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Commit ebd84d72 authored by Dan Williams's avatar Dan Williams
Browse files

dax: embed a struct device in dax_dev 



The kref in dax_dev can be made redundant if the final put_device() on
the device associated with the dax_dev frees the dax_dev.  This can be
accomplished by embedding a struct device in struct dax_dev, open coding
device_create() and specifying a custom release method.

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent af69f51e

drivers/dax/dax.c

+45 −85
Original line number Diff line number Diff line
@@ -49,7 +49,6 @@ struct dax_region { 
 * struct dax_dev - subdivision of a dax region

 * @region - parent region

 * @dev - device backing the character device

 * @kref - enable this data to be tracked in filp->private_data

 * @alive - !alive + rcu grace period == no new mappings can be established

 * @id - child id in the region

 * @num_resources - number of physical address extents in this device
@@ -57,8 +56,7 @@ struct dax_region { 
 */

struct dax_dev {

	struct dax_region *region;

	struct device *dev;

	struct kref kref;

	struct device dev;

	bool alive;

	int id;

	int num_resources;
@@ -79,20 +77,6 @@ void dax_region_put(struct dax_region *dax_region) 
}

EXPORT_SYMBOL_GPL(dax_region_put);



static void dax_dev_free(struct kref *kref)

{

	struct dax_dev *dax_dev;



	dax_dev = container_of(kref, struct dax_dev, kref);

	dax_region_put(dax_dev->region);

	kfree(dax_dev);

}



static void dax_dev_put(struct dax_dev *dax_dev)

{

	kref_put(&dax_dev->kref, dax_dev_free);

}



struct dax_region *alloc_dax_region(struct device *parent, int region_id,

		struct resource *res, unsigned int align, void *addr,

		unsigned long pfn_flags)
@@ -117,10 +101,15 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id, 
}

EXPORT_SYMBOL_GPL(alloc_dax_region);



static struct dax_dev *to_dax_dev(struct device *dev)

{

	return container_of(dev, struct dax_dev, dev);

}



static ssize_t size_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct dax_dev *dax_dev = dev_get_drvdata(dev);

	struct dax_dev *dax_dev = to_dax_dev(dev);

	unsigned long long size = 0;

	int i;
@@ -149,7 +138,7 @@ static int check_vma(struct dax_dev *dax_dev, struct vm_area_struct *vma, 
		const char *func)

{

	struct dax_region *dax_region = dax_dev->region;

	struct device *dev = dax_dev->dev;

	struct device *dev = &dax_dev->dev;

	unsigned long mask;



	if (!dax_dev->alive)
@@ -214,7 +203,7 @@ static int __dax_dev_fault(struct dax_dev *dax_dev, struct vm_area_struct *vma, 
		struct vm_fault *vmf)

{

	unsigned long vaddr = (unsigned long) vmf->virtual_address;

	struct device *dev = dax_dev->dev;

	struct device *dev = &dax_dev->dev;

	struct dax_region *dax_region;

	int rc = VM_FAULT_SIGBUS;

	phys_addr_t phys;
@@ -254,7 +243,7 @@ static int dax_dev_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 
	struct file *filp = vma->vm_file;

	struct dax_dev *dax_dev = filp->private_data;



	dev_dbg(dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,

	dev_dbg(&dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,

			current->comm, (vmf->flags & FAULT_FLAG_WRITE)

			? "write" : "read", vma->vm_start, vma->vm_end);

	rcu_read_lock();
@@ -269,7 +258,7 @@ static int __dax_dev_pmd_fault(struct dax_dev *dax_dev, 
		unsigned int flags)

{

	unsigned long pmd_addr = addr & PMD_MASK;

	struct device *dev = dax_dev->dev;

	struct device *dev = &dax_dev->dev;

	struct dax_region *dax_region;

	phys_addr_t phys;

	pgoff_t pgoff;
@@ -311,7 +300,7 @@ static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr, 
	struct file *filp = vma->vm_file;

	struct dax_dev *dax_dev = filp->private_data;



	dev_dbg(dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,

	dev_dbg(&dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,

			current->comm, (flags & FAULT_FLAG_WRITE)

			? "write" : "read", vma->vm_start, vma->vm_end);
@@ -322,29 +311,9 @@ static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr, 
	return rc;

}



static void dax_dev_vm_open(struct vm_area_struct *vma)

{

	struct file *filp = vma->vm_file;

	struct dax_dev *dax_dev = filp->private_data;



	dev_dbg(dax_dev->dev, "%s\n", __func__);

	kref_get(&dax_dev->kref);

}



static void dax_dev_vm_close(struct vm_area_struct *vma)

{

	struct file *filp = vma->vm_file;

	struct dax_dev *dax_dev = filp->private_data;



	dev_dbg(dax_dev->dev, "%s\n", __func__);

	dax_dev_put(dax_dev);

