c791ace1e7
Since the introduction of FAULT_FLAG_SIZE to the vm_fault flag, it has been somewhat painful with getting the flags set and removed at the correct locations. More than one kernel oops was introduced due to difficulties of getting the placement correctly. Remove the flag values and introduce an input parameter to huge_fault that indicates the size of the page entry. This makes the code easier to trace and should avoid the issues we see with the fault flags where removal of the flag was necessary in the fallback paths. Link: http://lkml.kernel.org/r/148615748258.43180.1690152053774975329.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Nilesh Choudhury <nilesh.choudhury@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
96 lines
2.9 KiB
C
96 lines
2.9 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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struct iomap_ops;
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/*
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* We use lowest available bit in exceptional entry for locking, one bit for
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* the entry size (PMD) and two more to tell us if the entry is a huge zero
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* page (HZP) or an empty entry that is just used for locking. In total four
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* special bits.
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*
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* If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
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* EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
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* block allocation.
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*/
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#define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
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#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
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#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
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#define RADIX_DAX_HZP (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 inline unsigned long dax_radix_sector(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 inline void *dax_radix_locked_entry(sector_t sector, 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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}
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ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
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const struct iomap_ops *ops);
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int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
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const struct iomap_ops *ops);
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int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
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int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index);
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int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
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pgoff_t index);
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void dax_wake_mapping_entry_waiter(struct address_space *mapping,
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pgoff_t index, void *entry, 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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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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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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#ifdef CONFIG_FS_DAX_PMD
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static inline unsigned int dax_radix_order(void *entry)
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{
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if ((unsigned long)entry & RADIX_DAX_PMD)
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return PMD_SHIFT - PAGE_SHIFT;
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return 0;
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}
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#else
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static inline unsigned int dax_radix_order(void *entry)
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{
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return 0;
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}
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#endif
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int dax_pfn_mkwrite(struct vm_fault *vmf);
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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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