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: Dan Williams <dan.j.williams@intel.com>hifive-unleashed-5.1
Dan Williams
parent
af69f51e50
commit
ebd84d724c
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@ -49,7 +49,6 @@ struct dax_region {
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* struct dax_dev - subdivision of a dax region
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* @region - parent region
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* @dev - device backing the character device
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* @kref - enable this data to be tracked in filp->private_data
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* @alive - !alive + rcu grace period == no new mappings can be established
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* @id - child id in the region
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* @num_resources - number of physical address extents in this device
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@ -57,8 +56,7 @@ struct dax_region {
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*/
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struct dax_dev {
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struct dax_region *region;
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struct device *dev;
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struct kref kref;
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struct device dev;
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bool alive;
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int id;
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int num_resources;
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@ -79,20 +77,6 @@ void dax_region_put(struct dax_region *dax_region)
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}
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EXPORT_SYMBOL_GPL(dax_region_put);
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static void dax_dev_free(struct kref *kref)
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{
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struct dax_dev *dax_dev;
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dax_dev = container_of(kref, struct dax_dev, kref);
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dax_region_put(dax_dev->region);
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kfree(dax_dev);
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}
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static void dax_dev_put(struct dax_dev *dax_dev)
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{
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kref_put(&dax_dev->kref, dax_dev_free);
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}
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struct dax_region *alloc_dax_region(struct device *parent, int region_id,
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struct resource *res, unsigned int align, void *addr,
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unsigned long pfn_flags)
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@ -117,10 +101,15 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
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}
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EXPORT_SYMBOL_GPL(alloc_dax_region);
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static struct dax_dev *to_dax_dev(struct device *dev)
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{
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return container_of(dev, struct dax_dev, dev);
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}
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static ssize_t size_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct dax_dev *dax_dev = dev_get_drvdata(dev);
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struct dax_dev *dax_dev = to_dax_dev(dev);
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unsigned long long size = 0;
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int i;
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@ -149,7 +138,7 @@ static int check_vma(struct dax_dev *dax_dev, struct vm_area_struct *vma,
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const char *func)
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{
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struct dax_region *dax_region = dax_dev->region;
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struct device *dev = dax_dev->dev;
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struct device *dev = &dax_dev->dev;
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unsigned long mask;
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if (!dax_dev->alive)
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@ -214,7 +203,7 @@ static int __dax_dev_fault(struct dax_dev *dax_dev, struct vm_area_struct *vma,
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struct vm_fault *vmf)
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{
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unsigned long vaddr = (unsigned long) vmf->virtual_address;
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struct device *dev = dax_dev->dev;
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struct device *dev = &dax_dev->dev;
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struct dax_region *dax_region;
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int rc = VM_FAULT_SIGBUS;
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phys_addr_t phys;
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@ -254,7 +243,7 @@ static int dax_dev_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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struct file *filp = vma->vm_file;
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struct dax_dev *dax_dev = filp->private_data;
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dev_dbg(dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,
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dev_dbg(&dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,
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current->comm, (vmf->flags & FAULT_FLAG_WRITE)
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? "write" : "read", vma->vm_start, vma->vm_end);
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rcu_read_lock();
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@ -269,7 +258,7 @@ static int __dax_dev_pmd_fault(struct dax_dev *dax_dev,
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unsigned int flags)
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{
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unsigned long pmd_addr = addr & PMD_MASK;
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struct device *dev = dax_dev->dev;
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struct device *dev = &dax_dev->dev;
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struct dax_region *dax_region;
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phys_addr_t phys;
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pgoff_t pgoff;
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@ -311,7 +300,7 @@ static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
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struct file *filp = vma->vm_file;
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struct dax_dev *dax_dev = filp->private_data;
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dev_dbg(dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,
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dev_dbg(&dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,
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current->comm, (flags & FAULT_FLAG_WRITE)
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? "write" : "read", vma->vm_start, vma->vm_end);
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@ -322,29 +311,9 @@ static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
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return rc;
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}
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static void dax_dev_vm_open(struct vm_area_struct *vma)
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{
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struct file *filp = vma->vm_file;
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struct dax_dev *dax_dev = filp->private_data;
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dev_dbg(dax_dev->dev, "%s\n", __func__);
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kref_get(&dax_dev->kref);
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}
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static void dax_dev_vm_close(struct vm_area_struct *vma)
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{
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struct file *filp = vma->vm_file;
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struct dax_dev *dax_dev = filp->private_data;
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dev_dbg(dax_dev->dev, "%s\n", __func__);
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dax_dev_put(dax_dev);
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}
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static const struct vm_operations_struct dax_dev_vm_ops = {
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.fault = dax_dev_fault,
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.pmd_fault = dax_dev_pmd_fault,
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.open = dax_dev_vm_open,
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.close = dax_dev_vm_close,
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};
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static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
