| Message ID | 164610295187.2682974.18123746840987009597.stgit@dwillia2-desk3.amr.corp.intel.com |
|---|---|
| State | New, archived |
| Headers | show |
| Series | device-core: Generic device-lock lockdep validation | expand |
On Mon, 28 Feb 2022 18:49:11 -0800 Dan Williams <dan.j.williams@intel.com> wrote: > MAX_LOCKDEP_SUBCLASSES limits the depth of the CXL topology that can be > validated by lockdep. Given that the cxl_test topology is already at > this limit collapse some of the levels and clamp the max depth. > > Cc: Alison Schofield <alison.schofield@intel.com> > Cc: Vishal Verma <vishal.l.verma@intel.com> > Cc: Ira Weiny <ira.weiny@intel.com> > Cc: Ben Widawsky <ben.widawsky@intel.com> > Signed-off-by: Dan Williams <dan.j.williams@intel.com> > --- > drivers/cxl/cxl.h | 21 +++++++++++++++++---- > 1 file changed, 17 insertions(+), 4 deletions(-) > > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > index 97e6ca7e4940..1357a245037d 100644 > --- a/drivers/cxl/cxl.h > +++ b/drivers/cxl/cxl.h > @@ -501,20 +501,33 @@ enum cxl_lock_class { > CXL_ANON_LOCK, > CXL_NVDIMM_LOCK, > CXL_NVDIMM_BRIDGE_LOCK, I'd be tempted to give explicit value to the one above as well so it's immediate clear there is deliberate duplication here. > - CXL_PORT_LOCK, > + CXL_PORT_LOCK = 2, > /* > * Be careful to add new lock classes here, CXL_PORT_LOCK is > * extended by the port depth, so a maximum CXL port topology > - * depth would need to be defined first. > + * depth would need to be defined first. Also, the max > + * validation depth is limited by MAX_LOCKDEP_SUBCLASSES. > */ > }; > > +static inline int clamp_lock_class(struct device *dev, int lock_class) > +{ > + if (lock_class >= MAX_LOCKDEP_SUBCLASSES) { > + dev_warn_once(dev, > + "depth: %d, disabling lockdep for this device\n", > + lock_class); > + return 0; > + } > + > + return lock_class; > +} > + > static inline int cxl_lock_class(struct device *dev) > { > if (is_cxl_port(dev)) { > struct cxl_port *port = to_cxl_port(dev); > > - return CXL_PORT_LOCK + port->depth; > + return clamp_lock_class(dev, CXL_PORT_LOCK + port->depth); > } else if (is_cxl_decoder(dev)) { > struct cxl_port *port = to_cxl_port(dev->parent); > > @@ -522,7 +535,7 @@ static inline int cxl_lock_class(struct device *dev) > * A decoder is the immediate child of a port, so set > * its lock class equal to other child device siblings. > */ > - return CXL_PORT_LOCK + port->depth + 1; > + return clamp_lock_class(dev, CXL_PORT_LOCK + port->depth + 1); > } else if (is_cxl_nvdimm_bridge(dev)) > return CXL_NVDIMM_BRIDGE_LOCK; > else if (is_cxl_nvdimm(dev)) >
On Wed, Mar 9, 2022 at 10:27 AM Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote: > > On Mon, 28 Feb 2022 18:49:11 -0800 > Dan Williams <dan.j.williams@intel.com> wrote: > > > MAX_LOCKDEP_SUBCLASSES limits the depth of the CXL topology that can be > > validated by lockdep. Given that the cxl_test topology is already at > > this limit collapse some of the levels and clamp the max depth. > > > > Cc: Alison Schofield <alison.schofield@intel.com> > > Cc: Vishal Verma <vishal.l.verma@intel.com> > > Cc: Ira Weiny <ira.weiny@intel.com> > > Cc: Ben Widawsky <ben.widawsky@intel.com> > > Signed-off-by: Dan Williams <dan.j.williams@intel.com> > > --- > > drivers/cxl/cxl.h | 21 +++++++++++++++++---- > > 1 file changed, 17 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > > index 97e6ca7e4940..1357a245037d 100644 > > --- a/drivers/cxl/cxl.h > > +++ b/drivers/cxl/cxl.h > > @@ -501,20 +501,33 @@ enum cxl_lock_class { > > CXL_ANON_LOCK, > > CXL_NVDIMM_LOCK, > > CXL_NVDIMM_BRIDGE_LOCK, > > I'd be tempted to give explicit value to the one above as well > so it's immediate clear there is deliberate duplication here. Sounds good. I also notice that clamp_lock_class() should return -1 when it wants to disable validation, not zero.
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 97e6ca7e4940..1357a245037d 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -501,20 +501,33 @@ enum cxl_lock_class { CXL_ANON_LOCK, CXL_NVDIMM_LOCK, CXL_NVDIMM_BRIDGE_LOCK, - CXL_PORT_LOCK, + CXL_PORT_LOCK = 2, /* * Be careful to add new lock classes here, CXL_PORT_LOCK is * extended by the port depth, so a maximum CXL port topology - * depth would need to be defined first. + * depth would need to be defined first. Also, the max + * validation depth is limited by MAX_LOCKDEP_SUBCLASSES. */ }; +static inline int clamp_lock_class(struct device *dev, int lock_class) +{ + if (lock_class >= MAX_LOCKDEP_SUBCLASSES) { + dev_warn_once(dev, + "depth: %d, disabling lockdep for this device\n", + lock_class); + return 0; + } + + return lock_class; +} + static inline int cxl_lock_class(struct device *dev) { if (is_cxl_port(dev)) { struct cxl_port *port = to_cxl_port(dev); - return CXL_PORT_LOCK + port->depth; + return clamp_lock_class(dev, CXL_PORT_LOCK + port->depth); } else if (is_cxl_decoder(dev)) { struct cxl_port *port = to_cxl_port(dev->parent); @@ -522,7 +535,7 @@ static inline int cxl_lock_class(struct device *dev) * A decoder is the immediate child of a port, so set * its lock class equal to other child device siblings. */ - return CXL_PORT_LOCK + port->depth + 1; + return clamp_lock_class(dev, CXL_PORT_LOCK + port->depth + 1); } else if (is_cxl_nvdimm_bridge(dev)) return CXL_NVDIMM_BRIDGE_LOCK; else if (is_cxl_nvdimm(dev))
MAX_LOCKDEP_SUBCLASSES limits the depth of the CXL topology that can be validated by lockdep. Given that the cxl_test topology is already at this limit collapse some of the levels and clamp the max depth. Cc: Alison Schofield <alison.schofield@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Ben Widawsky <ben.widawsky@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- drivers/cxl/cxl.h | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)