csum_and_copy_to_pipe_iter(): leave handling of csum_state to caller

... since all the logics is already there for use by iovec/kvec/etc.
cases.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 9ce83db..97e04c5 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -582,39 +582,34 @@ static __wsum csum_and_memcpy(void *to, const void *from, size_t len,
 }
 
 static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes,
-                                        struct csum_state *csstate,
-                                        struct iov_iter *i)
+                                        struct iov_iter *i, __wsum *sump)
 {
        struct pipe_inode_info *pipe = i->pipe;
        unsigned int p_mask = pipe->ring_size - 1;
-       __wsum sum = csstate->csum;
-       size_t off = csstate->off;
+       __wsum sum = *sump;
+       size_t off = 0;
        unsigned int i_head;
-       size_t n, r;
+       size_t r;
 
        if (!sanity(i))
                return 0;
 
-       bytes = n = push_pipe(i, bytes, &i_head, &r);
-       if (unlikely(!n))
-               return 0;
-       do {
-               size_t chunk = min_t(size_t, n, PAGE_SIZE - r);
+       bytes = push_pipe(i, bytes, &i_head, &r);
+       while (bytes) {
+               size_t chunk = min_t(size_t, bytes, PAGE_SIZE - r);
                char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page);
-               sum = csum_and_memcpy(p + r, addr, chunk, sum, off);
+               sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off);
                kunmap_local(p);
                i->head = i_head;
                i->iov_offset = r + chunk;
-               n -= chunk;
+               bytes -= chunk;
                off += chunk;
-               addr += chunk;
                r = 0;
                i_head++;
-       } while (n);
-       i->count -= bytes;
-       csstate->csum = sum;
-       csstate->off = off;
-       return bytes;
+       }
+       *sump = sum;
+       i->count -= off;
+       return off;
 }
 
 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
@@ -1669,15 +1664,15 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate,
        struct csum_state *csstate = _csstate;
        __wsum sum, next;
 
-       if (unlikely(iov_iter_is_pipe(i)))
-               return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i);
-
-       sum = csum_shift(csstate->csum, csstate->off);
        if (unlikely(iov_iter_is_discard(i))) {
                WARN_ON(1);     /* for now */
                return 0;
        }
-       iterate_and_advance(i, bytes, base, len, off, ({
+
+       sum = csum_shift(csstate->csum, csstate->off);
+       if (unlikely(iov_iter_is_pipe(i)))
+               bytes = csum_and_copy_to_pipe_iter(addr, bytes, i, &sum);
+       else iterate_and_advance(i, bytes, base, len, off, ({
                next = csum_and_copy_to_user(addr + off, base, len);
                sum = csum_block_add(sum, next, off);
                next ? 0 : len;