From 2f718ffc16c43a435d12919c75dbfad518abd056 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Tue, 16 Oct 2007 01:24:59 -0700 Subject: 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fs.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 500ffc0e4ac..86ce27c7255 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -401,6 +401,39 @@ struct page; struct address_space; struct writeback_control; +struct iov_iter { + const struct iovec *iov; + unsigned long nr_segs; + size_t iov_offset; + size_t count; +}; + +size_t iov_iter_copy_from_user_atomic(struct page *page, + struct iov_iter *i, unsigned long offset, size_t bytes); +size_t iov_iter_copy_from_user(struct page *page, + struct iov_iter *i, unsigned long offset, size_t bytes); +void iov_iter_advance(struct iov_iter *i, size_t bytes); +int iov_iter_fault_in_readable(struct iov_iter *i); +size_t iov_iter_single_seg_count(struct iov_iter *i); + +static inline void iov_iter_init(struct iov_iter *i, + const struct iovec *iov, unsigned long nr_segs, + size_t count, size_t written) +{ + i->iov = iov; + i->nr_segs = nr_segs; + i->iov_offset = 0; + i->count = count + written; + + iov_iter_advance(i, written); +} + +static inline size_t iov_iter_count(struct iov_iter *i) +{ + return i->count; +} + + struct address_space_operations { int (*writepage)(struct page *page, struct writeback_control *wbc); int (*readpage)(struct file *, struct page *); -- cgit v1.2.3