402f05068a5 > --- /dev/null > +++ b/drivers/pci/doe.c > @@ -0,0 +1,536 @@ > +static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid, > + u8 *protocol) > +{ > + u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX, > + *index); > + u32 response_pl; > + DECLARE_COMPLETION_ONSTACK(c); > + struct pci_doe_task task = { > + .prot.vid = PCI_VENDOR_ID_PCI_SIG, > + .prot.type = PCI_DOE_PROTOCOL_DISCOVERY, > + .request_pl = &request_pl, > + .request_pl_sz = sizeof(request_pl), > + .response_pl = &response_pl, > + .response_pl_sz = sizeof(response_pl), > + .complete = pci_doe_task_complete, > + .private = &c, > + }; This structure contains a work_struct and is on the stack. However... > + int rc; > + > + rc = pci_doe_submit_task(doe_mb, &task); > + if (rc < 0) > + return rc; > + > + wait_for_completion(&c); > + > + if (task.rv != sizeof(response_pl)) > + return -EIO; > + > + *vid = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID, response_pl); > + *protocol = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL, > + response_pl); > + *index = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX, > + response_pl); > + > + return 0; > +} ... > +int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task) > +{ > + if (!pci_doe_supports_prot(doe_mb, task->prot.vid, task->prot.type)) > + return -EINVAL; > + > + /* > + * DOE requests must be a whole number of DW and the response needs to > + * be big enough for at least 1 DW > + */ > + if (task->request_pl_sz % sizeof(u32) || > + task->response_pl_sz < sizeof(u32)) > + return -EINVAL; > + > + if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags)) > + return -EIO; > + > + task->doe_mb = doe_mb; > + INIT_WORK(&task->work, doe_statemachine_work); Here we don't call the INIT_WORK_ONSTACK() Variant. > + queue_work(doe_mb->work_queue, &task->work); > + return 0; > +} > +EXPORT_SYMBOL_GPL(pci_doe_submit_task);
