net: move iov_pages() to net/core/iovec.c

To let it be reused and reduce code duplication.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 0 deletions

diff --git a/net/core/iovec.c b/net/core/iovec.c
index de178e462682..b77eeecc0011 100644
--- a/net/core/iovec.c
+++ b/net/core/iovec.c
@@ -212,3 +212,27 @@ out_fault:
         goto out;
 }
 EXPORT_SYMBOL(csum_partial_copy_fromiovecend);
+
+unsigned long iov_pages(const struct iovec *iov, int offset,
+                        unsigned long nr_segs)
+{
+        unsigned long seg, base;
+        int pages = 0, len, size;
+
+        while (nr_segs && (offset >= iov->iov_len)) {
+                offset -= iov->iov_len;
+                ++iov;
+                --nr_segs;
+        }
+
+        for (seg = 0; seg < nr_segs; seg++) {
+                base = (unsigned long)iov[seg].iov_base + offset;
+                len = iov[seg].iov_len - offset;
+                size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
+                pages += size;
+                offset = 0;
+        }
+
+        return pages;
+}
+EXPORT_SYMBOL(iov_pages);