1 files changed, 28 insertions, 32 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 33b39d3ce2d3..eeeeda0481a2 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -3986,44 +3986,40 @@ fsm_start:
 static void ata_pio_task(void *_data)
 {
         struct ata_port *ap = _data;
-        unsigned long timeout;
-        int has_next;
+        struct ata_queued_cmd *qc;
+        u8 status;
+        int poll_next;
 
 fsm_start:
-        timeout = 0;
-        has_next = 1;
+        WARN_ON(ap->hsm_task_state == HSM_ST_IDLE);
 
-        switch (ap->hsm_task_state) {
-        case HSM_ST_FIRST:
-                has_next = ata_pio_first_block(ap);
-                break;
-
-        case HSM_ST:
-                ata_pio_block(ap);
-                break;
-
-        case HSM_ST_LAST:
-                has_next = ata_pio_complete(ap);
-                break;
-
-        case HSM_ST_POLL:
-        case HSM_ST_LAST_POLL:
-                timeout = ata_pio_poll(ap);
-                break;
-
-        case HSM_ST_TMOUT:
-        case HSM_ST_ERR:
-                ata_pio_error(ap);
-                return;
+        qc = ata_qc_from_tag(ap, ap->active_tag);
+        WARN_ON(qc == NULL);
 
-        default:
-                BUG();
-                return;
+        /*
+         * This is purely heuristic.  This is a fast path.
+         * Sometimes when we enter, BSY will be cleared in
+         * a chk-status or two.  If not, the drive is probably seeking
+         * or something.  Snooze for a couple msecs, then
+         * chk-status again.  If still busy, queue delayed work.
+         */
+        status = ata_busy_wait(ap, ATA_BUSY, 5);
+        if (status & ATA_BUSY) {
+                msleep(2);
+                status = ata_busy_wait(ap, ATA_BUSY, 10);
+                if (status & ATA_BUSY) {
+                        ata_port_queue_task(ap, ata_pio_task, ap, ATA_SHORT_PAUSE);
+                        return;
+                }
         }
 
-        if (timeout)
-                ata_port_queue_task(ap, ata_pio_task, ap, timeout);
-        else if (has_next)
+        /* move the HSM */
+        poll_next = ata_hsm_move(ap, qc, status, 1);
+
+        /* another command or interrupt handler
+         * may be running at this point.
+         */
+        if (poll_next)
                 goto fsm_start;
 }