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@ -352,13 +321,12 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
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struct dax_dev *dax_dev = filp->private_data;
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int rc;
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dev_dbg(dax_dev->dev, "%s\n", __func__);
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dev_dbg(&dax_dev->dev, "%s\n", __func__);
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rc = check_vma(dax_dev, vma, __func__);
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if (rc)
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return rc;
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kref_get(&dax_dev->kref);
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vma->vm_ops = &dax_dev_vm_ops;
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vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
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return 0;
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@ -420,30 +388,20 @@ static int dax_open(struct inode *inode, struct file *filp)
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if (!dev)
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return -ENXIO;
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device_lock(dev);
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dax_dev = dev_get_drvdata(dev);
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if (dax_dev) {
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dev_dbg(dev, "%s\n", __func__);
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filp->private_data = dax_dev;
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kref_get(&dax_dev->kref);
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inode->i_flags = S_DAX;
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}
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device_unlock(dev);
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dax_dev = to_dax_dev(dev);
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dev_dbg(dev, "%s\n", __func__);
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filp->private_data = dax_dev;
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inode->i_flags = S_DAX;
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if (!dax_dev) {
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put_device(dev);
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return -ENXIO;
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}
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return 0;
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}
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static int dax_release(struct inode *inode, struct file *filp)
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{
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struct dax_dev *dax_dev = filp->private_data;
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struct device *dev = dax_dev->dev;
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struct device *dev = &dax_dev->dev;
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dev_dbg(dax_dev->dev, "%s\n", __func__);
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dax_dev_put(dax_dev);
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dev_dbg(dev, "%s\n", __func__);
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put_device(dev);
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return 0;
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@ -458,12 +416,21 @@ static const struct file_operations dax_fops = {
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.mmap = dax_mmap,
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};
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static void unregister_dax_dev(void *_dev)
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static void dax_dev_release(struct device *dev)
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{
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struct device *dev = _dev;
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struct dax_dev *dax_dev = dev_get_drvdata(dev);
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struct dax_dev *dax_dev = to_dax_dev(dev);
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struct dax_region *dax_region = dax_dev->region;
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ida_simple_remove(&dax_region->ida, dax_dev->id);
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ida_simple_remove(&dax_minor_ida, MINOR(dev->devt));
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dax_region_put(dax_region);
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kfree(dax_dev);
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}
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static void unregister_dax_dev(void *dev)
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{
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struct dax_dev *dax_dev = to_dax_dev(dev);
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dev_dbg(dev, "%s\n", __func__);
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/*
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@ -475,13 +442,7 @@ static void unregister_dax_dev(void *_dev)
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*/
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dax_dev->alive = false;
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synchronize_rcu();
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get_device(dev);
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device_unregister(dev);
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ida_simple_remove(&dax_region->ida, dax_dev->id);
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ida_simple_remove(&dax_minor_ida, MINOR(dev->devt));
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put_device(dev);
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dax_dev_put(dax_dev);
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}
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int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res,
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@ -498,7 +459,6 @@ int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res,
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return -ENOMEM;
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memcpy(dax_dev->res, res, sizeof(*res) * count);
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dax_dev->num_resources = count;
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kref_init(&dax_dev->kref);
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dax_dev->alive = true;
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dax_dev->region = dax_region;
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kref_get(&dax_region->kref);
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@ -516,27 +476,27 @@ int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res,
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}
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dev_t = MKDEV(dax_major, minor);
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dev = device_create_with_groups(dax_class, parent, dev_t, dax_dev,
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dax_attribute_groups, "dax%d.%d", dax_region->id,
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dax_dev->id);
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if (IS_ERR(dev)) {
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rc = PTR_ERR(dev);
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goto err_create;
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}
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dax_dev->dev = dev;
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rc = devm_add_action_or_reset(dax_region->dev, unregister_dax_dev, dev);
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if (rc)
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dev = &dax_dev->dev;
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device_initialize(dev);
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dev->devt = dev_t;
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dev->class = dax_class;
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dev->parent = parent;
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dev->groups = dax_attribute_groups;
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dev->release = dax_dev_release;
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dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);
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rc = device_add(dev);
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if (rc) {
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put_device(dev);
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return rc;
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}
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return 0;
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return devm_add_action_or_reset(dax_region->dev, unregister_dax_dev, dev);
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err_create:
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ida_simple_remove(&dax_minor_ida, minor);
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err_minor:
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ida_simple_remove(&dax_region->ida, dax_dev->id);
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err_id:
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dax_dev_put(dax_dev);
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kfree(dax_dev);
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return rc;
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}
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