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-rw-r--r--net/core/iovec.c24
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);