iov_iter.c: convert copy_from_iter() to iterate_and_advance

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

diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 17b7144..791429d 100644 (file)
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -142,51 +142,6 @@ static size_t copy_to_iter_iovec(void *from, size_t bytes, struct iov_iter *i)
        return wanted - bytes;
 }
 
-static size_t copy_from_iter_iovec(void *to, size_t bytes, struct iov_iter *i)
-{
-       size_t skip, copy, left, wanted;
-       const struct iovec *iov;
-       char __user *buf;
-
-       if (unlikely(bytes > i->count))
-               bytes = i->count;
-
-       if (unlikely(!bytes))
-               return 0;
-
-       wanted = bytes;
-       iov = i->iov;
-       skip = i->iov_offset;
-       buf = iov->iov_base + skip;
-       copy = min(bytes, iov->iov_len - skip);
-
-       left = __copy_from_user(to, buf, copy);
-       copy -= left;
-       skip += copy;
-       to += copy;
-       bytes -= copy;
-       while (unlikely(!left && bytes)) {
-               iov++;
-               buf = iov->iov_base;
-               copy = min(bytes, iov->iov_len);
-               left = __copy_from_user(to, buf, copy);
-               copy -= left;
-               skip = copy;
-               to += copy;
-               bytes -= copy;
-       }
-
-       if (skip == iov->iov_len) {
-               iov++;
-               skip = 0;
-       }
-       i->count -= wanted - bytes;
-       i->nr_segs -= iov - i->iov;
-       i->iov = iov;
-       i->iov_offset = skip;
-       return wanted - bytes;
-}
-
 static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
                         struct iov_iter *i)
 {
@@ -444,48 +399,6 @@ static size_t copy_to_iter_bvec(void *from, size_t bytes, struct iov_iter *i)
        return wanted - bytes;
 }
 
-static size_t copy_from_iter_bvec(void *to, size_t bytes, struct iov_iter *i)
-{
-       size_t skip, copy, wanted;
-       const struct bio_vec *bvec;
-
-       if (unlikely(bytes > i->count))
-               bytes = i->count;
-
-       if (unlikely(!bytes))
-               return 0;
-
-       wanted = bytes;
-       bvec = i->bvec;
-       skip = i->iov_offset;
-
-       copy = min(bytes, bvec->bv_len - skip);
-
-       memcpy_from_page(to, bvec->bv_page, bvec->bv_offset + skip, copy);
-
-       to += copy;
-       skip += copy;
-       bytes -= copy;
-
-       while (bytes) {
-               bvec++;
-               copy = min(bytes, (size_t)bvec->bv_len);
-               memcpy_from_page(to, bvec->bv_page, bvec->bv_offset, copy);
-               skip = copy;
-               to += copy;
-               bytes -= copy;
-       }
-       if (skip == bvec->bv_len) {
-               bvec++;
-               skip = 0;
-       }
-       i->count -= wanted;
-       i->nr_segs -= bvec - i->bvec;
-       i->bvec = bvec;
-       i->iov_offset = skip;
-       return wanted;
-}
-
 size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
        if (i->type & ITER_BVEC)
@@ -497,10 +410,21 @@ EXPORT_SYMBOL(copy_to_iter);
 
 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
-       if (i->type & ITER_BVEC)
-               return copy_from_iter_bvec(addr, bytes, i);
-       else
-               return copy_from_iter_iovec(addr, bytes, i);
+       char *to = addr;
+       if (unlikely(bytes > i->count))
+               bytes = i->count;
+
+       if (unlikely(!bytes))
+               return 0;
+
+       iterate_and_advance(i, bytes, v,
+               __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
+                                v.iov_len),
+               memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
+                                v.bv_offset, v.bv_len)
+       )
+
+       return bytes;
 }
 EXPORT_SYMBOL(copy_from_iter);