new primitive: iov_iter_alignment()
returns the value aligned as badly as the worst remaining segment
in iov_iter is. Use instead of open-coded equivalents.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 22ec1ef..2f762cc 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -195,3 +195,28 @@
return min(i->count, iov->iov_len - i->iov_offset);
}
EXPORT_SYMBOL(iov_iter_single_seg_count);
+
+unsigned long iov_iter_alignment(const struct iov_iter *i)
+{
+ const struct iovec *iov = i->iov;
+ unsigned long res;
+ size_t size = i->count;
+ size_t n;
+
+ if (!size)
+ return 0;
+
+ res = (unsigned long)iov->iov_base + i->iov_offset;
+ n = iov->iov_len - i->iov_offset;
+ if (n >= size)
+ return res | size;
+ size -= n;
+ res |= n;
+ while (size > (++iov)->iov_len) {
+ res |= (unsigned long)iov->iov_base | iov->iov_len;
+ size -= iov->iov_len;
+ }
+ res |= (unsigned long)iov->iov_base | size;
+ return res;
+}
+EXPORT_SYMBOL(iov_iter_alignment);