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* [PATCH] Midlayer initiated START_UNIT
@ 2004-01-29 22:15 Brian King
  2004-02-17  7:36 ` Sachin Mhatre (smhatre)
  0 siblings, 1 reply; 5+ messages in thread
From: Brian King @ 2004-01-29 22:15 UTC (permalink / raw)
  To: James.Bottomley; +Cc: linux-scsi

James,

This is a patch to issue a START_UNIT command from the midlayer error handler.
The ipr driver, which is currently out for review needs this to function properly.
Any time the adapter gets reset, the disk array resources under the ipr adapter
require another START_UNIT command. This causes problems with the current error
handling and these devices get taken offline when this occurs.

This was being handled by the ipr driver itself, but Christoph did not like
seeing a LLDD issuing commands to devices, hence the patch.

http://marc.theaimsgroup.com/?l=linux-scsi&m=107462193622673&w=2

Patch is against 2.6.2-rc2.

Thanks



-- 
Brian King
eServer Storage I/O
IBM Linux Technology Center


^ permalink raw reply	[flat|nested] 5+ messages in thread
* [PATCH] Midlayer initiated START_UNIT
@ 2004-01-26 19:43 Brian King
  0 siblings, 0 replies; 5+ messages in thread
From: Brian King @ 2004-01-26 19:43 UTC (permalink / raw)
  To: linux-scsi

[-- Attachment #1: Type: text/plain, Size: 543 bytes --]

The ipr driver that is currently out for review talks to disk array devices
that require a START_UNIT prior to media ops, similar to normal scsi devices.
However, any time the adapter gets reset, these devices end up needing another
START_UNIT. This causes problems with the current error handling and these
devices get taken offline when this occurs. Attached is a patch which will
better handle these devices and issue a START_UNIT from the error handler
when appropriate.





-- 
Brian King
eServer Storage I/O
IBM Linux Technology Center

[-- Attachment #2: patch-2.6.1-start_unit --]
[-- Type: text/plain, Size: 5216 bytes --]

diff -Naur linux-2.6.1/drivers/scsi/scsi_error.c linux-2.6.1-start_unit/drivers/scsi/scsi_error.c
--- linux-2.6.1/drivers/scsi/scsi_error.c	Fri Jan  9 00:59:03 2004
+++ linux-2.6.1-start_unit/drivers/scsi/scsi_error.c	Mon Jan 26 10:51:37 2004
@@ -37,6 +37,8 @@
 #define SENSE_TIMEOUT (10*HZ)
 #endif
 
+#define START_UNIT_TIMEOUT (30*HZ)
+
 /*
  * These should *probably* be handled by the host itself.
  * Since it is allowed to sleep, it probably should.
@@ -282,6 +284,15 @@
 			(scmd->sense_buffer[13] == 0x01)) {
 			return NEEDS_RETRY;
 		}
+		/*
+		 * if the device is not started, we need to wake
+		 * the error handler to start the motor
+		 */
+		if (scmd->device->allow_restart &&
+		    (scmd->sense_buffer[12] == 0x04) &&
+		    (scmd->sense_buffer[13] == 0x02)) {
+			return FAILED;
+		}
 		return SUCCESS;
 
