Add HP hardware handler support to dm-multipath

205 lines not on this page · raw message

Index: linux-2.6.23-rc1/drivers/md/dm-hw-handler.h
===================================================================
@@ -58,5 +58,6 @@ unsigned dm_scsi_err_handler(struct hw_h
 #define MP_FAIL_PATH 1
 #define MP_BYPASS_PG 2
 #define MP_ERROR_IO  4	/* Don't retry this I/O */
+#define MP_RETRY 8
 
 #endif

111 lines not on this page · raw message

Index: linux-2.6.23-rc1/drivers/md/dm-mpath-hp-sw.c
===================================================================
@@ -18,18 +18,52 @@
 #include <linux/types.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_dbg.h>
 
 #include "dm.h"
 #include "dm-hw-handler.h"
 
 #define DM_MSG_PREFIX "multipath hp_sw"
 #define HP_DM_HWH_NAME "hp_sw"
-#define HP_DM_HWH_VER "0.0.3"
+#define HP_DM_HWH_VER "1.0.0"
 
 struct hp_sw_context {
 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 };
 
+/**
+ * hp_sw_error_is_retryable - Is an HP-specific check condition retryable?
+ * @req: path activation request
+ *
+ * Examine error codes of request and determine whether the error is retryable.
+ * Some error codes are already retried by scsi-ml (see
+ * scsi_decide_disposition), but some HP specific codes are not.
+ * The intent of this routine is to supply the logic for the HP specific
+ * check conditions.
+ *
+ * Returns:
+ *  1 - command completed with retryable error
+ *  0 - command completed with non-retryable error
+ *
+ * Possible optimizations
+ * 1. More hardware-specific error codes
+ */
+static int hp_sw_error_is_retryable(struct request *req)
+{
+	/*
+	 * NOT_READY is known to be retryable
+	 * For now we just dump out the sense data and call it retryable
+	 */
+	if (status_byte(req->errors) == CHECK_CONDITION)
+		__scsi_print_sense("hp_sw", req->sense, req->sense_len);
+
+	/*
+	 * At this point we don't have complete information about all the error
+	 * codes from this hardware, so we are just conservative and retry
+	 * when in doubt.
+	 */
+	return 1;
+}
 
 /**
  * hp_sw_end_io - Completion handler for HP path activation.

@@ -41,8 +75,6 @@ struct hp_sw_context {
  *
  * Context: scsi-ml softirq
  *
- * Possible optimizations
- * 1. Actually check sense data for retryable error (e.g. NOT_READY)
  */
 static void hp_sw_end_io(struct request *req, int error)
 {

@@ -54,11 +86,17 @@ static void hp_sw_end_io(struct request 
 		DMDEBUG("%s path activation command - success",
 			path->dev->name);
 	} else {
-		DMWARN("%s path activation command - error=0x%x",
+		if (hp_sw_error_is_retryable(req)) {
+			DMDEBUG("%s path activation command - retry",
+				path->dev->name);
+			err_flags = MP_RETRY;
+			goto out;
+		}
+		DMWARN("%s path activation fail - error=0x%x",
 		       path->dev->name, error);
 		err_flags = MP_FAIL_PATH;
 	}
-
+out:
 	req->end_io_data = NULL;
 	__blk_put_request(req->q, req);
 	dm_pg_init_complete(path, err_flags);

@@ -136,7 +174,7 @@ static void hp_sw_pg_init(struct hw_hand
 	if (!req) {
 		DMERR("%s path activation command - allocation fail",
 		      path->dev->name);
-		goto fail;
+		goto retry;
 	}
 
 	DMDEBUG("%s path activation command - sent", path->dev->name);

@@ -144,8 +182,8 @@ static void hp_sw_pg_init(struct hw_hand
 	blk_execute_rq_nowait(req->q, NULL, req, 1, hp_sw_end_io);
 	return;
 
-fail:
-	dm_pg_init_complete(path, MP_FAIL_PATH);
+retry:
+	dm_pg_init_complete(path, MP_RETRY);
 }
 
 static int hp_sw_create(struct hw_handler *hwh, unsigned argc, char **argv)