Signed-off-by: added [Re: [PATCH]: Flexible timeout infrastructure]

[Luben Tuikov <luben_tuikov@adaptec.com>]

Signed-off-by: Luben Tuikov <luben_tuikov@adaptec.com>

===== drivers/scsi/scsi.c 1.143 vs edited =====
--- 1.143/drivers/scsi/scsi.c	2004-04-28 12:32:09 -04:00
+++ edited/drivers/scsi/scsi.c	2004-06-14 15:13:12 -04:00
@@ -549,7 +549,12 @@
 		host->resetting = 0;
 	}
 
-	scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
+	/* If the LLDD claims to be able to handle its own command timeout,
+	 * don't start the timer.  It will start it before sending the command
+	 * to the LU.
+	 */
+	if (!host->hostt->eh_cmd_timed_out)
+		scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
 
 	scsi_log_send(cmd);
 
@@ -699,8 +704,9 @@
 	 * that function could really be.  It might be on another processor,
 	 * etc, etc.
 	 */
-	if (!scsi_delete_timer(cmd))
-		return;
+	if (!cmd->device->host->hostt->eh_cmd_timed_out)
+		if (!scsi_delete_timer(cmd))
+			return;
 
 	/*
 	 * Set the serial numbers back to zero
===== drivers/scsi/scsi_error.c 1.76 vs edited =====
--- 1.76/drivers/scsi/scsi_error.c	2004-06-04 12:54:06 -04:00
+++ edited/drivers/scsi/scsi_error.c	2004-06-14 15:13:53 -04:00
@@ -155,8 +155,8 @@
 }
 
 /**
- * scsi_times_out - Timeout function for normal scsi commands.
- * @scmd:	Cmd that is timing out.
+ * scsi_times_out - Timeout function for normal SCSI commands.
+ * @scmd:	Command that is timing out.
  *
  * Notes:
  *     We do not need to lock this.  There is the potential for a race
@@ -166,7 +166,16 @@
  **/
 void scsi_times_out(struct scsi_cmnd *scmd)
 {
+	int ret = EH_NONE;
+	
 	scsi_log_completion(scmd, TIMEOUT_ERROR);
+
+	if (scmd->device->host->hostt->eh_cmd_timed_out)
+		ret = scmd->device->host->hostt->eh_cmd_timed_out(scmd);
+
+	if (ret == EH_HANDLED)
+		return;
+	
 	if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
 		panic("Error handler thread not present at %p %p %s %d",
 		      scmd, scmd->device->host, __FILE__, __LINE__);
===== drivers/scsi/scsi_syms.c 1.47 vs edited =====
--- 1.47/drivers/scsi/scsi_syms.c	2004-05-19 13:46:14 -04:00
+++ edited/drivers/scsi/scsi_syms.c	2004-06-14 11:09:29 -04:00
@@ -107,3 +107,4 @@
  */
 EXPORT_SYMBOL(scsi_add_timer);
 EXPORT_SYMBOL(scsi_delete_timer);
+EXPORT_SYMBOL(scsi_times_out);
===== include/scsi/scsi.h 1.21 vs edited =====
--- 1.21/include/scsi/scsi.h	2004-04-21 12:54:43 -04:00
+++ edited/include/scsi/scsi.h	2004-06-14 14:33:15 -04:00
@@ -327,6 +327,12 @@
 #define SCSI_MLQUEUE_EH_RETRY    0x1057
 
 /*
+ * LLDD timeout handler return values
+ */
+#define EH_NONE        (0)
+#define EH_HANDLED     (1)
+
+/*
  *  Use these to separate status msg and our bytes
  *
  *  These are set by:
===== include/scsi/scsi_eh.h 1.2 vs edited =====
--- 1.2/include/scsi/scsi_eh.h	2004-06-04 07:45:01 -04:00
+++ edited/include/scsi/scsi_eh.h	2004-06-14 11:12:13 -04:00
@@ -7,10 +7,11 @@
 
 extern void scsi_add_timer(struct scsi_cmnd *, int,
 			   void (*)(struct scsi_cmnd *));
-extern int scsi_delete_timer(struct scsi_cmnd *);
+extern int  scsi_delete_timer(struct scsi_cmnd *);
+extern void scsi_times_out(struct scsi_cmnd *);
 extern void scsi_report_bus_reset(struct Scsi_Host *, int);
 extern void scsi_report_device_reset(struct Scsi_Host *, int, int);
-extern int scsi_block_when_processing_errors(struct scsi_device *);
+extern int  scsi_block_when_processing_errors(struct scsi_device *);
 extern void scsi_sleep(int);
 
 /*
===== include/scsi/scsi_host.h 1.17 vs edited =====
--- 1.17/include/scsi/scsi_host.h	2004-06-04 12:51:31 -04:00
+++ edited/include/scsi/scsi_host.h	2004-06-14 15:12:23 -04:00
@@ -125,6 +125,40 @@
 	int (* eh_bus_reset_handler)(struct scsi_cmnd *);
 	int (* eh_host_reset_handler)(struct scsi_cmnd *);
 
+
+	/*
+	 * If defined, SCSI Core will leave _all_ command timeout
+	 * handling to the LLDD.  The LLDD should call
+	 * scsi_add_timer(<cmd>,<timeout>,scsi_times_out) when
+	 * appropriate, possibly before sending the command to the LU,
+	 * and scsi_delete_timer(<cmd>) before returning it to SCSI
+	 * Core. That is, a SCSI command is passed to the LLDD (via
+	 * queuecommand()) _without_ a timer running and is expected
+	 * to be returned to SCSI Core (via scsi_done()) just the
+	 * same, without one running.
+	 *
+	 * This method is called whenever a SCSI command times out, if
+	 * the driver had called
+	 * scsi_add_timer(<cmd>,<timeout>,scsi_times_out) of course.
+	 *
+	 * Returns: EH_HANDLED or EH_NONE.
+	 * EH_HANDLED -- means that the LLDD has taken all steps
+	 * to ensure proper command recovery handling and had
+	 * A) either called scsi_done() and set the response/result
+	 * properly in the SCSI command structure,
+	 * XOR
+	 * B) resent the command to the LU.
+	 * EH_NONE -- SCSI Core should try to recover the command as
+	 * usual (eh recovery thread, etc).
+	 *
+	 * If this method is not defined, current/old behaviour is assumed.
+	 *
+	 * NOTE: This runs in interrupt context, so it cannot sleep.
+	 * 
+	 * STATUS: OPTIONAL
+	 */
+	int (* eh_cmd_timed_out)(struct scsi_cmnd *);
+
 	/*
 	 * Old EH handlers, no longer used. Make them warn the user of old
 	 * drivers by using a wrong type