iov_iter.c: convert iov_iter_zero() 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 3214b9b493ae98d02eb178e18063bccb594e1917..39ad7137f739ebac65fa43f1f393799c0743f3d1 100644 (file)
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -349,50 +349,6 @@ done:
        return wanted - bytes;
 }
 
-static size_t zero_iovec(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 = __clear_user(buf, copy);
-       copy -= left;
-       skip += copy;
-       bytes -= copy;
-
-       while (unlikely(!left && bytes)) {
-               iov++;
-               buf = iov->iov_base;
-               copy = min(bytes, iov->iov_len);
-               left = __clear_user(buf, copy);
-               copy -= left;
-               skip = 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;
-}
-
 /*
  * Fault in the first iovec of the given iov_iter, to a maximum length
  * of bytes. Returns 0 on success, or non-zero if the memory could not be
@@ -548,43 +504,6 @@ static size_t copy_page_from_iter_bvec(struct page *page, size_t offset,
        return wanted;
 }
 
-static size_t zero_bvec(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_t(size_t, bytes, bvec->bv_len - skip);
-
-       memzero_page(bvec->bv_page, skip + bvec->bv_offset, copy);
-       skip += copy;
-       bytes -= copy;
-       while (bytes) {
-               bvec++;
-               copy = min(bytes, (size_t)bvec->bv_len);
-               memzero_page(bvec->bv_page, bvec->bv_offset, copy);
-               skip = 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;
-}
-
 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
                         struct iov_iter *i)
 {
@@ -625,11 +544,18 @@ EXPORT_SYMBOL(copy_from_iter);
 
 size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
 {
-       if (i->type & ITER_BVEC) {
-               return zero_bvec(bytes, i);
-       } else {
-               return zero_iovec(bytes, i);
-       }
+       if (unlikely(bytes > i->count))
+               bytes = i->count;
+
+       if (unlikely(!bytes))
+               return 0;
+
+       iterate_and_advance(i, bytes, v,
+               __clear_user(v.iov_base, v.iov_len),
+               memzero_page(v.bv_page, v.bv_offset, v.bv_len)
+       )
+
+       return bytes;
 }
 EXPORT_SYMBOL(iov_iter_zero);