[RFC PATCH v2 07/19] scsi: scsi_error: Add helper to handle scsi device's error command list

[Wenchao Hao]

Add helper scsi_sdev_eh() to handle scsi device's error command list,
it would perform some steps which can be done with LUN's IO blocked,
including check sense, start unit and reset lun.

Signed-off-by: Wenchao Hao <haowenchao2@xxxxxxxxxx>
---
 drivers/scsi/scsi_error.c | 37 +++++++++++++++++++++++++++++++++++++
 include/scsi/scsi_eh.h    |  2 ++
 2 files changed, 39 insertions(+)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 055c04470f5c..f24f081fc637 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -2510,6 +2510,43 @@ int scsi_error_handler(void *data)
 	return 0;
 }
 
+/*
+ * Single LUN error handle
+ *
+ * @work_q: list of scsi commands need to recovery
+ * @done_q: list of scsi commands handled
+ *
+ * return: return 1 if all commands in work_q is recoveryed, else 0 is returned
+ */
+int scsi_sdev_eh(struct scsi_device *sdev,
+		 struct list_head *work_q,
+		 struct list_head *done_q)
+{
+	int ret = 0;
+	struct scsi_cmnd *scmd;
+
+	SCSI_LOG_ERROR_RECOVERY(2, sdev_printk(KERN_INFO, sdev,
+		"%s:luneh: checking sense\n", current->comm));
+	ret = scsi_eh_get_sense(work_q, done_q);
+	if (ret)
+		return ret;
+
+	SCSI_LOG_ERROR_RECOVERY(2, sdev_printk(KERN_INFO, sdev,
+		"%s:luneh: start unit\n", current->comm));
+	scmd = list_first_entry(work_q, struct scsi_cmnd, eh_entry);
+	ret = scsi_eh_sdev_stu(scmd, work_q, done_q);
+	if (ret)
+		return ret;
+
+	SCSI_LOG_ERROR_RECOVERY(2, sdev_printk(KERN_INFO, sdev,
+		"%s:luneh reset LUN\n", current->comm));
+	scmd = list_first_entry(work_q, struct scsi_cmnd, eh_entry);
+	ret = scsi_eh_sdev_reset(scmd, work_q, done_q);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(scsi_sdev_eh);
+
 /*
  * Function:    scsi_report_bus_reset()
  *
diff --git a/include/scsi/scsi_eh.h b/include/scsi/scsi_eh.h
index 1ae08e81339f..5ce791063baf 100644
--- a/include/scsi/scsi_eh.h
+++ b/include/scsi/scsi_eh.h
@@ -18,6 +18,8 @@ extern int scsi_block_when_processing_errors(struct scsi_device *);
 extern bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
 					 struct scsi_sense_hdr *sshdr);
 extern enum scsi_disposition scsi_check_sense(struct scsi_cmnd *);
+extern int scsi_sdev_eh(struct scsi_device *sdev, struct list_head *workq,
+			struct list_head *doneq);
 
 static inline bool scsi_sense_is_deferred(const struct scsi_sense_hdr *sshdr)
 {
-- 
2.35.3