1 files changed, 266 insertions, 0 deletions
diff --git a/include/linux/uio.h b/include/linux/uio.h
new file mode 100644
index 000000000..422b1c01e
--- /dev/null
+++ b/include/linux/uio.h
@@ -0,0 +1,266 @@
+/*
+ *	Berkeley style UIO structures	-	Alan Cox 1994.
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ */
+#ifndef __LINUX_UIO_H
+#define __LINUX_UIO_H
+
+#include <linux/kernel.h>
+#include <linux/thread_info.h>
+#include <uapi/linux/uio.h>
+
+struct page;
+struct pipe_inode_info;
+
+struct kvec {
+	void *iov_base; /* and that should *never* hold a userland pointer */
+	size_t iov_len;
+};
+
+enum {
+	ITER_IOVEC = 0,
+	ITER_KVEC = 2,
+	ITER_BVEC = 4,
+	ITER_PIPE = 8,
+};
+
+struct iov_iter {
+	int type;
+	size_t iov_offset;
+	size_t count;
+	union {
+		const struct iovec *iov;
+		const struct kvec *kvec;
+		const struct bio_vec *bvec;
+		struct pipe_inode_info *pipe;
+	};
+	union {
+		unsigned long nr_segs;
+		struct {
+			int idx;
+			int start_idx;
+		};
+	};
+};
+
+/*
+ * Total number of bytes covered by an iovec.
+ *
+ * NOTE that it is not safe to use this function until all the iovec's
+ * segment lengths have been validated.  Because the individual lengths can
+ * overflow a size_t when added together.
+ */
+static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
+{
+	unsigned long seg;
+	size_t ret = 0;
+
+	for (seg = 0; seg < nr_segs; seg++)
+		ret += iov[seg].iov_len;
+	return ret;
+}
+
+static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
+{
+	return (struct iovec) {
+		.iov_base = iter->iov->iov_base + iter->iov_offset,
+		.iov_len = min(iter->count,
+			       iter->iov->iov_len - iter->iov_offset),
+	};
+}
+
+#define iov_for_each(iov, iter, start)				\
+	if (!((start).type & (ITER_BVEC | ITER_PIPE)))		\
+	for (iter = (start);					\
+	     (iter).count &&					\
+	     ((iov = iov_iter_iovec(&(iter))), 1);		\
+	     iov_iter_advance(&(iter), (iov).iov_len))
+
+size_t iov_iter_copy_from_user_atomic(struct page *page,
+		struct iov_iter *i, unsigned long offset, size_t bytes);
+void iov_iter_advance(struct iov_iter *i, size_t bytes);
+void iov_iter_revert(struct iov_iter *i, size_t bytes);
+int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
+size_t iov_iter_single_seg_count(const struct iov_iter *i);
+size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
+			 struct iov_iter *i);
+size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
+			 struct iov_iter *i);
+
+size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
+size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
+bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
+size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
+bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);
+
+static __always_inline __must_check
+size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
+{
+	if (unlikely(!check_copy_size(addr, bytes, true)))
+		return 0;
+	else
+		return _copy_to_iter(addr, bytes, i);
+}
+
+static __always_inline __must_check
+size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
+{
+	if (unlikely(!check_copy_size(addr, bytes, false)))
+		return 0;
+	else
+		return _copy_from_iter(addr, bytes, i);
+}
+
+static __always_inline __must_check
+bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
+{
+	if (unlikely(!check_copy_size(addr, bytes, false)))
+		return false;
+	else
+		return _copy_from_iter_full(addr, bytes, i);
+}
+
+static __always_inline __must_check
+size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
+{
+	if (unlikely(!check_copy_size(addr, bytes, false)))
+		return 0;
+	else
+		return _copy_from_iter_nocache(addr, bytes, i);
+}
+
+static __always_inline __must_check
+bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
+{
+	if (unlikely(!check_copy_size(addr, bytes, false)))
+		return false;
+	else
+		return _copy_from_iter_full_nocache(addr, bytes, i);
+}
+
+#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
+/*
+ * Note, users like pmem that depend on the stricter semantics of
+ * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
+ * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
+ * destination is flushed from the cache on return.
+ */
+size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i);
+#else
+#define _copy_from_iter_flushcache _copy_from_iter_nocache
+#endif
+
+#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE
+size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i);
+#else
+#define _copy_to_iter_mcsafe _copy_to_iter
+#endif
+
+static __always_inline __must_check
+size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
+{
+	if (unlikely(!check_copy_size(addr, bytes, false)))
+		return 0;
+	else
+		return _copy_from_iter_flushcache(addr, bytes, i);
+}
+
+static __always_inline __must_check
+size_t copy_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i)
+{
+	if (unlikely(!check_copy_size(addr, bytes, true)))
+		return 0;
+	else
+		return _copy_to_iter_mcsafe(addr, bytes, i);
+}
+
+size_t iov_iter_zero(size_t bytes, struct iov_iter *);
+unsigned long iov_iter_alignment(const struct iov_iter *i);
+unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
+void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
+			unsigned long nr_segs, size_t count);
+void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec,
+			unsigned long nr_segs, size_t count);
+void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec,
+			unsigned long nr_segs, size_t count);
+void iov_iter_pipe(struct iov_iter *i, int direction, struct pipe_inode_info *pipe,
+			size_t count);
+ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
+			size_t maxsize, unsigned maxpages, size_t *start);
+ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
+			size_t maxsize, size_t *start);
+int iov_iter_npages(const struct iov_iter *i, int maxpages);
+
+const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
+
+static inline size_t iov_iter_count(const struct iov_iter *i)
+{
+	return i->count;
+}
+
+static inline bool iter_is_iovec(const struct iov_iter *i)
+{
+	return !(i->type & (ITER_BVEC | ITER_KVEC | ITER_PIPE));
+}
+
+/*
+ * Get one of READ or WRITE out of iter->type without any other flags OR'd in
+ * with it.
+ *
+ * The ?: is just for type safety.
+ */
+#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & (READ | WRITE))
+
+/*
+ * Cap the iov_iter by given limit; note that the second argument is
+ * *not* the new size - it's upper limit for such.  Passing it a value
+ * greater than the amount of data in iov_iter is fine - it'll just do
+ * nothing in that case.
+ */
+static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
+{
+	/*
+	 * count doesn't have to fit in size_t - comparison extends both
+	 * operands to u64 here and any value that would be truncated by
+	 * conversion in assignement is by definition greater than all
+	 * values of size_t, including old i->count.
+	 */
+	if (i->count > count)
+		i->count = count;
+}
+
+/*
+ * reexpand a previously truncated iterator; count must be no more than how much
+ * we had shrunk it.
+ */
+static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
+{
+	i->count = count;
+}
+size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
+size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
+bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
+
+int import_iovec(int type, const struct iovec __user * uvector,
+		 unsigned nr_segs, unsigned fast_segs,
+		 struct iovec **iov, struct iov_iter *i);
+
+#ifdef CONFIG_COMPAT
+struct compat_iovec;
+int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
+		 unsigned nr_segs, unsigned fast_segs,
+		 struct iovec **iov, struct iov_iter *i);
+#endif
+
+int import_single_range(int type, void __user *buf, size_t len,
+		 struct iovec *iov, struct iov_iter *i);
+
+int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,
+			    int (*f)(struct kvec *vec, void *context),
+			    void *context);
+
+#endif