[PATCH v2 04/12] cxl/core: Remove cxl_device_lock()

From: Dan Williams
Date: Wed Apr 13 2022 - 02:02:42 EST

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In preparation for moving lockdep_mutex nested lock acquisition into the
core, remove the cxl_device_lock() wrapper, but preserve
cxl_lock_class() that will be used to inform the core of the subsystem's
lock ordering rules.

Note that this reverts back to the default state of unvalidated
device_lock(). A follow-on change to use the new dev->lock_class
facility re-enables lockdep validation.

Cc: Alison Schofield <alison.schofield@xxxxxxxxx>
Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Ben Widawsky <ben.widawsky@xxxxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/cxl/core/pmem.c | 4 ++-
drivers/cxl/core/port.c | 54 ++++++++++++++++++++---------------------------
drivers/cxl/cxl.h | 46 ----------------------------------------
drivers/cxl/mem.c | 4 ++-
drivers/cxl/pmem.c | 12 +++++-----
lib/Kconfig.debug | 2 +-
6 files changed, 34 insertions(+), 88 deletions(-)

diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c
index 8de240c4d96b..60f71caa5dbd 100644
--- a/drivers/cxl/core/pmem.c
+++ b/drivers/cxl/core/pmem.c
@@ -121,10 +121,10 @@ static void unregister_nvb(void *_cxl_nvb)
* work to flush. Once the state has been changed to 'dead' then no new
* work can be queued by user-triggered bind.
*/
- cxl_device_lock(&cxl_nvb->dev);
+ device_lock(&cxl_nvb->dev);
flush = cxl_nvb->state != CXL_NVB_NEW;
cxl_nvb->state = CXL_NVB_DEAD;
- cxl_device_unlock(&cxl_nvb->dev);
+ device_unlock(&cxl_nvb->dev);

/*
* Even though the device core will trigger device_release_driver()
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 2ab1ba4499b3..437e8a71e5dc 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -312,10 +312,10 @@ static void cxl_port_release(struct device *dev)
struct cxl_port *port = to_cxl_port(dev);
struct cxl_ep *ep, *_e;

- cxl_device_lock(dev);
+ device_lock(dev);
list_for_each_entry_safe(ep, _e, &port->endpoints, list)
cxl_ep_release(ep);
- cxl_device_unlock(dev);
+ device_unlock(dev);
ida_free(&cxl_port_ida, port->id);
kfree(port);
}
@@ -554,7 +554,7 @@ static int match_root_child(struct device *dev, const void *match)
return 0;

port = to_cxl_port(dev);
- cxl_device_lock(dev);
+ device_lock(dev);
list_for_each_entry(dport, &port->dports, list) {
iter = match;
while (iter) {
@@ -564,7 +564,7 @@ static int match_root_child(struct device *dev, const void *match)
}
}
out:
- cxl_device_unlock(dev);
+ device_unlock(dev);

return !!iter;
}
@@ -623,13 +623,13 @@ static int add_dport(struct cxl_port *port, struct cxl_dport *new)
static void cond_cxl_root_lock(struct cxl_port *port)
{
if (is_cxl_root(port))
- cxl_device_lock(&port->dev);
+ device_lock(&port->dev);
}

static void cond_cxl_root_unlock(struct cxl_port *port)
{
if (is_cxl_root(port))
- cxl_device_unlock(&port->dev);
+ device_unlock(&port->dev);
}

static void cxl_dport_remove(void *data)
@@ -736,15 +736,15 @@ static int add_ep(struct cxl_port *port, struct cxl_ep *new)
{
struct cxl_ep *dup;

- cxl_device_lock(&port->dev);
+ device_lock(&port->dev);
if (port->dead) {
- cxl_device_unlock(&port->dev);
+ device_unlock(&port->dev);
return -ENXIO;
}
dup = find_ep(port, new->ep);
if (!dup)
list_add_tail(&new->list, &port->endpoints);
- cxl_device_unlock(&port->dev);
+ device_unlock(&port->dev);

return dup ? -EEXIST : 0;
}
@@ -854,12 +854,12 @@ static void delete_endpoint(void *data)
goto out;
parent = &parent_port->dev;

