On Tue, 24 Aug 2021 09:07:13 -0700 Dan Williams <[email protected]> wrote:
> The CXL_PMEM driver expects exclusive control of the label storage area > space. Similar to the LIBNVDIMM expectation that the label storage area > is only writable from userspace when the corresponding memory device is > not active in any region, the expectation is the native CXL_PCI UAPI > path is disabled while the cxl_nvdimm for a given cxl_memdev device is > active in LIBNVDIMM. > > Add the ability to toggle the availability of a given command for the > UAPI path. Use that new capability to shutdown changes to partitions and > the label storage area while the cxl_nvdimm device is actively proxying > commands for LIBNVDIMM. > > Acked-by: Ben Widawsky <[email protected]> > Signed-off-by: Dan Williams <[email protected]> > --- > drivers/cxl/core/mbox.c | 5 +++++ > drivers/cxl/core/memdev.c | 31 +++++++++++++++++++++++++++++++ > drivers/cxl/cxlmem.h | 4 ++++ > drivers/cxl/pmem.c | 35 ++++++++++++++++++++++++++++------- > 4 files changed, 68 insertions(+), 7 deletions(-) > > diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c > index 73107b302224..6a5c4f3679ba 100644 > --- a/drivers/cxl/core/mbox.c > +++ b/drivers/cxl/core/mbox.c > @@ -230,6 +230,7 @@ static bool cxl_mem_raw_command_allowed(u16 opcode) > * * %-EINVAL - Reserved fields or invalid values were used. > * * %-ENOMEM - Input or output buffer wasn't sized properly. > * * %-EPERM - Attempted to use a protected command. > + * * %-EBUSY - Kernel has claimed exclusive access to this opcode > * > * The result of this command is a fully validated command in @out_cmd that > is > * safe to send to the hardware. > @@ -305,6 +306,10 @@ static int cxl_validate_cmd_from_user(struct cxl_mem > *cxlm, > if (!test_bit(info->id, cxlm->enabled_cmds)) > return -ENOTTY; > > + /* Check that the command is not claimed for exclusive kernel use */ > + if (test_bit(info->id, cxlm->exclusive_cmds)) > + return -EBUSY; > + > /* Check the input buffer is the expected size */ > if (info->size_in >= 0 && info->size_in != send_cmd->in.size) > return -ENOMEM; > #endif /* __CXL_MEM_H__ */ > diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c > index 9652c3ee41e7..469b984176a2 100644 > --- a/drivers/cxl/pmem.c > +++ b/drivers/cxl/pmem.c > @@ -16,9 +16,21 @@ > */ > static struct workqueue_struct *cxl_pmem_wq; > > -static void unregister_nvdimm(void *nvdimm) > +static __read_mostly DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX); > + > +static void unregister_nvdimm(void *_cxl_nvd) > { > - nvdimm_delete(nvdimm); > + struct cxl_nvdimm *cxl_nvd = _cxl_nvd; > + struct cxl_memdev *cxlmd = cxl_nvd->cxlmd; > + struct cxl_mem *cxlm = cxlmd->cxlm; > + struct device *dev = &cxl_nvd->dev; > + struct nvdimm *nvdimm; > + > + nvdimm = dev_get_drvdata(dev); > + if (nvdimm) > + nvdimm_delete(nvdimm); > + > + clear_exclusive_cxl_commands(cxlm, exclusive_cmds); > } > > static int match_nvdimm_bridge(struct device *dev, const void *data) > @@ -39,9 +51,11 @@ static struct cxl_nvdimm_bridge > *cxl_find_nvdimm_bridge(void) > static int cxl_nvdimm_probe(struct device *dev) > { > struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev); > + struct cxl_memdev *cxlmd = cxl_nvd->cxlmd; > + struct cxl_mem *cxlm = cxlmd->cxlm; > struct cxl_nvdimm_bridge *cxl_nvb; > + struct nvdimm *nvdimm = NULL; > unsigned long flags = 0; > - struct nvdimm *nvdimm; > int rc = -ENXIO; > > cxl_nvb = cxl_find_nvdimm_bridge(); > @@ -52,17 +66,20 @@ static int cxl_nvdimm_probe(struct device *dev) > if (!cxl_nvb->nvdimm_bus) > goto out; > > + set_exclusive_cxl_commands(cxlm, exclusive_cmds); > + > set_bit(NDD_LABELING, &flags); > nvdimm = nvdimm_create(cxl_nvb->nvdimm_bus, cxl_nvd, NULL, flags, 0, 0, > NULL); > - if (!nvdimm) > - goto out; > - > - rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm); > + dev_set_drvdata(dev, nvdimm); > + rc = devm_add_action_or_reset(dev, unregister_nvdimm, cxl_nvd); I think this ends up less readable than explicit devm handling of each part rather than combining them. set_exclusive...() rc = devm_add_action_or_rset(dev, unset_exclusive, cxlm); if (rc) goto out; nvidimm = nvdim_create() if (!nvdimm) //return value looks dubious in old code but I've not checked it properly. goto out; rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm); if (rc) goto out; dev_set_drvdata(dev, nvdimm); and two simpler unwinding functions doing just one thing each. > out: > device_unlock(&cxl_nvb->dev); > put_device(&cxl_nvb->dev); > > + if (!nvdimm && rc == 0) > + rc = -ENOMEM; > + > return rc; > } > > @@ -194,6 +211,10 @@ static __init int cxl_pmem_init(void) > { > int rc; > > + set_bit(CXL_MEM_COMMAND_ID_SET_PARTITION_INFO, exclusive_cmds); > + set_bit(CXL_MEM_COMMAND_ID_SET_SHUTDOWN_STATE, exclusive_cmds); > + set_bit(CXL_MEM_COMMAND_ID_SET_LSA, exclusive_cmds); > + > cxl_pmem_wq = alloc_ordered_workqueue("cxl_pmem", 0); > if (!cxl_pmem_wq) > return -ENXIO; >
