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linux-davinci-2.6.23
Commit 4111796d authored by Stefan Bader's avatar Stefan Bader Committed by Linus Torvalds
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[PATCH] s390: channel tape fixes 

Tape driver fixes:
 - Added deferred condition handling to tape driver core.
 - Added ability to handle busy conditions.
 - Code cleanup.
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 6bb0e010
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Showing with 181 additions and 125 deletions
drivers/s390/char/tape.h
View file @ 4111796d
......@@ -3,10 +3,11 @@
* tape device driver for 3480/3490E/3590 tapes.
*
* S390 and zSeries version
* Copyright (C) 2001,2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Copyright (C) 2001,2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Tuan Ngo-Anh <ngoanh@de.ibm.com>
* Martin Schwidefsky <schwidefsky@de.ibm.com>
* Stefan Bader <shbader@de.ibm.com>
*/
#ifndef _TAPE_H
......@@ -111,6 +112,7 @@ enum tape_request_status {
TAPE_REQUEST_QUEUED, /* request is queued to be processed */
TAPE_REQUEST_IN_IO, /* request is currently in IO */
TAPE_REQUEST_DONE, /* request is completed. */
TAPE_REQUEST_CANCEL, /* request should be canceled. */
};
/* Tape CCW request */
......@@ -237,6 +239,9 @@ struct tape_device {
/* Block dev frontend data */
struct tape_blk_data blk_data;
#endif
/* Function to start or stop the next request later. */
struct work_struct tape_dnr;
};
/* Externals from tape_core.c */
......
drivers/s390/char/tape_core.c
View file @ 4111796d
......@@ -3,11 +3,12 @@
* basic function of the tape device driver
*
* S390 and zSeries version
* Copyright (C) 2001,2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Copyright (C) 2001,2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Michael Holzheu <holzheu@de.ibm.com>
* Tuan Ngo-Anh <ngoanh@de.ibm.com>
* Martin Schwidefsky <schwidefsky@de.ibm.com>
* Stefan Bader <shbader@de.ibm.com>
*/
#include <linux/config.h>
......@@ -28,7 +29,7 @@
#define PRINTK_HEADER "TAPE_CORE: "
static void __tape_do_irq (struct ccw_device *, unsigned long, struct irb *);
static void __tape_remove_request(struct tape_device *, struct tape_request *);
static void tape_delayed_next_request(void * data);
/*
* One list to contain all tape devices of all disciplines, so
......@@ -257,7 +258,7 @@ tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
* Stop running ccw. Has to be called with the device lock held.
*/
static inline int
__tape_halt_io(struct tape_device *device, struct tape_request *request)
__tape_cancel_io(struct tape_device *device, struct tape_request *request)
{
int retries;
int rc;
......@@ -270,20 +271,23 @@ __tape_halt_io(struct tape_device *device, struct tape_request *request)
for (retries = 0; retries < 5; retries++) {
rc = ccw_device_clear(device->cdev, (long) request);
if (rc == 0) { /* Termination successful */
request->rc = -EIO;
request->status = TAPE_REQUEST_DONE;
return 0;
switch (rc) {
case 0:
request->status = TAPE_REQUEST_DONE;
return 0;
case -EBUSY:
request->status = TAPE_REQUEST_CANCEL;
schedule_work(&device->tape_dnr);
return 0;
case -ENODEV:
DBF_EXCEPTION(2, "device gone, retry\n");
break;
case -EIO:
DBF_EXCEPTION(2, "I/O error, retry\n");
break;
default:
BUG();
}
if (rc == -ENODEV)
DBF_EXCEPTION(2, "device gone, retry\n");
else if (rc == -EIO)
DBF_EXCEPTION(2, "I/O error, retry\n");
else if (rc == -EBUSY)
DBF_EXCEPTION(2, "device busy, retry late\n");
else
BUG();
}
return rc;
......@@ -473,6 +477,7 @@ tape_alloc_device(void)
*device->modeset_byte = 0;
device->first_minor = -1;
atomic_set(&device->ref_count, 1);
INIT_WORK(&device->tape_dnr, tape_delayed_next_request, device);
