From 1c1e093cbf6d3a7576ba0bd10363362a1c5c74ee Mon Sep 17 00:00:00 2001 From: Stefan Weinhuber Date: Wed, 12 May 2010 09:32:11 +0200 Subject: [S390] dasd: fix race between tasklet and dasd_sleep_on The various dasd_sleep_on functions use a global wait queue when waiting for a cqr. The wait condition checks the status and devlist fields of the cqr to determine if it is safe to continue. This evaluation may return true, although the tasklet has not finished processing of the cqr and the callback function has not been called yet. When the callback is finally called, the data in the cqr may already be invalid. The sleep_on wait condition needs a safe way to determine if the tasklet has finished processing. Use the callback_data field of the cqr to store a token, which is set by the callback function itself. Cc: Signed-off-by: Stefan Weinhuber Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- drivers/s390/block/dasd.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'drivers/s390/block/dasd.c') diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index acf222f91f5a..fa2339cb1681 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -37,6 +37,9 @@ */ #define DASD_CHANQ_MAX_SIZE 4 +#define DASD_SLEEPON_START_TAG (void *) 1 +#define DASD_SLEEPON_END_TAG (void *) 2 + /* * SECTION: exported variables of dasd.c */ @@ -1472,7 +1475,10 @@ void dasd_add_request_tail(struct dasd_ccw_req *cqr) */ static void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data) { - wake_up((wait_queue_head_t *) data); + spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev)); + cqr->callback_data = DASD_SLEEPON_END_TAG; + spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev)); + wake_up(&generic_waitq); } static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr) @@ -1482,10 +1488,7 @@ static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr) device = cqr->startdev; spin_lock_irq(get_ccwdev_lock(device->cdev)); - rc = ((cqr->status == DASD_CQR_DONE || - cqr->status == DASD_CQR_NEED_ERP || - cqr->status == DASD_CQR_TERMINATED) && - list_empty(&cqr->devlist)); + rc = (cqr->callback_data == DASD_SLEEPON_END_TAG); spin_unlock_irq(get_ccwdev_lock(device->cdev)); return rc; } @@ -1573,7 +1576,7 @@ static int _dasd_sleep_on(struct dasd_ccw_req *maincqr, int interruptible) wait_event(generic_waitq, !(device->stopped)); cqr->callback = dasd_wakeup_cb; - cqr->callback_data = (void *) &generic_waitq; + cqr->callback_data = DASD_SLEEPON_START_TAG; dasd_add_request_tail(cqr); if (interruptible) { rc = wait_event_interruptible( @@ -1652,7 +1655,7 @@ int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr) } cqr->callback = dasd_wakeup_cb; - cqr->callback_data = (void *) &generic_waitq; + cqr->callback_data = DASD_SLEEPON_START_TAG; cqr->status = DASD_CQR_QUEUED; list_add(&cqr->devlist, &device->ccw_queue); -- cgit v1.2.3 From 501183f2ed74434e30a1b039b2f3af30f1f3f461 Mon Sep 17 00:00:00 2001 From: Stefan Haberland Date: Mon, 17 May 2010 10:00:10 +0200 Subject: [S390] dasd: add dynamic pav toleration For base Parallel Access Volume (PAV) there is a fixed mapping of base and alias devices. With dynamic PAV this mapping can be changed so that an alias device is used with another base device. This patch enables the DASD device driver to tolerate dynamic PAV changes. Signed-off-by: Stefan Haberland Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- drivers/s390/block/dasd.c | 22 ++++++++++++ drivers/s390/block/dasd_3990_erp.c | 20 +++++++++++ drivers/s390/block/dasd_alias.c | 8 +++++ drivers/s390/block/dasd_eckd.c | 70 ++++++++++++++++++++++++++++++++++++-- drivers/s390/block/dasd_eckd.h | 2 +- drivers/s390/block/dasd_int.h | 5 +++ 6 files changed, 124 insertions(+), 3 deletions(-) (limited to 'drivers/s390/block/dasd.c') diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index fa2339cb1681..0e86247d791e 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -65,6 +65,7 @@ static void dasd_device_tasklet(struct dasd_device *); static void dasd_block_tasklet(struct dasd_block *); static void do_kick_device(struct work_struct *); static void do_restore_device(struct