iov_iter.c: convert iov_iter_zero() to iterate_and_advance

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

1 files changed, 12 insertions, 86 deletions

diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 3214b9b493ae..39ad7137f739 100644
--- 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);