[libata] EH: freeze port before aborting commands

Call the ->freeze() hook before aborting qc's, because some hardware
requires special handling prior to accessing the taskfile registers
(for diagnosis/analysis/reset).  Most notably, hardware may wish to
disable the DMA engine or interrupts in the ->freeze() hook.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 79711b6..9159abe 100644 (file)
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -999,7 +999,9 @@ static void __ata_port_freeze(struct ata_port *ap)
  *     ata_port_freeze - abort & freeze port
  *     @ap: ATA port to freeze
  *
- *     Abort and freeze @ap.
+ *     Abort and freeze @ap.  The freeze operation must be called
+ *     first, because some hardware requires special operations
+ *     before the taskfile registers are accessible.
  *
  *     LOCKING:
  *     spin_lock_irqsave(host lock)
@@ -1013,8 +1015,8 @@ int ata_port_freeze(struct ata_port *ap)
 
        WARN_ON(!ap->ops->error_handler);
 
-       nr_aborted = ata_port_abort(ap);
        __ata_port_freeze(ap);
+       nr_aborted = ata_port_abort(ap);
 
        return nr_aborted;
 }