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Subject[patch] s390: dasd offline processing.
From: Horst Hummel <horst.hummel@de.ibm.com>

[S390] dasd offline processing.

Fix clear_IO handling (need to wait for interrupt) and
introduced error-handling in shutdown processing.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

drivers/s390/block/dasd.c | 192 +++++++++++++++++++++++++++-------------
drivers/s390/block/dasd_genhd.c | 10 +-
2 files changed, 137 insertions(+), 65 deletions(-)

diff -urpN linux-2.6/drivers/s390/block/dasd.c linux-2.6-patched/drivers/s390/block/dasd.c
--- linux-2.6/drivers/s390/block/dasd.c 2006-08-24 12:09:53.000000000 +0200
+++ linux-2.6-patched/drivers/s390/block/dasd.c 2006-08-24 12:10:52.000000000 +0200
@@ -52,7 +52,7 @@ static void dasd_setup_queue(struct dasd
static void dasd_free_queue(struct dasd_device * device);
static void dasd_flush_request_queue(struct dasd_device *);
static void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
-static void dasd_flush_ccw_queue(struct dasd_device *, int);
+static int dasd_flush_ccw_queue(struct dasd_device *, int);
static void dasd_tasklet(struct dasd_device *);
static void do_kick_device(void *data);

@@ -60,6 +60,7 @@ static void do_kick_device(void *data);
* SECTION: Operations on the device structure.
*/
static wait_queue_head_t dasd_init_waitq;
+static wait_queue_head_t dasd_flush_wq;

/*
* Allocate memory for a new device structure.
@@ -121,7 +122,7 @@ dasd_free_device(struct dasd_device *dev
/*
* Make a new device known to the system.
*/
-static inline int
+static int
dasd_state_new_to_known(struct dasd_device *device)
{
int rc;
@@ -145,7 +146,7 @@ dasd_state_new_to_known(struct dasd_devi
/*
* Let the system forget about a device.
*/
-static inline void
+static int
dasd_state_known_to_new(struct dasd_device * device)
{
/* Disable extended error reporting for this device. */
@@ -163,12 +164,13 @@ dasd_state_known_to_new(struct dasd_devi

/* Give up reference we took in dasd_state_new_to_known. */
dasd_put_device(device);
+ return 0;
}

/*
* Request the irq line for the device.
*/
-static inline int
+static int
dasd_state_known_to_basic(struct dasd_device * device)
{
int rc;
@@ -192,17 +194,23 @@ dasd_state_known_to_basic(struct dasd_de
/*
* Release the irq line for the device. Terminate any running i/o.
*/
-static inline void
+static int
dasd_state_basic_to_known(struct dasd_device * device)
{
+ int rc;
+
dasd_gendisk_free(device);
- dasd_flush_ccw_queue(device, 1);
+ rc = dasd_flush_ccw_queue(device, 1);
+ if (rc)
+ return rc;
+
DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
if (device->debug_area != NULL) {
debug_unregister(device->debug_area);
device->debug_area = NULL;
}
device->state = DASD_STATE_KNOWN;
+ return 0;
}

/*
@@ -219,7 +227,7 @@ dasd_state_basic_to_known(struct dasd_de
* In case the analysis returns an error, the device setup is stopped
* (a fake disk was already added to allow formatting).
*/
-static inline int
+static int
dasd_state_basic_to_ready(struct dasd_device * device)
{
int rc;
@@ -247,25 +255,31 @@ dasd_state_basic_to_ready(struct dasd_de
* Forget format information. Check if the target level is basic
* and if it is create fake disk for formatting.
*/
-static inline void
+static int
dasd_state_ready_to_basic(struct dasd_device * device)
{
- dasd_flush_ccw_queue(device, 0);
+ int rc;
+
+ rc = dasd_flush_ccw_queue(device, 0);
+ if (rc)
+ return rc;
dasd_destroy_partitions(device);
dasd_flush_request_queue(device);
device->blocks = 0;
device->bp_block = 0;
device->s2b_shift = 0;
device->state = DASD_STATE_BASIC;
+ return 0;
}

/*
* Back to basic.
*/
-static inline void
+static int
dasd_state_unfmt_to_basic(struct dasd_device * device)
{
device->state = DASD_STATE_BASIC;
+ return 0;
}

/*
@@ -273,7 +287,7 @@ dasd_state_unfmt_to_basic(struct dasd_de
* the requeueing of requests from the linux request queue to the
* ccw queue.
*/
-static inline int
+static int
dasd_state_ready_to_online(struct dasd_device * device)
{
device->state = DASD_STATE_ONLINE;
@@ -284,16 +298,17 @@ dasd_state_ready_to_online(struct dasd_d
/*
* Stop the requeueing of requests again.
*/
-static inline void
+static int
dasd_state_online_to_ready(struct dasd_device * device)
{
device->state = DASD_STATE_READY;
+ return 0;
}