 		/* these three are not supported */
@@ -829,6 +840,105 @@
 }
 
 /**
+ * scsi_eh_try_stu - Send START_UNIT to device.
+ * @scmd:	Scsi cmd to send START_UNIT
+ *
+ * Return value:
+ *    0 - Device is ready. 1 - Device NOT ready.
+ **/
+static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
+{
+	static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
+	int rtn;
+
+	if (!scmd->device->allow_restart)
+		return 1;
+
+	memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
+
+	/*
+	 * zero the sense buffer.  the scsi spec mandates that any
+	 * untransferred sense data should be interpreted as being zero.
+	 */
+	memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
+
+	scmd->request_buffer = NULL;
+	scmd->request_bufflen = 0;
+	scmd->use_sg = 0;
+	scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
+	scmd->underflow = 0;
+	scmd->sc_data_direction = DMA_NONE;
+
+	rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
+
+	/*
+	 * when we eventually call scsi_finish, we really wish to complete
+	 * the original request, so let's restore the original data. (db)
+	 */
+	scsi_setup_cmd_retry(scmd);
+
+	/*
+	 * hey, we are done.  let's look to see what happened.
+	 */
+	SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
+		__FUNCTION__, scmd, rtn));
+	if (rtn == SUCCESS)
+		return 0;
+	return 1;
+}
+
+ /**
+ * scsi_eh_stu - send START_UNIT if needed
+ * @shost:	scsi host being recovered.
+ * @eh_done_q:	list_head for processed commands.
+ *
+ * Notes:
+ *    If commands are failing due to not ready, initializing command required,
+ *	try revalidating the device, which will end up sending a start unit. 
+ **/
+static int scsi_eh_stu(struct Scsi_Host *shost,
+			      struct list_head *work_q,
+			      struct list_head *done_q)
+{
+	struct list_head *lh, *lh_sf;
+	struct scsi_cmnd *scmd, *stu_scmd;
+	struct scsi_device *sdev;
+
+	shost_for_each_device(sdev, shost) {
+		stu_scmd = NULL;
+		list_for_each_entry(scmd, work_q, eh_entry)
+			if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
+			    scsi_check_sense(scmd) == FAILED ) {
+				stu_scmd = scmd;
+				break;
+			}
+
+		if (!stu_scmd)
+			continue;
+
+		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
+						  " 0x%p\n", current->comm, sdev));
+
+		if (!scsi_eh_try_stu(stu_scmd)) {
+			if (!sdev->online || !scsi_eh_tur(stu_scmd)) {
+				list_for_each_safe(lh, lh_sf, work_q) {
+					scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
+					if (scmd->device == sdev)
+						scsi_eh_finish_cmd(scmd, done_q);
+				}
+			}
+		} else {
+			SCSI_LOG_ERROR_RECOVERY(3,
+						printk("%s: START_UNIT failed to sdev:"
+						       " 0x%p\n", current->comm, sdev));
+		}
+	}
+
+	return list_empty(work_q);
+}
+
+
+/**
  * scsi_eh_bus_device_reset - send bdr if needed
  * @shost:	scsi host being recovered.
  * @eh_done_q:	list_head for processed commands.
@@ -1033,7 +1143,9 @@
 		if (rtn == SUCCESS) {
 			list_for_each_safe(lh, lh_sf, work_q) {
 				scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
-				if (!scmd->device->online || !scsi_eh_tur(scmd)) 
+				if (!scmd->device->online ||
+				    (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
+				    !scsi_eh_tur(scmd))
 					scsi_eh_finish_cmd(scmd, done_q);
 			}
 		} else {
@@ -1401,10 +1513,11 @@
 			       struct list_head *work_q,
 			       struct list_head *done_q)
 {
-	if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
-		if (!scsi_eh_bus_reset(shost, work_q, done_q))
-			if (!scsi_eh_host_reset(work_q, done_q))
-				scsi_eh_offline_sdevs(work_q, done_q);
+	if (!scsi_eh_stu(shost, work_q, done_q))
+		if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
+			if (!scsi_eh_bus_reset(shost, work_q, done_q))
+				if (!scsi_eh_host_reset(work_q, done_q))
+					scsi_eh_offline_sdevs(work_q, done_q);
 }
 
 /**
diff -Naur linux-2.6.1/include/scsi/scsi_device.h linux-2.6.1-start_unit/include/scsi/scsi_device.h
--- linux-2.6.1/include/scsi/scsi_device.h	Fri Jan  9 00:59:06 2004
+++ linux-2.6.1-start_unit/include/scsi/scsi_device.h	Mon Jan 26 08:48:07 2004
@@ -94,6 +94,7 @@
 	unsigned skip_ms_page_8:1;	/* do not use MODE SENSE page 0x08 */
 	unsigned skip_ms_page_3f:1;	/* do not use MODE SENSE page 0x3f */
 	unsigned no_start_on_add:1;	/* do not issue start on add */
+	unsigned allow_restart:1; /* issue START_UNIT in error handler */
 
 	unsigned int device_blocked;	/* Device returned QUEUE_FULL. */
 

^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2004-02-17 14:27 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2004-01-29 22:15 [PATCH] Midlayer initiated START_UNIT Brian King
2004-02-17  7:36 ` Sachin Mhatre (smhatre)
2004-02-17  8:04   ` Matthew Dharm
2004-02-17 14:27     ` Brian King
  -- strict thread matches above, loose matches on Subject: below --
2004-01-26 19:43 Brian King

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