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478a1469a7
- We use a bit in an exceptional radix tree entry as a lock bit and use it
similarly to how page lock is used for normal faults. This fixes races
between hole instantiation and read faults of the same index.
- Filesystem DAX PMD faults are disabled, and will be re-enabled when PMD
locking is implemented.
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Merge tag 'dax-locking-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull DAX locking updates from Ross Zwisler:
"Filesystem DAX locking for 4.7
- We use a bit in an exceptional radix tree entry as a lock bit and
use it similarly to how page lock is used for normal faults. This
fixes races between hole instantiation and read faults of the same
index.
- Filesystem DAX PMD faults are disabled, and will be re-enabled when
PMD locking is implemented"
* tag 'dax-locking-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
dax: Remove i_mmap_lock protection
dax: Use radix tree entry lock to protect cow faults
dax: New fault locking
dax: Allow DAX code to replace exceptional entries
dax: Define DAX lock bit for radix tree exceptional entry
dax: Make huge page handling depend of CONFIG_BROKEN
dax: Fix condition for filling of PMD holes
76 lines
2.6 KiB
C
76 lines
2.6 KiB
C
#ifndef _LINUX_DAX_H
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#define _LINUX_DAX_H
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/radix-tree.h>
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#include <asm/pgtable.h>
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/* We use lowest available exceptional entry bit for locking */
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#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
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ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *,
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get_block_t, dio_iodone_t, int flags);
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int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);
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int dax_truncate_page(struct inode *, loff_t from, get_block_t);
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int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t);
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int __dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t);
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int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
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void dax_wake_mapping_entry_waiter(struct address_space *mapping,
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pgoff_t index, bool wake_all);
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#ifdef CONFIG_FS_DAX
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struct page *read_dax_sector(struct block_device *bdev, sector_t n);
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void dax_unlock_mapping_entry(struct address_space *mapping, pgoff_t index);
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int __dax_zero_page_range(struct block_device *bdev, sector_t sector,
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unsigned int offset, unsigned int length);
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#else
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static inline struct page *read_dax_sector(struct block_device *bdev,
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sector_t n)
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{
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return ERR_PTR(-ENXIO);
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}
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/* Shouldn't ever be called when dax is disabled. */
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static inline void dax_unlock_mapping_entry(struct address_space *mapping,
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pgoff_t index)
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{
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BUG();
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}
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static inline int __dax_zero_page_range(struct block_device *bdev,
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sector_t sector, unsigned int offset, unsigned int length)
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{
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return -ENXIO;
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}
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#endif
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#if defined(CONFIG_TRANSPARENT_HUGEPAGE)
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int dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *,
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unsigned int flags, get_block_t);
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int __dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *,
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unsigned int flags, get_block_t);
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#else
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static inline int dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
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pmd_t *pmd, unsigned int flags, get_block_t gb)
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{
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return VM_FAULT_FALLBACK;
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}
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#define __dax_pmd_fault dax_pmd_fault
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#endif
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int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
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#define dax_mkwrite(vma, vmf, gb) dax_fault(vma, vmf, gb)
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#define __dax_mkwrite(vma, vmf, gb) __dax_fault(vma, vmf, gb)
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static inline bool vma_is_dax(struct vm_area_struct *vma)
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{
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return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
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}
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static inline bool dax_mapping(struct address_space *mapping)
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{
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return mapping->host && IS_DAX(mapping->host);
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}
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struct writeback_control;
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int dax_writeback_mapping_range(struct address_space *mapping,
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struct block_device *bdev, struct writeback_control *wbc);
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#endif
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