dax: store pfns in the radix
In preparation for examining the busy state of dax pages in the truncate path, switch from sectors to pfns in the radix. Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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6b2bb7265f
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3fe0791c29
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@ -124,10 +124,19 @@ int __bdev_dax_supported(struct super_block *sb, int blocksize)
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return len < 0 ? len : -EIO;
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}
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if ((IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn))
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|| pfn_t_devmap(pfn))
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if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) {
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/*
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* An arch that has enabled the pmem api should also
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* have its drivers support pfn_t_devmap()
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*
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* This is a developer warning and should not trigger in
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* production. dax_flush() will crash since it depends
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* on being able to do (page_address(pfn_to_page())).
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*/
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WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API));
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} else if (pfn_t_devmap(pfn)) {
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/* pass */;
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else {
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} else {
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pr_debug("VFS (%s): error: dax support not enabled\n",
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sb->s_id);
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return -EOPNOTSUPP;
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83
fs/dax.c
83
fs/dax.c
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@ -73,16 +73,15 @@ fs_initcall(init_dax_wait_table);
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#define RADIX_DAX_ZERO_PAGE (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
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#define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
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static unsigned long dax_radix_sector(void *entry)
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static unsigned long dax_radix_pfn(void *entry)
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{
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return (unsigned long)entry >> RADIX_DAX_SHIFT;
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}
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static void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
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static void *dax_radix_locked_entry(unsigned long pfn, unsigned long flags)
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{
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return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
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((unsigned long)sector << RADIX_DAX_SHIFT) |
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RADIX_DAX_ENTRY_LOCK);
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(pfn << RADIX_DAX_SHIFT) | RADIX_DAX_ENTRY_LOCK);
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}
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static unsigned int dax_radix_order(void *entry)
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@ -526,12 +525,13 @@ static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev,
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*/
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static void *dax_insert_mapping_entry(struct address_space *mapping,
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struct vm_fault *vmf,
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void *entry, sector_t sector,
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void *entry, pfn_t pfn_t,
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unsigned long flags, bool dirty)
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{
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struct radix_tree_root *page_tree = &mapping->page_tree;
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void *new_entry;
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unsigned long pfn = pfn_t_to_pfn(pfn_t);
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pgoff_t index = vmf->pgoff;
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void *new_entry;
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if (dirty)
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__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
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@ -546,7 +546,7 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
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}
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spin_lock_irq(&mapping->tree_lock);
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new_entry = dax_radix_locked_entry(sector, flags);
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new_entry = dax_radix_locked_entry(pfn, flags);
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if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
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/*
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@ -657,17 +657,14 @@ unlock_pte:
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i_mmap_unlock_read(mapping);
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}
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static int dax_writeback_one(struct block_device *bdev,
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struct dax_device *dax_dev, struct address_space *mapping,
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pgoff_t index, void *entry)
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static int dax_writeback_one(struct dax_device *dax_dev,
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struct address_space *mapping, pgoff_t index, void *entry)
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{
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struct radix_tree_root *page_tree = &mapping->page_tree;
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void *entry2, **slot, *kaddr;
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long ret = 0, id;
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sector_t sector;
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pgoff_t pgoff;
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void *entry2, **slot;
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unsigned long pfn;
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long ret = 0;
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size_t size;
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pfn_t pfn;
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/*
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* A page got tagged dirty in DAX mapping? Something is seriously
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@ -683,10 +680,10 @@ static int dax_writeback_one(struct block_device *bdev,
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goto put_unlocked;
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/*
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* Entry got reallocated elsewhere? No need to writeback. We have to
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* compare sectors as we must not bail out due to difference in lockbit
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* compare pfns as we must not bail out due to difference in lockbit
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* or entry type.
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*/
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if (dax_radix_sector(entry2) != dax_radix_sector(entry))
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if (dax_radix_pfn(entry2) != dax_radix_pfn(entry))
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goto put_unlocked;
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if (WARN_ON_ONCE(dax_is_empty_entry(entry) ||
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dax_is_zero_entry(entry))) {
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@ -712,33 +709,15 @@ static int dax_writeback_one(struct block_device *bdev,
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/*
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* Even if dax_writeback_mapping_range() was given a wbc->range_start
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* in the middle of a PMD, the 'index' we are given will be aligned to
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* the start index of the PMD, as will the sector we pull from
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* 'entry'. This allows us to flush for PMD_SIZE and not have to
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* worry about partial PMD writebacks.