return device;
}
......@@ -708,54 +713,119 @@ tape_free_request (struct tape_request * request)
kfree(request);
}
static inline int
__tape_start_io(struct tape_device *device, struct tape_request *request)
{
int rc;
#ifdef CONFIG_S390_TAPE_BLOCK
if (request->op == TO_BLOCK)
device->discipline->check_locate(device, request);
#endif
rc = ccw_device_start(
device->cdev,
request->cpaddr,
(unsigned long) request,
0x00,
request->options
);
if (rc == 0) {
request->status = TAPE_REQUEST_IN_IO;
} else if (rc == -EBUSY) {
/* The common I/O subsystem is currently busy. Retry later. */
request->status = TAPE_REQUEST_QUEUED;
schedule_work(&device->tape_dnr);
rc = 0;
} else {
/* Start failed. Remove request and indicate failure. */
DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
}
return rc;
}
static inline void
__tape_do_io_list(struct tape_device *device)
__tape_start_next_request(struct tape_device *device)
{
struct list_head *l, *n;
struct tape_request *request;
int rc;
DBF_LH(6, "__tape_do_io_list(%p)\n", device);
DBF_LH(6, "__tape_start_next_request(%p)\n", device);
/*
* Try to start each request on request queue until one is
* started successful.
*/
list_for_each_safe(l, n, &device->req_queue) {
request = list_entry(l, struct tape_request, list);
#ifdef CONFIG_S390_TAPE_BLOCK
if (request->op == TO_BLOCK)
device->discipline->check_locate(device, request);
#endif
rc = ccw_device_start(device->cdev, request->cpaddr,
(unsigned long) request, 0x00,
request->options);
if (rc == 0) {
request->status = TAPE_REQUEST_IN_IO;
break;
/*
* Avoid race condition if bottom-half was triggered more than
* once.
*/
if (request->status == TAPE_REQUEST_IN_IO)
return;
/*
* We wanted to cancel the request but the common I/O layer
* was busy at that time. This can only happen if this
* function is called by delayed_next_request.
* Otherwise we start the next request on the queue.
*/
if (request->status == TAPE_REQUEST_CANCEL) {
rc = __tape_cancel_io(device, request);
} else {
rc = __tape_start_io(device, request);
}
/* Start failed. Remove request and indicate failure. */
DBF_EVENT(1, "tape: DOIO failed with er = %i\n", rc);
if (rc == 0)
return;
/* Set ending status and do callback. */
/* Set ending status. */
request->rc = rc;
request->status = TAPE_REQUEST_DONE;
__tape_remove_request(device, request);
/* Remove from request queue. */
list_del(&request->list);
/* Do callback. */
if (request->callback != NULL)
request->callback(request, request->callback_data);
}
}
static void
__tape_remove_request(struct tape_device *device, struct tape_request *request)
tape_delayed_next_request(void *data)
{
/* Remove from request queue. */
list_del(&request->list);
struct tape_device * device;
/* Do callback. */
if (request->callback != NULL)
request->callback(request, request->callback_data);
device = (struct tape_device *) data;
DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
spin_lock_irq(get_ccwdev_lock(device->cdev));
__tape_start_next_request(device);
spin_unlock_irq(get_ccwdev_lock(device->cdev));
}
static inline void
__tape_end_request(
struct tape_device * device,
struct tape_request * request,
int rc)
{
DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
if (request) {
request->rc = rc;
request->status = TAPE_REQUEST_DONE;
/* Remove from request queue. */
list_del(&request->list);
/* Do callback. */
if (request->callback != NULL)
request->callback(request, request->callback_data);
}
/* Start next request. */
if (!list_empty(&device->req_queue))
__tape_do_io_list(device);
__tape_start_next_request(device);
}
/*
......@@ -812,7 +882,7 @@ tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
* the device lock held.
