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Commit 8e09f215 authored by Stefan Weinhuber's avatar Stefan Weinhuber Committed by Martin Schwidefsky
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[S390] dasd: add hyper PAV support to DASD device driver, part 1 



Parallel access volumes (PAV) is a storage server feature, that allows
to start multiple channel programs on the same DASD in parallel. It
defines alias devices which can be used as alternative paths to the
same disk. With the old base PAV support we only needed rudimentary
functionality in the DASD device driver. As the mapping between base
and alias devices was static, we just had to export an identifier
(uid) and could leave the combining of devices to external layers
like a device mapper multipath.
Now hyper PAV removes the requirement to dedicate alias devices to
specific base devices. Instead each alias devices can be combined with
multiple base device on a per request basis. This requires full
support by the DASD device driver as now each channel program itself
has to identify the target base device.
The changes to the dasd device driver and the ECKD discipline are:
- Separate subchannel device representation (dasd_device) from block
  device representation (dasd_block). Only base devices are block
  devices.
- Gather information about base and alias devices and possible
  combinations.
- For each request decide which dasd_device should be used (base or
  alias) and build specific channel program.
- Support summary unit checks, which allow the storage server to
  upgrade / downgrade between base and hyper PAV at runtime (support
  is mandatory).

Signed-off-by: default avatarStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 0ac30be4

drivers/s390/block/Makefile

+2 −2
Original line number Diff line number Diff line
@@ -2,8 +2,8 @@ 
# S/390 block devices

#



dasd_eckd_mod-objs := dasd_eckd.o dasd_3990_erp.o dasd_9343_erp.o

dasd_fba_mod-objs  := dasd_fba.o dasd_3370_erp.o dasd_9336_erp.o

dasd_eckd_mod-objs := dasd_eckd.o dasd_3990_erp.o dasd_alias.o

dasd_fba_mod-objs  := dasd_fba.o

dasd_diag_mod-objs := dasd_diag.o

dasd_mod-objs      := dasd.o dasd_ioctl.o dasd_proc.o dasd_devmap.o \

			dasd_genhd.o dasd_erp.o

drivers/s390/block/dasd.c

+944 −736

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drivers/s390/block/dasd_3370_erp.c

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Original line number Diff line number Diff line 
/*

 * File...........: linux/drivers/s390/block/dasd_3370_erp.c

 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>

 * Bugreports.to..: <Linux390@de.ibm.com>

 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 2000

 *

 */



#define PRINTK_HEADER "dasd_erp(3370)"



#include "dasd_int.h"





/*

 * DASD_3370_ERP_EXAMINE

 *

 * DESCRIPTION

 *   Checks only for fatal/no/recover error.

 *   A detailed examination of the sense data is done later outside

 *   the interrupt handler.

 *

 *   The logic is based on the 'IBM 3880 Storage Control Reference' manual

 *   'Chapter 7. 3370 Sense Data'.

 *

 * RETURN VALUES

 *   dasd_era_none	no error

 *   dasd_era_fatal	for all fatal (unrecoverable errors)

 *   dasd_era_recover	for all others.

 */

dasd_era_t

dasd_3370_erp_examine(struct dasd_ccw_req * cqr, struct irb * irb)

{

	char *sense = irb->ecw;



	/* check for successful execution first */

	if (irb->scsw.cstat == 0x00 &&

	    irb->scsw.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))

		return dasd_era_none;

	if (sense[0] & 0x80) {	/* CMD reject */

		return dasd_era_fatal;

	}

	if (sense[0] & 0x40) {	/* Drive offline */

		return dasd_era_recover;

	}

	if (sense[0] & 0x20) {	/* Bus out parity */

		return dasd_era_recover;

	}

	if (sense[0] & 0x10) {	/* equipment check */

		if (sense[1] & 0x80) {

			return dasd_era_fatal;

		}

		return dasd_era_recover;

	}

	if (sense[0] & 0x08) {	/* data check */

		if (sense[1] & 0x80) {

			return dasd_era_fatal;

		}

		return dasd_era_recover;

	}

	if (sense[0] & 0x04) {	/* overrun */

		if (sense[1] & 0x80) {

			return dasd_era_fatal;

		}

		return dasd_era_recover;

	}

	if (sense[1] & 0x40) {	/* invalid blocksize */

		return dasd_era_fatal;

	}

	if (sense[1] & 0x04) {	/* file protected */

		return dasd_era_recover;

	}

	if (sense[1] & 0x01) {	/* operation incomplete */

		return dasd_era_recover;

	}

	if (sense[2] & 0x80) {	/* check data erroor */

		return dasd_era_recover;

	}

	if (sense[2] & 0x10) {	/* Env. data present */

		return dasd_era_recover;

	}

	/* examine the 24 byte sense data */

	return dasd_era_recover;



}				/* END dasd_3370_erp_examine */

drivers/s390/block/dasd_3990_erp.c

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drivers/s390/block/dasd_9336_erp.c

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+0 −41
Original line number Diff line number Diff line 
/*

 * File...........: linux/drivers/s390/block/dasd_9336_erp.c

 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>

 * Bugreports.to..: <Linux390@de.ibm.com>

 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 2000

 *

 */



#define PRINTK_HEADER "dasd_erp(9336)"



#include "dasd_int.h"





/*

 * DASD_9336_ERP_EXAMINE

 *

 * DESCRIPTION

 *   Checks only for fatal/no/recover error.

 *   A detailed examination of the sense data is done later outside

 *   the interrupt handler.

 *

 *   The logic is based on the 'IBM 3880 Storage Control Reference' manual

 *   'Chapter 7. 9336 Sense Data'.

 *

 * RETURN VALUES

 *   dasd_era_none	no error

 *   dasd_era_fatal	for all fatal (unrecoverable errors)

 *   dasd_era_recover	for all others.

 */

dasd_era_t

dasd_9336_erp_examine(struct dasd_ccw_req * cqr, struct irb * irb)

{

	/* check for successful execution first */

	if (irb->scsw.cstat == 0x00 &&

	    irb->scsw.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))

		return dasd_era_none;



	/* examine the 24 byte sense data */

	return dasd_era_recover;



}				/* END dasd_9336_erp_examine */