iov_iter.c: convert copy_from_iter() to iterate_and_advance

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

1 files changed, 15 insertions, 91 deletions

diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 17b7144c3165..791429d07965 100644
--- 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);