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* the start index of the PMD, as will the pfn we pull from 'entry'.
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* This allows us to flush for PMD_SIZE and not have to worry about
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* partial PMD writebacks.
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*/
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sector = dax_radix_sector(entry);
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pfn = dax_radix_pfn(entry);
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size = PAGE_SIZE << dax_radix_order(entry);
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id = dax_read_lock();
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ret = bdev_dax_pgoff(bdev, sector, size, &pgoff);
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if (ret)
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goto dax_unlock;
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/*
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* dax_direct_access() may sleep, so cannot hold tree_lock over
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* its invocation.
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*/
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ret = dax_direct_access(dax_dev, pgoff, size / PAGE_SIZE, &kaddr, &pfn);
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if (ret < 0)
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goto dax_unlock;
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if (WARN_ON_ONCE(ret < size / PAGE_SIZE)) {
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ret = -EIO;
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goto dax_unlock;
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}
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dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(pfn));
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dax_flush(dax_dev, kaddr, size);
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dax_mapping_entry_mkclean(mapping, index, pfn);
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dax_flush(dax_dev, page_address(pfn_to_page(pfn)), size);
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/*
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* After we have flushed the cache, we can clear the dirty tag. There
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* cannot be new dirty data in the pfn after the flush has completed as
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@ -749,8 +728,6 @@ static int dax_writeback_one(struct block_device *bdev,
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radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY);
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spin_unlock_irq(&mapping->tree_lock);
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trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT);
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dax_unlock:
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dax_read_unlock(id);
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put_locked_mapping_entry(mapping, index);
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return ret;
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@ -808,8 +785,8 @@ int dax_writeback_mapping_range(struct address_space *mapping,
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break;
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}
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ret = dax_writeback_one(bdev, dax_dev, mapping,
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indices[i], pvec.pages[i]);
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ret = dax_writeback_one(dax_dev, mapping, indices[i],
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pvec.pages[i]);
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if (ret < 0) {
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mapping_set_error(mapping, ret);
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goto out;
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@ -877,6 +854,7 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
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int ret = VM_FAULT_NOPAGE;
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struct page *zero_page;
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void *entry2;
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pfn_t pfn;
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zero_page = ZERO_PAGE(0);
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if (unlikely(!zero_page)) {
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@ -884,14 +862,15 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
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goto out;
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}
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entry2 = dax_insert_mapping_entry(mapping, vmf, entry, 0,
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pfn = page_to_pfn_t(zero_page);
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entry2 = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
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RADIX_DAX_ZERO_PAGE, false);
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if (IS_ERR(entry2)) {
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ret = VM_FAULT_SIGBUS;
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goto out;
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}
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vm_insert_mixed(vmf->vma, vaddr, page_to_pfn_t(zero_page));
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vm_insert_mixed(vmf->vma, vaddr, pfn);
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out:
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trace_dax_load_hole(inode, vmf, ret);
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return ret;
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@ -1200,8 +1179,7 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
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if (error < 0)
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goto error_finish_iomap;
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entry = dax_insert_mapping_entry(mapping, vmf, entry,
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dax_iomap_sector(&iomap, pos),
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entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
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0, write && !sync);
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if (IS_ERR(entry)) {
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error = PTR_ERR(entry);
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@ -1280,13 +1258,15 @@ static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
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void *ret = NULL;
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spinlock_t *ptl;
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pmd_t pmd_entry;
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pfn_t pfn;
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zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm);
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if (unlikely(!zero_page))
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goto fallback;
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ret = dax_insert_mapping_entry(mapping, vmf, entry, 0,
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pfn = page_to_pfn_t(zero_page);
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ret = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
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RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE, false);
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if (IS_ERR(ret))
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goto fallback;
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@ -1409,8 +1389,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
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if (error < 0)
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goto finish_iomap;
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entry = dax_insert_mapping_entry(mapping, vmf, entry,
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dax_iomap_sector(&iomap, pos),
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entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
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RADIX_DAX_PMD, write && !sync);
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if (IS_ERR(entry))
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goto finish_iomap;
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