1 files changed, 37 insertions, 1 deletions

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 7ebccb5c1637..54c248526b55 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -560,6 +560,38 @@ static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
         return bytes;
 }
 
+static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes,
+                                __wsum *csum, struct iov_iter *i)
+{
+        struct pipe_inode_info *pipe = i->pipe;
+        size_t n, r;
+        size_t off = 0;
+        __wsum sum = *csum, next;
+        int idx;
+
+        if (!sanity(i))
+                return 0;
+
+        bytes = n = push_pipe(i, bytes, &idx, &r);
+        if (unlikely(!n))
+                return 0;
+        for ( ; n; idx = next_idx(idx, pipe), r = 0) {
+                size_t chunk = min_t(size_t, n, PAGE_SIZE - r);
+                char *p = kmap_atomic(pipe->bufs[idx].page);
+                next = csum_partial_copy_nocheck(addr, p + r, chunk, 0);
+                sum = csum_block_add(sum, next, off);
+                kunmap_atomic(p);
+                i->idx = idx;
+                i->iov_offset = r + chunk;
+                n -= chunk;
+                off += chunk;
+                addr += chunk;
+        }
+        i->count -= bytes;
+        *csum = sum;
+        return bytes;
+}
+
 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
 {
         const char *from = addr;
@@ -1438,8 +1470,12 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
         const char *from = addr;
         __wsum sum, next;
         size_t off = 0;
+
+        if (unlikely(iov_iter_is_pipe(i)))
+                return csum_and_copy_to_pipe_iter(addr, bytes, csum, i);
+
         sum = *csum;
-        if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
+        if (unlikely(iov_iter_is_discard(i))) {
                 WARN_ON(1);     /* for now */
                 return 0;
         }