/*
* Device startup state changes.
*/
-static inline int
+static int
dasd_increase_state(struct dasd_device *device)
{
int rc;
@@ -329,30 +344,37 @@ dasd_increase_state(struct dasd_device *
/*
* Device shutdown state changes.
*/
-static inline int
+static int
dasd_decrease_state(struct dasd_device *device)
{
+ int rc;
+
+ rc = 0;
if (device->state == DASD_STATE_ONLINE &&
device->target <= DASD_STATE_READY)
- dasd_state_online_to_ready(device);
+ rc = dasd_state_online_to_ready(device);

- if (device->state == DASD_STATE_READY &&
+ if (!rc &&
+ device->state == DASD_STATE_READY &&
device->target <= DASD_STATE_BASIC)
- dasd_state_ready_to_basic(device);
+ rc = dasd_state_ready_to_basic(device);

- if (device->state == DASD_STATE_UNFMT &&
+ if (!rc &&
+ device->state == DASD_STATE_UNFMT &&
device->target <= DASD_STATE_BASIC)
- dasd_state_unfmt_to_basic(device);
+ rc = dasd_state_unfmt_to_basic(device);

- if (device->state == DASD_STATE_BASIC &&
+ if (!rc &&
+ device->state == DASD_STATE_BASIC &&
device->target <= DASD_STATE_KNOWN)
- dasd_state_basic_to_known(device);
+ rc = dasd_state_basic_to_known(device);

- if (device->state == DASD_STATE_KNOWN &&
+ if (!rc &&
+ device->state == DASD_STATE_KNOWN &&
device->target <= DASD_STATE_NEW)
- dasd_state_known_to_new(device);
+ rc = dasd_state_known_to_new(device);

- return 0;
+ return rc;
}

/*
@@ -701,6 +723,7 @@ dasd_term_IO(struct dasd_ccw_req * cqr)
cqr->retries--;
cqr->status = DASD_CQR_CLEAR;
cqr->stopclk = get_clock();
+ cqr->starttime = 0;
DBF_DEV_EVENT(DBF_DEBUG, device,
"terminate cqr %p successful",
cqr);
@@ -978,6 +1001,7 @@ dasd_int_handler(struct ccw_device *cdev
irb->scsw.fctl & SCSW_FCTL_CLEAR_FUNC) {
cqr->status = DASD_CQR_QUEUED;
dasd_clear_timer(device);
+ wake_up(&dasd_flush_wq);
dasd_schedule_bh(device);
return;
}
@@ -1241,6 +1265,10 @@ __dasd_check_expire(struct dasd_device *
cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
if (cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) {
if (time_after_eq(jiffies, cqr->expires + cqr->starttime)) {
+ DEV_MESSAGE(KERN_ERR, device,
+ "internal error - timeout (%is) expired "
+ "for cqr %p (%i retries left)",
+ (cqr->expires/HZ), cqr, cqr->retries);
if (device->discipline->term_IO(cqr) != 0)
/* Hmpf, try again in 1/10 sec */
dasd_set_timer(device, 10);
@@ -1285,46 +1313,100 @@ __dasd_start_head(struct dasd_device * d
dasd_set_timer(device, 50);
}

+static inline int
+_wait_for_clear(struct dasd_ccw_req *cqr)
+{
+ return (cqr->status == DASD_CQR_QUEUED);
+}
+
/*
- * Remove requests from the ccw queue.
+ * Remove all requests from the ccw queue (all = '1') or only block device
+ * requests in case all = '0'.
+ * Take care of the erp-chain (chained via cqr->refers) and remove either
+ * the whole erp-chain or none of the erp-requests.
+ * If a request is currently running, term_IO is called and the request
+ * is re-queued. Prior to removing the terminated request we need to wait
+ * for the clear-interrupt.
+ * In case termination is not possible we stop processing and just finishing
+ * the already moved requests.
*/
-static void
+static int
dasd_flush_ccw_queue(struct dasd_device * device, int all)
{
+ struct dasd_ccw_req *cqr, *orig, *n;
+ int rc, i;
+
struct list_head flush_queue;
- struct list_head *l, *n;
- struct dasd_ccw_req *cqr;