- cxl_device_lock(parent);
+ device_lock(parent);
if (parent->driver && endpoint->uport) {
devm_release_action(parent, cxl_unlink_uport, endpoint);
devm_release_action(parent, unregister_port, endpoint);
}
- cxl_device_unlock(parent);
+ device_unlock(parent);
put_device(parent);
out:
put_device(&endpoint->dev);
@@ -920,7 +920,7 @@ static void cxl_detach_ep(void *data)
}

parent_port = to_cxl_port(port->dev.parent);
- cxl_device_lock(&parent_port->dev);
+ device_lock(&parent_port->dev);
if (!parent_port->dev.driver) {
/*
* The bottom-up race to delete the port lost to a
@@ -928,12 +928,12 @@ static void cxl_detach_ep(void *data)
* parent_port ->remove() will have cleaned up all
* descendants.
*/
- cxl_device_unlock(&parent_port->dev);
+ device_unlock(&parent_port->dev);
put_device(&port->dev);
continue;
}

- cxl_device_lock(&port->dev);
+ device_lock(&port->dev);
ep = find_ep(port, &cxlmd->dev);
dev_dbg(&cxlmd->dev, "disconnect %s from %s\n",
ep ? dev_name(ep->ep) : "", dev_name(&port->dev));
@@ -948,7 +948,7 @@ static void cxl_detach_ep(void *data)
port->dead = true;
list_splice_init(&port->dports, &reap_dports);
}
- cxl_device_unlock(&port->dev);
+ device_unlock(&port->dev);

if (!list_empty(&reap_dports)) {
dev_dbg(&cxlmd->dev, "delete %s\n",
@@ -956,7 +956,7 @@ static void cxl_detach_ep(void *data)
delete_switch_port(port, &reap_dports);
}
put_device(&port->dev);
- cxl_device_unlock(&parent_port->dev);
+ device_unlock(&parent_port->dev);
}
}

@@ -1004,7 +1004,7 @@ static int add_port_attach_ep(struct cxl_memdev *cxlmd,
return -EAGAIN;
}

- cxl_device_lock(&parent_port->dev);
+ device_lock(&parent_port->dev);
if (!parent_port->dev.driver) {
dev_warn(&cxlmd->dev,
"port %s:%s disabled, failed to enumerate CXL.mem\n",
@@ -1022,7 +1022,7 @@ static int add_port_attach_ep(struct cxl_memdev *cxlmd,
get_device(&port->dev);
}
out:
- cxl_device_unlock(&parent_port->dev);
+ device_unlock(&parent_port->dev);

if (IS_ERR(port))
rc = PTR_ERR(port);
@@ -1133,14 +1133,14 @@ struct cxl_dport *cxl_find_dport_by_dev(struct cxl_port *port,
{
struct cxl_dport *dport;

- cxl_device_lock(&port->dev);
+ device_lock(&port->dev);
list_for_each_entry(dport, &port->dports, list)
if (dport->dport == dev) {
- cxl_device_unlock(&port->dev);
+ device_unlock(&port->dev);
return dport;
}

- cxl_device_unlock(&port->dev);
+ device_unlock(&port->dev);
return NULL;
}
EXPORT_SYMBOL_NS_GPL(cxl_find_dport_by_dev, CXL);
@@ -1379,9 +1379,9 @@ int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map)

port = to_cxl_port(cxld->dev.parent);

- cxl_device_lock(&port->dev);
+ device_lock(&port->dev);
rc = cxl_decoder_add_locked(cxld, target_map);
- cxl_device_unlock(&port->dev);
+ device_unlock(&port->dev);

return rc;
}
@@ -1452,13 +1452,7 @@ static int cxl_bus_probe(struct device *dev)
{
int rc;

- /*
- * Take the CXL nested lock since the driver core only holds
- * @dev->mutex and not @dev->lockdep_mutex.
- */
- cxl_nested_lock(dev);
rc = to_cxl_drv(dev->driver)->probe(dev);
- cxl_nested_unlock(dev);

dev_dbg(dev, "probe: %d\n", rc);
return rc;
@@ -1468,10 +1462,8 @@ static void cxl_bus_remove(struct device *dev)
{
struct cxl_driver *cxl_drv = to_cxl_drv(dev->driver);

