[PATCH] libata-eh: implement new EH

Implement new EH.  The exported interface is ata_do_eh() which is to
be called from ->error_handler and performs the following steps to
recover the failed port.

ata_eh_autopsy() : analyze SError/TF, determine the cause of failure
		   and required recovery actions and record it in
		   ap->eh_context
ata_eh_report()	 : report the failure to user
ata_eh_recover() : perform recovery actions described in ap->eh_context
ata_eh_finish()	 : finish failed qcs

LLDDs can customize error handling by modifying eh_context before
calling ata_do_eh() or, if necessary, doing so inbetween each major
steps by calling each step explicitly.
Signed-off-by: Tejun Heo <htejun@gmail.com>

drivers/scsi/libata-core.c

@@ -5440,3 +5440,4 @@ EXPORT_SYMBOL_GPL(ata_eh_freeze_port);
 EXPORT_SYMBOL_GPL(ata_eh_thaw_port);
 EXPORT_SYMBOL_GPL(ata_eh_qc_complete);
 EXPORT_SYMBOL_GPL(ata_eh_qc_retry);
+EXPORT_SYMBOL_GPL(ata_do_eh);

include/linux/libata.h

@@ -247,6 +247,8 @@ enum {
 
 	/* how hard are we gonna try to probe/recover devices */
 	ATA_PROBE_MAX_TRIES	= 3,
+	ATA_EH_RESET_TRIES	= 3,
+	ATA_EH_DEV_TRIES	= 3,
 };
 
 enum hsm_task_states {
@@ -727,6 +729,9 @@ extern void ata_eh_thaw_port(struct ata_port *ap);
 extern void ata_eh_qc_complete(struct ata_queued_cmd *qc);
 extern void ata_eh_qc_retry(struct ata_queued_cmd *qc);
 
+extern void ata_do_eh(struct ata_port *ap, ata_reset_fn_t softreset,
+		      ata_reset_fn_t hardreset, ata_postreset_fn_t postreset);
+
 /*
  * printk helpers
  */