work_struct *); +static void do_reload_device(struct work_struct *); static void dasd_return_cqr_cb(struct dasd_ccw_req *, void *); static void dasd_device_timeout(unsigned long); static void dasd_block_timeout(unsigned long); @@ -115,6 +116,7 @@ struct dasd_device *dasd_alloc_device(void) device->timer.data = (unsigned long) device; INIT_WORK(&device->kick_work, do_kick_device); INIT_WORK(&device->restore_device, do_restore_device); + INIT_WORK(&device->reload_device, do_reload_device); device->state = DASD_STATE_NEW; device->target = DASD_STATE_NEW; mutex_init(&device->state_mutex); @@ -520,6 +522,26 @@ void dasd_kick_device(struct dasd_device *device) schedule_work(&device->kick_work); } +/* + * dasd_reload_device will schedule a call do do_reload_device to the kernel + * event daemon. + */ +static void do_reload_device(struct work_struct *work) +{ + struct dasd_device *device = container_of(work, struct dasd_device, + reload_device); + device->discipline->reload(device); + dasd_put_device(device); +} + +void dasd_reload_device(struct dasd_device *device) +{ + dasd_get_device(device); + /* queue call to dasd_reload_device to the kernel event daemon. */ + schedule_work(&device->reload_device); +} +EXPORT_SYMBOL(dasd_reload_device); + /* * dasd_restore_device will schedule a call do do_restore_device to the kernel * event daemon. diff --git a/drivers/s390/block/dasd_3990_erp.c b/drivers/s390/block/dasd_3990_erp.c index 6632649dd6aa..85bfd8794856 100644 --- a/drivers/s390/block/dasd_3990_erp.c +++ b/drivers/s390/block/dasd_3990_erp.c @@ -1418,9 +1418,29 @@ static struct dasd_ccw_req *dasd_3990_erp_inspect_alias( struct dasd_ccw_req *erp) { struct dasd_ccw_req *cqr = erp->refers; + char *sense; if (cqr->block && (cqr->block->base != cqr->startdev)) { + + sense = dasd_get_sense(&erp->refers->irb); + /* + * dynamic pav may have changed base alias mapping + */ + if (!test_bit(DASD_FLAG_OFFLINE, &cqr->startdev->flags) && sense + && (sense[0] == 0x10) && (sense[7] == 0x0F) + && (sense[8] == 0x67)) { + /* + * remove device from alias handling to prevent new + * requests from being scheduled on the + * wrong alias device + */ + dasd_alias_remove_device(cqr->startdev); + + /* schedule worker to reload device */ + dasd_reload_device(cqr->startdev); + } + if (cqr->startdev->features & DASD_FEATURE_ERPLOG) { DBF_DEV_EVENT(DBF_ERR, cqr->startdev, "ERP on alias device for request %p," diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c index 8c4814258e93..a564b9941114 100644 --- a/drivers/s390/block/dasd_alias.c +++ b/drivers/s390/block/dasd_alias.c @@ -642,6 +642,14 @@ int dasd_alias_add_device(struct dasd_device *device) return rc; } +int dasd_alias_update_add_device(struct dasd_device *device) +{ + struct dasd_eckd_private *private; + private = (struct dasd_eckd_private *) device->private; + private->lcu->flags |= UPDATE_PENDING; + return dasd_alias_add_device(device); +} + int dasd_alias_remove_device(struct dasd_device *device) { struct dasd_eckd_private *private; diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c index 0cb233116855..4305c23c57a4 100644 --- a/drivers/s390/block/dasd_eckd.c +++ b/drivers/s390/block/dasd_eckd.c @@ -1451,6 +1451,7 @@ static int dasd_eckd_ready_to_online(struct dasd_device *device) static int dasd_eckd_online_to_ready(struct dasd_device *device) { + cancel_work_sync(&device->reload_device); return dasd_alias_remove_device(device); }; @@ -1709,10 +1710,27 @@ static void dasd_eckd_handle_unsolicited_interrupt(struct dasd_device *device, { char mask; char *sense = NULL; + struct dasd_eckd_private *private; + private = (struct dasd_eckd_private *) device->private; /* first of all check for state change pending interrupt */ mask = DEV_STAT_ATTENTION | DEV_STAT_DEV_END | DEV_STAT_UNIT_EXCEP; if ((scsw_dstat(&irb->scsw) & mask) == mask) { + /* for alias only and not in offline processing*/ + if (!device->block && private->lcu && + !test_bit(DASD_FLAG_OFFLINE, &device->flags)) { + /* + * the state change could be caused by an alias + * reassignment remove device from alias handling + * to prevent new requests