clean up copy_mc_pipe_to_iter()

... and we don't need kmap_atomic() there - kmap_local_page() is fine.

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

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index a827991..9ce83db 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -642,19 +642,6 @@ static int copyout_mc(void __user *to, const void *from, size_t n)
        return n;
 }
 
-static unsigned long copy_mc_to_page(struct page *page, size_t offset,
-               const char *from, size_t len)
-{
-       unsigned long ret;
-       char *to;
-
-       to = kmap_atomic(page);
-       ret = copy_mc_to_kernel(to + offset, from, len);
-       kunmap_atomic(to);
-
-       return ret;
-}
-
 static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes,
                                struct iov_iter *i)
 {
@@ -666,25 +653,23 @@ static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes,
        if (!sanity(i))
                return 0;
 
-       bytes = n = push_pipe(i, bytes, &i_head, &off);
-       if (unlikely(!n))
-               return 0;
-       do {
+       n = push_pipe(i, bytes, &i_head, &off);
+       while (n) {
                size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
+               char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page);
                unsigned long rem;
-
-               rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page,
-                                           off, addr, chunk);
+               rem = copy_mc_to_kernel(p + off, addr + xfer, chunk);
+               chunk -= rem;
+               kunmap_local(p);
                i->head = i_head;
-               i->iov_offset = off + chunk - rem;
-               xfer += chunk - rem;
+               i->iov_offset = off + chunk;
+               xfer += chunk;
                if (rem)
                        break;
                n -= chunk;
-               addr += chunk;
                off = 0;
                i_head++;
-       } while (n);
+       }
        i->count -= xfer;
        return xfer;
 }