mm: buffered write iterator
Add an iterator data structure to operate over an iovec. Add usercopy operators needed by generic_file_buffered_write, and convert that function over. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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committed by
Linus Torvalds

parent
08291429cf
commit
2f718ffc16
@@ -401,6 +401,39 @@ struct page;
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struct address_space;
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struct writeback_control;
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struct iov_iter {
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const struct iovec *iov;
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unsigned long nr_segs;
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size_t iov_offset;
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size_t count;
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};
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size_t iov_iter_copy_from_user_atomic(struct page *page,
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struct iov_iter *i, unsigned long offset, size_t bytes);
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size_t iov_iter_copy_from_user(struct page *page,
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struct iov_iter *i, unsigned long offset, size_t bytes);
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void iov_iter_advance(struct iov_iter *i, size_t bytes);
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int iov_iter_fault_in_readable(struct iov_iter *i);
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size_t iov_iter_single_seg_count(struct iov_iter *i);
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static inline void iov_iter_init(struct iov_iter *i,
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const struct iovec *iov, unsigned long nr_segs,
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size_t count, size_t written)
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{
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i->iov = iov;
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i->nr_segs = nr_segs;
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i->iov_offset = 0;
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i->count = count + written;
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iov_iter_advance(i, written);
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}
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static inline size_t iov_iter_count(struct iov_iter *i)
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{
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return i->count;
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}
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struct address_space_operations {
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int (*writepage)(struct page *page, struct writeback_control *wbc);
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int (*readpage)(struct file *, struct page *);
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