}



static const struct vm_operations_struct dax_dev_vm_ops = {

	.fault = dax_dev_fault,

	.pmd_fault = dax_dev_pmd_fault,

	.open = dax_dev_vm_open,

	.close = dax_dev_vm_close,

};



static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
@@ -352,13 +321,12 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma) 
	struct dax_dev *dax_dev = filp->private_data;

	int rc;



	dev_dbg(dax_dev->dev, "%s\n", __func__);

	dev_dbg(&dax_dev->dev, "%s\n", __func__);



	rc = check_vma(dax_dev, vma, __func__);

	if (rc)

		return rc;



	kref_get(&dax_dev->kref);

	vma->vm_ops = &dax_dev_vm_ops;

	vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;

	return 0;
@@ -420,30 +388,20 @@ static int dax_open(struct inode *inode, struct file *filp) 
	if (!dev)

		return -ENXIO;



	device_lock(dev);

	dax_dev = dev_get_drvdata(dev);

	if (dax_dev) {

	dax_dev = to_dax_dev(dev);

	dev_dbg(dev, "%s\n", __func__);

	filp->private_data = dax_dev;

		kref_get(&dax_dev->kref);

	inode->i_flags = S_DAX;

	}

	device_unlock(dev);



	if (!dax_dev) {

		put_device(dev);

		return -ENXIO;

	}

	return 0;

}



static int dax_release(struct inode *inode, struct file *filp)

{

	struct dax_dev *dax_dev = filp->private_data;

	struct device *dev = dax_dev->dev;

	struct device *dev = &dax_dev->dev;



	dev_dbg(dax_dev->dev, "%s\n", __func__);

	dax_dev_put(dax_dev);

	dev_dbg(dev, "%s\n", __func__);

	put_device(dev);



	return 0;
@@ -458,12 +416,21 @@ static const struct file_operations dax_fops = { 
	.mmap = dax_mmap,

};



static void unregister_dax_dev(void *_dev)

static void dax_dev_release(struct device *dev)

{

	struct device *dev = _dev;

	struct dax_dev *dax_dev = dev_get_drvdata(dev);

	struct dax_dev *dax_dev = to_dax_dev(dev);

	struct dax_region *dax_region = dax_dev->region;



	ida_simple_remove(&dax_region->ida, dax_dev->id);

	ida_simple_remove(&dax_minor_ida, MINOR(dev->devt));

	dax_region_put(dax_region);

	kfree(dax_dev);

}



static void unregister_dax_dev(void *dev)

{

	struct dax_dev *dax_dev = to_dax_dev(dev);



	dev_dbg(dev, "%s\n", __func__);



	/*
@@ -475,13 +442,7 @@ static void unregister_dax_dev(void *_dev) 
	 */

	dax_dev->alive = false;

	synchronize_rcu();



	get_device(dev);

	device_unregister(dev);

	ida_simple_remove(&dax_region->ida, dax_dev->id);

	ida_simple_remove(&dax_minor_ida, MINOR(dev->devt));

	put_device(dev);

	dax_dev_put(dax_dev);

}



int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res,
@@ -498,7 +459,6 @@ int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res, 
		return -ENOMEM;

	memcpy(dax_dev->res, res, sizeof(*res) * count);

	dax_dev->num_resources = count;

	kref_init(&dax_dev->kref);

	dax_dev->alive = true;

	dax_dev->region = dax_region;

	kref_get(&dax_region->kref);
@@ -516,27 +476,27 @@ int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res, 
	}



	dev_t = MKDEV(dax_major, minor);

	dev = device_create_with_groups(dax_class, parent, dev_t, dax_dev,

			dax_attribute_groups, "dax%d.%d", dax_region->id,

			dax_dev->id);

	if (IS_ERR(dev)) {

		rc = PTR_ERR(dev);

		goto err_create;

	}

	dax_dev->dev = dev;



	rc = devm_add_action_or_reset(dax_region->dev, unregister_dax_dev, dev);

	if (rc)

	dev = &dax_dev->dev;

	device_initialize(dev);

	dev->devt = dev_t;

	dev->class = dax_class;

	dev->parent = parent;

	dev->groups = dax_attribute_groups;

	dev->release = dax_dev_release;

	dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);

	rc = device_add(dev);

	if (rc) {

		put_device(dev);

		return rc;

	}



	return 0;

	return devm_add_action_or_reset(dax_region->dev, unregister_dax_dev, dev);



 err_create:

	ida_simple_remove(&dax_minor_ida, minor);

 err_minor:

	ida_simple_remove(&dax_region->ida, dax_dev->id);

 err_id:

	dax_dev_put(dax_dev);

	kfree(dax_dev);



	return rc;

}