- cxl_nested_lock(dev);
if (cxl_drv->remove)
cxl_drv->remove(dev);
- cxl_nested_unlock(dev);
}

static struct workqueue_struct *cxl_bus_wq;
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index c9fda9304c54..a6c1a027e389 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -439,51 +439,5 @@ static inline int cxl_lock_class(struct device *dev)
else
return CXL_ANON_LOCK;
}
-
-static inline void cxl_nested_lock(struct device *dev)
-{
- mutex_lock_nested(&dev->lockdep_mutex, cxl_lock_class(dev));
-}
-
-static inline void cxl_nested_unlock(struct device *dev)
-{
- mutex_unlock(&dev->lockdep_mutex);
-}
-
-static inline void cxl_device_lock(struct device *dev)
-{
- /*
- * For double lock errors the lockup will happen before lockdep
- * warns at cxl_nested_lock(), so assert explicitly.
- */
- lockdep_assert_not_held(&dev->lockdep_mutex);
-
- device_lock(dev);
- cxl_nested_lock(dev);
-}
-
-static inline void cxl_device_unlock(struct device *dev)
-{
- cxl_nested_unlock(dev);
- device_unlock(dev);
-}
-#else
-static inline void cxl_nested_lock(struct device *dev)
-{
-}
-
-static inline void cxl_nested_unlock(struct device *dev)
-{
-}
-
-static inline void cxl_device_lock(struct device *dev)
-{
- device_lock(dev);
-}
-
-static inline void cxl_device_unlock(struct device *dev)
-{
- device_unlock(dev);
-}
#endif
#endif /* __CXL_H__ */
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 49a4b1c47299..91fb8d5b21a7 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -195,7 +195,7 @@ static int cxl_mem_probe(struct device *dev)
return -ENXIO;
}

- cxl_device_lock(&parent_port->dev);
+ device_lock(&parent_port->dev);
if (!parent_port->dev.driver) {
dev_err(dev, "CXL port topology %s not enabled\n",
dev_name(&parent_port->dev));
@@ -205,7 +205,7 @@ static int cxl_mem_probe(struct device *dev)

rc = create_endpoint(cxlmd, parent_port);
out:
- cxl_device_unlock(&parent_port->dev);
+ device_unlock(&parent_port->dev);
put_device(&parent_port->dev);
return rc;
}
diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
index 15ad666ab03e..b65a272a2d6d 100644
--- a/drivers/cxl/pmem.c
+++ b/drivers/cxl/pmem.c
@@ -43,7 +43,7 @@ static int cxl_nvdimm_probe(struct device *dev)
if (!cxl_nvb)
return -ENXIO;

- cxl_device_lock(&cxl_nvb->dev);
+ device_lock(&cxl_nvb->dev);
if (!cxl_nvb->nvdimm_bus) {
rc = -ENXIO;
goto out;
@@ -68,7 +68,7 @@ static int cxl_nvdimm_probe(struct device *dev)
dev_set_drvdata(dev, nvdimm);
rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm);
out:
- cxl_device_unlock(&cxl_nvb->dev);
+ device_unlock(&cxl_nvb->dev);
put_device(&cxl_nvb->dev);

return rc;
@@ -233,7 +233,7 @@ static void cxl_nvb_update_state(struct work_struct *work)
struct nvdimm_bus *victim_bus = NULL;
bool release = false, rescan = false;

- cxl_device_lock(&cxl_nvb->dev);
+ device_lock(&cxl_nvb->dev);
switch (cxl_nvb->state) {
case CXL_NVB_ONLINE:
if (!online_nvdimm_bus(cxl_nvb)) {
@@ -251,7 +251,7 @@ static void cxl_nvb_update_state(struct work_struct *work)
default:
break;
}
- cxl_device_unlock(&cxl_nvb->dev);
+ device_unlock(&cxl_nvb->dev);

if (release)
device_release_driver(&cxl_nvb->dev);
@@ -327,9 +327,9 @@ static int cxl_nvdimm_bridge_reset(struct device *dev, void *data)
return 0;

cxl_nvb = to_cxl_nvdimm_bridge(dev);
- cxl_device_lock(dev);
+ device_lock(dev);
cxl_nvb->state = CXL_NVB_NEW;
- cxl_device_unlock(dev);
+ device_unlock(dev);

return 0;
}
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 075cd25363ac..333d41da7621 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1563,7 +1563,7 @@ config PROVE_CXL_LOCKING
bool "CXL"
depends on CXL_BUS
help
- Enable lockdep to validate cxl_device_lock() usage.
+ Enable lockdep to validate CXL subsystem usage of the device lock.

endchoice

Next message: Dan Williams: "[PATCH v2 10/12] libnvdimm: Drop nd_device_lock()"
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In reply to: Dan Williams: "[PATCH v2 09/12] ACPI: NFIT: Drop nfit_device_lock()"
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