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dax: embed a struct device in dax_dev

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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: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2016-08-11 00:41:51 -07:00
parent af69f51e50
commit ebd84d724c
1 changed files with 45 additions and 85 deletions
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130
drivers/dax/dax.c
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@ -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) {
dev_dbg(dev, "%s\n", __func__);
filp->private_data = dax_dev;
kref_get(&dax_dev->kref);
inode->i_flags = S_DAX;
}
device_unlock(dev);
dax_dev = to_dax_dev(dev);
dev_dbg(dev, "%s\n", __func__);
filp->private_data = dax_dev;
inode->i_flags = S_DAX;
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;
}