Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Subject: [PATCH v2 06/12] cxl/core: Use dev->lock_class for device_lock()
 lockdep validation
From:   Dan Williams <dan.j.williams@intel.com>
To:     linux-cxl@vger.kernel.org
Cc:     Alison Schofield <alison.schofield@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Ben Widawsky <ben.widawsky@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Kevin Tian <kevin.tian@intel.com>, peterz@infradead.org,
        gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
        nvdimm@lists.linux.dev
Date:   Tue, 12 Apr 2022 23:02:00 -0700
Message-ID: <164982972055.684294.1452258386098745666.stgit@dwillia2-desk3.amr.corp.intel.com>
In-Reply-To: <164982968798.684294.15817853329823976469.stgit@dwillia2-desk3.amr.corp.intel.com>
References: <164982968798.684294.15817853329823976469.stgit@dwillia2-desk3.amr.corp.intel.com>
User-Agent: StGit/0.18-3-g996c
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Precedence: bulk

Update CONFIG_PROVE_CXL_LOCKING to use the common device-core helpers
for device_lock validation.

When CONFIG_PROVE_LOCKING is enabled, and device_set_lock_class() is
passed a non-zero lock class , the core acquires the 'struct device'
@lockdep_mutex everywhere it acquires the device_lock. Where
lockdep_mutex does not skip lockdep validation like device_lock.

cxl_set_lock_class() arranges to turn off CXL lock validation depending
on the value of CONFIG_PROVE_CXL_LOCKING, which is a Kconfig 'choice'
between the all subsystems that want to use dev->lockdep_mutex for
lockdep validation. For now, that 'choice' is just between the NVDIMM
and CXL subsystems.

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>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/core/memdev.c |    1 +
 drivers/cxl/core/pmem.c   |    2 ++
 drivers/cxl/core/port.c   |    2 ++
 drivers/cxl/cxl.h         |    9 +++++++++
 4 files changed, 14 insertions(+)

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 1f76b28f9826..ad8c9f61c38a 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -343,6 +343,7 @@ struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds)
 	cxlmd->cxlds = cxlds;
 
 	cdev = &cxlmd->cdev;
+	cxl_set_lock_class(dev);
 	rc = cdev_device_add(cdev, dev);
 	if (rc)
 		goto err;
diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c
index 60f71caa5dbd..b0eb0b795140 100644
--- a/drivers/cxl/core/pmem.c
+++ b/drivers/cxl/core/pmem.c
@@ -165,6 +165,7 @@ struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
 	if (rc)
 		goto err;
 
+	cxl_set_lock_class(dev);
 	rc = device_add(dev);
 	if (rc)
 		goto err;
@@ -261,6 +262,7 @@ int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd)
 	if (rc)
 		goto err;
 
+	cxl_set_lock_class(dev);
 	rc = device_add(dev);
 	if (rc)
 		goto err;
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 437e8a71e5dc..eb450397104b 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -469,6 +469,7 @@ struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
 	if (rc)
 		goto err;
 
+	cxl_set_lock_class(dev);
 	rc = device_add(dev);
 	if (rc)
 		goto err;
@@ -1349,6 +1350,7 @@ int cxl_decoder_add_locked(struct cxl_decoder *cxld, int *target_map)
 	if (is_root_decoder(dev))
 		cxld->platform_res.name = dev_name(dev);
 
+	cxl_set_lock_class(dev);
 	return device_add(dev);
 }
 EXPORT_SYMBOL_NS_GPL(cxl_decoder_add_locked, CXL);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index b86aac8cde4f..fddbcb380e84 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -456,5 +456,14 @@ static inline int cxl_lock_class(struct device *dev)
 	else
 		return CXL_ANON_LOCK;
 }
+
+static inline void cxl_set_lock_class(struct device *dev)
+{
+	device_set_lock_class(dev, cxl_lock_class(dev));
+}
+#else
+static inline void cxl_set_lock_class(struct device *dev)
+{
+}
 #endif
 #endif /* __CXL_H__ */