*/
static inline int
__tape_do_io(struct tape_device *device, struct tape_request *request)
__tape_start_request(struct tape_device *device, struct tape_request *request)
{
int rc;
......@@ -837,24 +907,16 @@ __tape_do_io(struct tape_device *device, struct tape_request *request)
if (list_empty(&device->req_queue)) {
/* No other requests are on the queue. Start this one. */
#ifdef CONFIG_S390_TAPE_BLOCK
if (request->op == TO_BLOCK)
device->discipline->check_locate(device, request);
#endif
rc = ccw_device_start(device->cdev, request->cpaddr,
(unsigned long) request, 0x00,
request->options);
if (rc) {
DBF_EVENT(1, "tape: DOIO failed with rc = %i\n", rc);
rc = __tape_start_io(device, request);
if (rc)
return rc;
}
DBF_LH(5, "Request %p added for execution.\n", request);
list_add(&request->list, &device->req_queue);
request->status = TAPE_REQUEST_IN_IO;
} else {
DBF_LH(5, "Request %p add to queue.\n", request);
list_add_tail(&request->list, &device->req_queue);
request->status = TAPE_REQUEST_QUEUED;
list_add_tail(&request->list, &device->req_queue);
}
return 0;
}
......@@ -872,7 +934,7 @@ tape_do_io_async(struct tape_device *device, struct tape_request *request)
spin_lock_irq(get_ccwdev_lock(device->cdev));
/* Add request to request queue and try to start it. */
rc = __tape_do_io(device, request);
rc = __tape_start_request(device, request);
spin_unlock_irq(get_ccwdev_lock(device->cdev));
return rc;
}
......@@ -901,7 +963,7 @@ tape_do_io(struct tape_device *device, struct tape_request *request)
request->callback = __tape_wake_up;
request->callback_data = &wq;
/* Add request to request queue and try to start it. */
rc = __tape_do_io(device, request);
rc = __tape_start_request(device, request);
spin_unlock_irq(get_ccwdev_lock(device->cdev));
if (rc)
return rc;
......@@ -935,7 +997,7 @@ tape_do_io_interruptible(struct tape_device *device,
/* Setup callback */
request->callback = __tape_wake_up_interruptible;
request->callback_data = &wq;
rc = __tape_do_io(device, request);
rc = __tape_start_request(device, request);
spin_unlock_irq(get_ccwdev_lock(device->cdev));
if (rc)
return rc;
......@@ -944,35 +1006,26 @@ tape_do_io_interruptible(struct tape_device *device,
if (rc != -ERESTARTSYS)
/* Request finished normally. */
return request->rc;
/* Interrupted by a signal. We have to stop the current request. */
spin_lock_irq(get_ccwdev_lock(device->cdev));
rc = __tape_halt_io(device, request);
rc = __tape_cancel_io(device, request);
spin_unlock_irq(get_ccwdev_lock(device->cdev));
if (rc == 0) {
/* Wait for the interrupt that acknowledges the halt. */
do {
rc = wait_event_interruptible(
wq,
(request->callback == NULL)
);
} while (rc != -ERESTARTSYS);
DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
rc = -ERESTARTSYS;
}
spin_unlock_irq(get_ccwdev_lock(device->cdev));
return rc;
}
/*
* Handle requests that return an i/o error in the irb.
*/
static inline void
tape_handle_killed_request(
struct tape_device *device,
struct tape_request *request)
{
if(request != NULL) {
/* Set ending status. FIXME: Should the request be retried? */
request->rc = -EIO;
request->status = TAPE_REQUEST_DONE;
__tape_remove_request(device, request);
} else {
__tape_do_io_list(device);
}
}
/*
* Tape interrupt routine, called from the ccw_device layer
*/
......@@ -981,7 +1034,6 @@ __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
{
struct tape_device *device;
struct tape_request *request;
int final;
int rc;
device = (struct tape_device *) cdev->dev.driver_data;
......@@ -996,12 +1048,13 @@ __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
/* On special conditions irb is an error pointer */
if (IS_ERR(irb)) {
/* FIXME: What to do with the request? */
switch (PTR_ERR(irb)) {
case -ETIMEDOUT:
PRINT_WARN("(%s): Request timed out\n",
cdev->dev.bus_id);
case -EIO:
tape_handle_killed_request(device, request);
__tape_end_request(device, request, -EIO);
break;
default:
PRINT_ERR("(%s): Unexpected i/o error %li\n",
......@@ -1011,6 +1064,21 @@ __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
return;
}
/*
* If the condition code is not zero and the start function bit is
* still set, this is an deferred error and the last start I/O did
* not succeed. Restart the request now.