INIT_LIST_HEAD(&flush_queue);
spin_lock_irq(get_ccwdev_lock(device->cdev));
- list_for_each_safe(l, n, &device->ccw_queue) {
- cqr = list_entry(l, struct dasd_ccw_req, list);
+ rc = 0;
+restart:
+ list_for_each_entry_safe(cqr, n, &device->ccw_queue, list) {
+ /* get original request of erp request-chain */
+ for (orig = cqr; orig->refers != NULL; orig = orig->refers);
+
/* Flush all request or only block device requests? */
- if (all == 0 && cqr->callback == dasd_end_request_cb)
+ if (all == 0 && cqr->callback != dasd_end_request_cb &&
+ orig->callback != dasd_end_request_cb) {
continue;
- if (cqr->status == DASD_CQR_IN_IO)
- device->discipline->term_IO(cqr);
- if (cqr->status != DASD_CQR_DONE ||
- cqr->status != DASD_CQR_FAILED) {
- cqr->status = DASD_CQR_FAILED;
+ }
+ /* Check status and move request to flush_queue */
+ switch (cqr->status) {
+ case DASD_CQR_IN_IO:
+ rc = device->discipline->term_IO(cqr);
+ if (rc) {
+ /* unable to terminate requeust */
+ DEV_MESSAGE(KERN_ERR, device,
+ "dasd flush ccw_queue is unable "
+ " to terminate request %p",
+ cqr);
+ /* stop flush processing */
+ goto finished;
+ }
+ break;
+ case DASD_CQR_QUEUED:
+ case DASD_CQR_ERROR:
+ /* set request to FAILED */
cqr->stopclk = get_clock();
+ cqr->status = DASD_CQR_FAILED;
+ break;
+ default: /* do not touch the others */
+ break;
+ }
+ /* Rechain request (including erp chain) */
+ for (i = 0; cqr != NULL; cqr = cqr->refers, i++) {
+ cqr->endclk = get_clock();
+ list_move_tail(&cqr->list, &flush_queue);
+ }
+ if (i > 1)
+ /* moved more than one request - need to restart */
+ goto restart;
+ }
+
+finished:
+ spin_unlock_irq(get_ccwdev_lock(device->cdev));
+ /* Now call the callback function of flushed requests */
+restart_cb:
+ list_for_each_entry_safe(cqr, n, &flush_queue, list) {
+ if (cqr->status == DASD_CQR_CLEAR) {
+ /* wait for clear interrupt! */
+ wait_event(dasd_flush_wq, _wait_for_clear(cqr));
+ cqr->status = DASD_CQR_FAILED;
}
/* Process finished ERP request. */
if (cqr->refers) {
__dasd_process_erp(device, cqr);
- continue;
+ /* restart list_for_xx loop since dasd_process_erp
+ * might remove multiple elements */
+ goto restart_cb;
}
- /* Rechain request on device request queue */
+ /* call the callback function */
cqr->endclk = get_clock();
- list_move_tail(&cqr->list, &flush_queue);
- }
- spin_unlock_irq(get_ccwdev_lock(device->cdev));
- /* Now call the callback function of flushed requests */
- list_for_each_safe(l, n, &flush_queue) {
- cqr = list_entry(l, struct dasd_ccw_req, list);
if (cqr->callback != NULL)
(cqr->callback)(cqr, cqr->callback_data);
}
+ return rc;
}

/*
@@ -1510,10 +1592,8 @@ dasd_sleep_on_interruptible(struct dasd_
if (device->discipline->term_IO) {
cqr->retries = -1;
device->discipline->term_IO(cqr);
- /*nished =
- * wait (non-interruptible) for final status
- * because signal ist still pending
- */
+ /* wait (non-interruptible) for final status
+ * because signal ist still pending */
spin_unlock_irq(get_ccwdev_lock(device->cdev));
wait_event(wait_q, _wait_for_wakeup(cqr));
spin_lock_irq(get_ccwdev_lock(device->cdev));
@@ -1546,19 +1626,11 @@ static inline int
_dasd_term_running_cqr(struct dasd_device *device)
{
struct dasd_ccw_req *cqr;
- int rc;

if (list_empty(&device->ccw_queue))
return 0;
cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
- rc = device->discipline->term_IO(cqr);
- if (rc == 0) {
- /* termination successful */
- cqr->status = DASD_CQR_QUEUED;
- cqr->startclk = cqr->stopclk = 0;
- cqr->starttime = 0;
- }
- return rc;
+ return device->discipline->term_IO(cqr);
}

int
@@ -1726,10 +1798,7 @@ dasd_flush_request_queue(struct dasd_dev
return;

spin_lock_irq(&device->request_queue_lock);
- while (!list_empty(&device->request_queue->queue_head)) {
- req = elv_next_request(device->request_queue);
- if (req == NULL)
- break;
+ while ((req = elv_next_request(device->request_queue))) {
blkdev_dequeue_request(req);
dasd_end_request(req, 0);
}
@@ -2091,6 +2160,7 @@ dasd_init(void)
int rc;

init_waitqueue_head(&dasd_init_waitq);
+ init_waitqueue_head(&dasd_flush_wq);

/* register 'common' DASD debug area, used for all DBF_XXX calls */
dasd_debug_area = debug_register("dasd", 1, 2, 8 * sizeof (long));
diff -urpN linux-2.6/drivers/s390/block/dasd_genhd.c linux-2.6-patched/drivers/s390/block/dasd_genhd.c
--- linux-2.6/drivers/s390/block/dasd_genhd.c 2006-08-24 12:09:53.000000000 +0200
+++ linux-2.6-patched/drivers/s390/block/dasd_genhd.c 2006-08-24 12:10:52.000000000 +0200
@@ -83,10 +83,12 @@ dasd_gendisk_alloc(struct dasd_device *d
void
dasd_gendisk_free(struct dasd_device *device)
{
- del_gendisk(device->gdp);
- device->gdp->queue = NULL;
- put_disk(device->gdp);
- device->gdp = NULL;
+ if (device->gdp) {
+ del_gendisk(device->gdp);
+ device->gdp->queue = NULL;
+ put_disk(device->gdp);
+ device->gdp = NULL;
+ }
}

/*
-
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