from being scheduled on + * the wrong alias device + */ + dasd_alias_remove_device(device); + + /* schedule worker to reload device */ + dasd_reload_device(device); + } + dasd_generic_handle_state_change(device); return; } @@ -3259,7 +3277,7 @@ static void dasd_eckd_dump_sense(struct dasd_device *device, dasd_eckd_dump_sense_ccw(device, req, irb); } -int dasd_eckd_pm_freeze(struct dasd_device *device) +static int dasd_eckd_pm_freeze(struct dasd_device *device) { /* * the device should be disconnected from our LCU structure @@ -3272,7 +3290,7 @@ int dasd_eckd_pm_freeze(struct dasd_device *device) return 0; } -int dasd_eckd_restore_device(struct dasd_device *device) +static int dasd_eckd_restore_device(struct dasd_device *device) { struct dasd_eckd_private *private; struct dasd_eckd_characteristics temp_rdc_data; @@ -3336,6 +3354,53 @@ out_err: return -1; } +static int dasd_eckd_reload_device(struct dasd_device *device) +{ + struct dasd_eckd_private *private; + int rc, old_base; + char uid[60]; + + private = (struct dasd_eckd_private *) device->private; + old_base = private->uid.base_unit_addr; + /* Read Configuration Data */ + rc = dasd_eckd_read_conf(device); + if (rc) + goto out_err; + + rc = dasd_eckd_generate_uid(device, &private->uid); + if (rc) + goto out_err; + + dasd_set_uid(device->cdev, &private->uid); + + /* + * update unit address configuration and + * add device to alias management + */ + dasd_alias_update_add_device(device); + + if (old_base != private->uid.base_unit_addr) { + if (strlen(private->uid.vduit) > 0) + snprintf(uid, 60, "%s.%s.%04x.%02x.%s", + private->uid.vendor, private->uid.serial, + private->uid.ssid, private->uid.base_unit_addr, + private->uid.vduit); + else + snprintf(uid, 60, "%s.%s.%04x.%02x", + private->uid.vendor, private->uid.serial, + private->uid.ssid, + private->uid.base_unit_addr); + + dev_info(&device->cdev->dev, + "An Alias device was reassigned to a new base device " + "with UID: %s\n", uid); + } + return 0; + +out_err: + return -1; +} + static struct ccw_driver dasd_eckd_driver = { .name = "dasd-eckd", .owner = THIS_MODULE, @@ -3389,6 +3454,7 @@ static struct dasd_discipline dasd_eckd_discipline = { .ioctl = dasd_eckd_ioctl, .freeze = dasd_eckd_pm_freeze, .restore = dasd_eckd_restore_device, + .reload = dasd_eckd_reload_device, }; static int __init diff --git a/drivers/s390/block/dasd_eckd.h b/drivers/s390/block/dasd_eckd.h index 864d53c04201..dd6385a5af14 100644 --- a/drivers/s390/block/dasd_eckd.h +++ b/drivers/s390/block/dasd_eckd.h @@ -426,7 +426,6 @@ struct alias_pav_group { struct dasd_device *next; }; - struct dasd_eckd_private { struct dasd_eckd_characteristics rdc_data; u8 *conf_data; @@ -463,4 +462,5 @@ void dasd_alias_handle_summary_unit_check(struct dasd_device *, struct irb *); void dasd_eckd_reset_ccw_to_base_io(struct dasd_ccw_req *); void dasd_alias_lcu_setup_complete(struct dasd_device *); void dasd_alias_wait_for_lcu_setup(struct dasd_device *); +int dasd_alias_update_add_device(struct dasd_device *); #endif /* DASD_ECKD_H */ diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h index a91d4a97d4f2..1ae7b121628e 100644 --- a/drivers/s390/block/dasd_int.h +++ b/drivers/s390/block/dasd_int.h @@ -312,6 +312,9 @@ struct dasd_discipline { /* suspend/resume functions */ int (*freeze) (struct dasd_device *); int (*restore) (struct dasd_device *); + + /* reload device after state change */ + int (*reload) (struct dasd_device *); }; extern struct dasd_discipline *dasd_diag_discipline_pointer; @@ -386,6 +389,7 @@ struct dasd_device { struct tasklet_struct tasklet; struct work_struct kick_work; struct work_struct restore_device; + struct work_struct reload_device; struct timer_list timer; debug_info_t *debug_area; @@ -582,6 +586,7 @@ void dasd_enable_device(struct dasd_device *); void dasd_set_target_state(struct dasd_device *, int); void dasd_kick_device(struct dasd_device *); void dasd_restore_device(struct dasd_device *); +void dasd_reload_device(struct dasd_device *); void dasd_add_request_head(struct dasd_ccw_req *); void dasd_add_request_tail(struct dasd_ccw_req *); -- cgit v1.2.3