*/
if (irb->scsw.cc != 0 && (irb->scsw.fctl & SCSW_FCTL_START_FUNC)) {
PRINT_WARN("(%s): deferred cc=%i. restaring\n",
cdev->dev.bus_id,
irb->scsw.cc);
rc = __tape_start_io(device, request);
if (rc)
__tape_end_request(device, request, rc);
return;
}
/* May be an unsolicited irq */
if(request != NULL)
request->rescnt = irb->scsw.count;
......@@ -1042,7 +1110,7 @@ __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
* To detect these request the state will be set to TAPE_REQUEST_DONE.
*/
if(request != NULL && request->status == TAPE_REQUEST_DONE) {
__tape_remove_request(device, request);
__tape_end_request(device, request, -EIO);
return;
}
......@@ -1054,51 +1122,34 @@ __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
* rc == TAPE_IO_RETRY: request finished but needs another go.
* rc == TAPE_IO_STOP: request needs to get terminated.
*/
final = 0;
switch (rc) {
case TAPE_IO_SUCCESS:
/* Upon normal completion the device _is_ online */
device->tape_generic_status |= GMT_ONLINE(~0);
final = 1;
break;
case TAPE_IO_PENDING:
break;
case TAPE_IO_RETRY:
#ifdef CONFIG_S390_TAPE_BLOCK
if (request->op == TO_BLOCK)
device->discipline->check_locate(device, request);
#endif
rc = ccw_device_start(cdev, request->cpaddr,
(unsigned long) request, 0x00,
request->options);
if (rc) {
DBF_EVENT(1, "tape: DOIO failed with er = %i\n", rc);
final = 1;
}
break;
case TAPE_IO_STOP:
__tape_halt_io(device, request);
break;
default:
if (rc > 0) {
DBF_EVENT(6, "xunknownrc\n");
PRINT_ERR("Invalid return code from discipline "
"interrupt function.\n");
rc = -EIO;
}
final = 1;
break;
}
if (final) {
/* May be an unsolicited irq */
if(request != NULL) {
/* Set ending status. */
request->rc = rc;
request->status = TAPE_REQUEST_DONE;
__tape_remove_request(device, request);
} else {
__tape_do_io_list(device);
}
case TAPE_IO_SUCCESS:
/* Upon normal completion the device _is_ online */
device->tape_generic_status |= GMT_ONLINE(~0);
__tape_end_request(device, request, rc);
break;
case TAPE_IO_PENDING:
break;
case TAPE_IO_RETRY:
rc = __tape_start_io(device, request);
if (rc)
__tape_end_request(device, request, rc);
break;
case TAPE_IO_STOP:
rc = __tape_cancel_io(device, request);
if (rc)
__tape_end_request(device, request, rc);
break;
default:
if (rc > 0) {
DBF_EVENT(6, "xunknownrc\n");
PRINT_ERR("Invalid return code from discipline "
"interrupt function.\n");
__tape_end_request(device, request, -EIO);
} else {
__tape_end_request(device, request, rc);
}
break;
}
}
......@@ -1191,7 +1242,7 @@ tape_init (void)
#ifdef DBF_LIKE_HELL
debug_set_level(TAPE_DBF_AREA, 6);
#endif
DBF_EVENT(3, "tape init: ($Revision: 1.51 $)\n");
DBF_EVENT(3, "tape init: ($Revision: 1.54 $)\n");
tape_proc_init();
tapechar_init ();
tapeblock_init ();
......@@ -1216,7 +1267,7 @@ tape_exit(void)
MODULE_AUTHOR("(C) 2001 IBM Deutschland Entwicklung GmbH by Carsten Otte and "
"Michael Holzheu (cotte@de.ibm.com,holzheu@de.ibm.com)");
MODULE_DESCRIPTION("Linux on zSeries channel attached "
"tape device driver ($Revision: 1.51 $)");
"tape device driver ($Revision: 1.54 $)");
MODULE_LICENSE("GPL");
module_init(tape_init);
......
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