+static int ata_eh_nr_in_flight(struct ata_port *ap)
+{
+ unsigned int tag;
+ int nr = 0;
+
+ /* count only non-internal commands */
+ for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++)
+ if (ata_qc_from_tag(ap, tag))
+ nr++;
+
+ return nr;
+}
+
+void ata_eh_fastdrain_timerfn(unsigned long arg)
+{
+ struct ata_port *ap = (void *)arg;
+ unsigned long flags;
+ int cnt;
+
+ spin_lock_irqsave(ap->lock, flags);
+
+ cnt = ata_eh_nr_in_flight(ap);
+
+ /* are we done? */
+ if (!cnt)
+ goto out_unlock;
+
+ if (cnt == ap->fastdrain_cnt) {
+ unsigned int tag;
+
+ /* No progress during the last interval, tag all
+ * in-flight qcs as timed out and freeze the port.
+ */
+ for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++) {
+ struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
+ if (qc)
+ qc->err_mask |= AC_ERR_TIMEOUT;
+ }
+
+ ata_port_freeze(ap);
+ } else {
+ /* some qcs have finished, give it another chance */
+ ap->fastdrain_cnt = cnt;
+ ap->fastdrain_timer.expires =
+ jiffies + ATA_EH_FASTDRAIN_INTERVAL;
+ add_timer(&ap->fastdrain_timer);
+ }
+
+ out_unlock:
+ spin_unlock_irqrestore(ap->lock, flags);
+}
+
+/**
+ * ata_eh_set_pending - set ATA_PFLAG_EH_PENDING and activate fast drain
+ * @ap: target ATA port
+ * @fastdrain: activate fast drain
+ *
+ * Set ATA_PFLAG_EH_PENDING and activate fast drain if @fastdrain
+ * is non-zero and EH wasn't pending before. Fast drain ensures
+ * that EH kicks in in timely manner.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host lock)
+ */
+static void ata_eh_set_pending(struct ata_port *ap, int fastdrain)
+{
+ int cnt;
+
+ /* already scheduled? */
+ if (ap->pflags & ATA_PFLAG_EH_PENDING)
+ return;
+
+ ap->pflags |= ATA_PFLAG_EH_PENDING;
+
+ if (!fastdrain)
+ return;
+
+ /* do we have in-flight qcs? */
+ cnt = ata_eh_nr_in_flight(ap);
+ if (!cnt)
+ return;
+
+ /* activate fast drain */
+ ap->fastdrain_cnt = cnt;
+ ap->fastdrain_timer.expires = jiffies + ATA_EH_FASTDRAIN_INTERVAL;
+ add_timer(&ap->fastdrain_timer);
+}
+