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Subject: [PATCH v6 05/11] device-dax: introduce 'struct dev_dax'
 typed-driver operations
From:   Dan Williams <dan.j.williams@intel.com>
To:     akpm@linux-foundation.org
Cc:     Jason Yan <yanaijie@huawei.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Brice Goglin <Brice.Goglin@inria.fr>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        David Hildenbrand <david@redhat.com>,
        Ira Weiny <ira.weiny@intel.com>, Jia He <justin.he@arm.com>,
        Joao Martins <joao.m.martins@oracle.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Hulk Robot <hulkci@huawei.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org,
        david@redhat.com, joao.m.martins@oracle.com
Date:   Mon, 05 Oct 2020 23:55:12 -0700
Message-ID: <160196731254.2166475.15779124872548332662.stgit@dwillia2-desk3.amr.corp.intel.com>
In-Reply-To: <160196728453.2166475.12832711415715687418.stgit@dwillia2-desk3.amr.corp.intel.com>
References: <160196728453.2166475.12832711415715687418.stgit@dwillia2-desk3.amr.corp.intel.com>
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In preparation for introducing seed devices the dax-bus core needs to be
able to intercept ->probe() and ->remove() operations. Towards that end
arrange for the bus and drivers to switch from raw 'struct device'
driver operations to 'struct dev_dax' typed operations.

Cc: Jason Yan <yanaijie@huawei.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jia He <justin.he@arm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/dax/bus.c         |   18 ++++++++++++++++++
 drivers/dax/bus.h         |    4 +++-
 drivers/dax/device.c      |   12 +++++-------
 drivers/dax/kmem.c        |   18 ++++++++----------
 drivers/dax/pmem/compat.c |    2 +-
 5 files changed, 35 insertions(+), 19 deletions(-)

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 0a48ce378686..9549f11ebed0 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -135,10 +135,28 @@ static bool is_static(struct dax_region *dax_region)
 	return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0;
 }
 
+static int dax_bus_probe(struct device *dev)
+{
+	struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
+	struct dev_dax *dev_dax = to_dev_dax(dev);
+
+	return dax_drv->probe(dev_dax);
+}
+
+static int dax_bus_remove(struct device *dev)
+{
+	struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
+	struct dev_dax *dev_dax = to_dev_dax(dev);
+
+	return dax_drv->remove(dev_dax);
+}
+
 static struct bus_type dax_bus_type = {
 	.name = "dax",
 	.uevent = dax_bus_uevent,
 	.match = dax_bus_match,
+	.probe = dax_bus_probe,
+	.remove = dax_bus_remove,
 	.drv_groups = dax_drv_groups,
 };
 
diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
index 44592a8cac0f..da27ea70a19a 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -38,6 +38,8 @@ struct dax_device_driver {
 	struct device_driver drv;
 	struct list_head ids;
 	int match_always;
+	int (*probe)(struct dev_dax *dev);
+	int (*remove)(struct dev_dax *dev);
 };
 
 int __dax_driver_register(struct dax_device_driver *dax_drv,
@@ -48,7 +50,7 @@ void dax_driver_unregister(struct dax_device_driver *dax_drv);
 void kill_dev_dax(struct dev_dax *dev_dax);
 
 #if IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)
-int dev_dax_probe(struct device *dev);
+int dev_dax_probe(struct dev_dax *dev_dax);
 #endif
 
 /*
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 287cf0a3db23..9833fa83b537 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -392,11 +392,11 @@ static void dev_dax_kill(void *dev_dax)
 	kill_dev_dax(dev_dax);
 }
 
-int dev_dax_probe(struct device *dev)
+int dev_dax_probe(struct dev_dax *dev_dax)
 {
-	struct dev_dax *dev_dax = to_dev_dax(dev);
 	struct dax_device *dax_dev = dev_dax->dax_dev;
 	struct range *range = &dev_dax->range;
+	struct device *dev = &dev_dax->dev;
 	struct dev_pagemap *pgmap;
 	struct inode *inode;
 	struct cdev *cdev;
@@ -446,17 +446,15 @@ int dev_dax_probe(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_dax_probe);
 
-static int dev_dax_remove(struct device *dev)
+static int dev_dax_remove(struct dev_dax *dev_dax)
 {
 	/* all probe actions are unwound by devm */
 	return 0;
 }
 
 static struct dax_device_driver device_dax_driver = {
-	.drv = {
-		.probe = dev_dax_probe,
-		.remove = dev_dax_remove,
-	},
+	.probe = dev_dax_probe,
+	.remove = dev_dax_remove,
 	.match_always = 1,
 };
 
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index a415bc239db4..5fb27fd3eb61 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -34,10 +34,10 @@ struct dax_kmem_data {
 	struct resource *res;
 };
 
-int dev_dax_kmem_probe(struct device *dev)
+static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
 {
-	struct dev_dax *dev_dax = to_dev_dax(dev);
 	struct range range = dax_kmem_range(dev_dax);
+	struct device *dev = &dev_dax->dev;
 	struct dax_kmem_data *data;
 	struct resource *new_res;
 	int rc = -ENOMEM;
@@ -105,12 +105,12 @@ int dev_dax_kmem_probe(struct device *dev)
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-static int dev_dax_kmem_remove(struct device *dev)
+static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
 {
-	struct dev_dax *dev_dax = to_dev_dax(dev);
+	int rc;
+	struct device *dev = &dev_dax->dev;
 	struct range range = dax_kmem_range(dev_dax);
 	struct dax_kmem_data *data = dev_get_drvdata(dev);
-	int rc;
 
 	/*
 	 * We have one shot for removing memory, if some memory blocks were not
@@ -135,7 +135,7 @@ static int dev_dax_kmem_remove(struct device *dev)
 	return 0;
 }
 #else
-static int dev_dax_kmem_remove(struct device *dev)
+static int dev_dax_kmem_remove(struct dev_dax *dev_dax)
 {
 	/*
 	 * Without hotremove purposely leak the request_mem_region() for the
@@ -150,10 +150,8 @@ static int dev_dax_kmem_remove(struct device *dev)
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
 static struct dax_device_driver device_dax_kmem_driver = {
-	.drv = {
-		.probe = dev_dax_kmem_probe,
-		.remove = dev_dax_kmem_remove,
-	},
+	.probe = dev_dax_kmem_probe,
+	.remove = dev_dax_kmem_remove,
 };
 
 static int __init dax_kmem_init(void)
diff --git a/drivers/dax/pmem/compat.c b/drivers/dax/pmem/compat.c
index d7b15e6f30c5..863c114fd88c 100644
--- a/drivers/dax/pmem/compat.c
+++ b/drivers/dax/pmem/compat.c
@@ -22,7 +22,7 @@ static int dax_pmem_compat_probe(struct device *dev)
 		return -ENOMEM;
 
 	device_lock(&dev_dax->dev);
-	rc = dev_dax_probe(&dev_dax->dev);
+	rc = dev_dax_probe(dev_dax);
 	device_unlock(&dev_dax->dev);
 
 	devres_close_group(&dev_dax->dev, dev_dax);