return NULL;
 }
 
+static inline bool bitmap_test_range_all_set(const unsigned long *addr,
+                                            unsigned long start,
+                                            unsigned long nbits)
+{
+       unsigned long found_zero;
+
+       found_zero = find_next_zero_bit(addr, start + nbits, start);
+       return (found_zero == start + nbits);
+}
+
+static inline bool bitmap_test_range_all_zero(const unsigned long *addr,
+                                             unsigned long start,
+                                             unsigned long nbits)
+{
+       unsigned long found_set;
+
+       found_set = find_next_bit(addr, start + nbits, start);
+       return (found_set == start + nbits);
+}
+
 #endif
 
                unlock_page(page);
 }
 
-static bool bitmap_test_range_all_set(unsigned long *addr, unsigned int start,
-                                     unsigned int nbits)
-{
-       unsigned int found_zero;
-
-       found_zero = find_next_zero_bit(addr, start + nbits, start);
-       if (found_zero == start + nbits)
-               return true;
-       return false;
-}
-
-static bool bitmap_test_range_all_zero(unsigned long *addr, unsigned int start,
-                                      unsigned int nbits)
-{
-       unsigned int found_set;
-
-       found_set = find_next_bit(addr, start + nbits, start);
-       if (found_set == start + nbits)
-               return true;
-       return false;
-}
-
 #define subpage_calc_start_bit(fs_info, page, name, start, len)                \
 ({                                                                     \
        unsigned int start_bit;                                         \
 
 
                /* Check if zones in the region are all empty */
                if (btrfs_dev_is_sequential(device, pos) &&
-                   find_next_zero_bit(zinfo->empty_zones, end, begin) != end) {
+                   !bitmap_test_range_all_set(zinfo->empty_zones, begin, nzones)) {
                        pos += zinfo->zone_size;
                        continue;
                }
        struct btrfs_zoned_device_info *zinfo = device->zone_info;
        const u8 shift = zinfo->zone_size_shift;
        unsigned long begin = start >> shift;
-       unsigned long end = (start + size) >> shift;
+       unsigned long nbits = size >> shift;
        u64 pos;
        int ret;
 
        ASSERT(IS_ALIGNED(start, zinfo->zone_size));
        ASSERT(IS_ALIGNED(size, zinfo->zone_size));
 
-       if (end > zinfo->nr_zones)
+       if (begin + nbits > zinfo->nr_zones)
                return -ERANGE;
 
        /* All the zones are conventional */
-       if (find_next_bit(zinfo->seq_zones, end, begin) == end)
+       if (bitmap_test_range_all_zero(zinfo->seq_zones, begin, nbits))
                return 0;
 
        /* All the zones are sequential and empty */
-       if (find_next_zero_bit(zinfo->seq_zones, end, begin) == end &&
-           find_next_zero_bit(zinfo->empty_zones, end, begin) == end)
+       if (bitmap_test_range_all_set(zinfo->seq_zones, begin, nbits) &&
+           bitmap_test_range_all_set(zinfo->empty_zones, begin, nbits))
                return 0;
 
        for (pos = start; pos < start + size; pos += zinfo->zone_size) {