iov_iter.c: convert copy_to_iter() to iterate_and_advance

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

1 files changed, 9 insertions, 82 deletions

diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 791429d07965..666654498ccf 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -97,51 +97,6 @@
         i->iov_offset = skip;                                   \
 }
 
-static size_t copy_to_iter_iovec(void *from, 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_to_user(buf, from, copy);
-        copy -= left;
-        skip += copy;
-        from += copy;
-        bytes -= copy;
-        while (unlikely(!left && bytes)) {
-                iov++;
-                buf = iov->iov_base;
-                copy = min(bytes, iov->iov_len);
-                left = __copy_to_user(buf, from, copy);
-                copy -= left;
-                skip = copy;
-                from += 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)
 {
@@ -360,51 +315,23 @@ static void memzero_page(struct page *page, size_t offset, size_t len)
         kunmap_atomic(addr);
 }
 
-static size_t copy_to_iter_bvec(void *from, size_t bytes, struct iov_iter *i)
+size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
-        size_t skip, copy, wanted;
-        const struct bio_vec *bvec;
-
+        char *from = addr;
         if (unlikely(bytes > i->count))
                 bytes = i->count;
 
         if (unlikely(!bytes))
                 return 0;
 
-        wanted = bytes;
-        bvec = i->bvec;
-        skip = i->iov_offset;
-        copy = min_t(size_t, bytes, bvec->bv_len - skip);
-
-        memcpy_to_page(bvec->bv_page, skip + bvec->bv_offset, from, copy);
-        skip += copy;
-        from += copy;
-        bytes -= copy;
-        while (bytes) {
-                bvec++;
-                copy = min(bytes, (size_t)bvec->bv_len);
-                memcpy_to_page(bvec->bv_page, bvec->bv_offset, from, copy);
-                skip = copy;
-                from += copy;
-                bytes -= copy;
-        }
-        if (skip == bvec->bv_len) {
-                bvec++;
-                skip = 0;
-        }
-        i->count -= wanted - bytes;
-        i->nr_segs -= bvec - i->bvec;
-        i->bvec = bvec;
-        i->iov_offset = skip;
-        return wanted - bytes;
-}
+        iterate_and_advance(i, bytes, v,
+                __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
+                               v.iov_len),
+                memcpy_to_page(v.bv_page, v.bv_offset,
+                               (from += v.bv_len) - v.bv_len, v.bv_len)
+        )
 
-size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)
-{
-        if (i->type & ITER_BVEC)
-                return copy_to_iter_bvec(addr, bytes, i);
-        else
-                return copy_to_iter_iovec(addr, bytes, i);
+        return bytes;
 }
 EXPORT_SYMBOL(copy_to_iter);