+/**
+ * ata_dev_next - device iteration helper
+ * @dev: the previous device, NULL to start
+ * @link: ATA link containing devices to iterate
+ * @mode: iteration mode, one of ATA_DITER_*
+ *
+ * LOCKING:
+ * Host lock or EH context.
+ *
+ * RETURNS:
+ * Pointer to the next device.
+ */
+struct ata_device *ata_dev_next(struct ata_device *dev, struct ata_link *link,
+ enum ata_dev_iter_mode mode)
+{
+ BUG_ON(mode != ATA_DITER_ENABLED && mode != ATA_DITER_ENABLED_REVERSE &&
+ mode != ATA_DITER_ALL && mode != ATA_DITER_ALL_REVERSE);
+
+ /* NULL dev indicates start of iteration */
+ if (!dev)
+ switch (mode) {
+ case ATA_DITER_ENABLED:
+ case ATA_DITER_ALL:
+ dev = link->device;
+ goto check;
+ case ATA_DITER_ENABLED_REVERSE:
+ case ATA_DITER_ALL_REVERSE:
+ dev = link->device + ata_link_max_devices(link) - 1;
+ goto check;
+ }
+
+ next:
+ /* move to the next one */
+ switch (mode) {
+ case ATA_DITER_ENABLED:
+ case ATA_DITER_ALL:
+ if (++dev < link->device + ata_link_max_devices(link))
+ goto check;
+ return NULL;
+ case ATA_DITER_ENABLED_REVERSE:
+ case ATA_DITER_ALL_REVERSE:
+ if (--dev >= link->device)
+ goto check;
+ return NULL;
+ }
+
+ check:
+ if ((mode == ATA_DITER_ENABLED || mode == ATA_DITER_ENABLED_REVERSE) &&
+ !ata_dev_enabled(dev))
+ goto next;
+ return dev;
+}
+