From 5db45bdc87ce4f503947adf7896586d60c63322c Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 21 Jun 2012 23:30:48 -0700 Subject: [PATCH] [SCSI] libsas: enforce eh strategy handlers only in eh context The strategy handlers may be called in places that are problematic for libsas (i.e. sata resets outside of domain revalidation filtering / libata link recovery), or problematic for userspace (non-blocking ioctl to sleeping reset functions). However, these routines are also called for eh escalations and recovery of scsi_eh_prep_cmnd(), so permit them as long as we are running in the host's error handler, otherwise arrange for them to be triggered in eh_context. Signed-off-by: Dan Williams Signed-off-by: James Bottomley --- drivers/scsi/libsas/sas_discover.c | 11 ++++ drivers/scsi/libsas/sas_init.c | 2 + drivers/scsi/libsas/sas_scsi_host.c | 121 ++++++++++++++++++++++++++++++++++-- include/scsi/libsas.h | 10 +++ 4 files changed, 140 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c index ff497ac..b031d23 100644 --- a/drivers/scsi/libsas/sas_discover.c +++ b/drivers/scsi/libsas/sas_discover.c @@ -39,6 +39,7 @@ void sas_init_dev(struct domain_device *dev) { switch (dev->dev_type) { case SAS_END_DEV: + INIT_LIST_HEAD(&dev->ssp_dev.eh_list_node); break; case EDGE_DEV: case FANOUT_DEV: @@ -286,6 +287,8 @@ void sas_free_device(struct kref *kref) static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_device *dev) { + struct sas_ha_struct *ha = port->ha; + sas_notify_lldd_dev_gone(dev); if (!dev->parent) dev->port->port_dev = NULL; @@ -298,6 +301,14 @@ static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_d sas_ata_end_eh(dev->sata_dev.ap); spin_unlock_irq(&port->dev_list_lock); + spin_lock_irq(&ha->lock); + if (dev->dev_type == SAS_END_DEV && + !list_empty(&dev->ssp_dev.eh_list_node)) { + list_del_init(&dev->ssp_dev.eh_list_node); + ha->eh_active--; + } + spin_unlock_irq(&ha->lock); + sas_put_device(dev); } diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c index 6909fef..1bbab3d 100644 --- a/drivers/scsi/libsas/sas_init.c +++ b/drivers/scsi/libsas/sas_init.c @@ -116,7 +116,9 @@ int sas_register_ha(struct sas_ha_struct *sas_ha) set_bit(SAS_HA_REGISTERED, &sas_ha->state); spin_lock_init(&sas_ha->lock); mutex_init(&sas_ha->drain_mutex); + init_waitqueue_head(&sas_ha->eh_wait_q); INIT_LIST_HEAD(&sas_ha->defer_q); + INIT_LIST_HEAD(&sas_ha->eh_dev_q); error = sas_register_phys(sas_ha); if (error) { diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c index 52d5b01..2e0e779 100644 --- a/drivers/scsi/libsas/sas_scsi_host.c +++ b/drivers/scsi/libsas/sas_scsi_host.c @@ -460,14 +460,88 @@ struct sas_phy *sas_get_local_phy(struct domain_device *dev) } EXPORT_SYMBOL_GPL(sas_get_local_phy); +static void sas_wait_eh(struct domain_device *dev) +{ + struct sas_ha_struct *ha = dev->port->ha; + DEFINE_WAIT(wait); + + if (dev_is_sata(dev)) { + ata_port_wait_eh(dev->sata_dev.ap); + return; + } + retry: + spin_lock_irq(&ha->lock); + + while (test_bit(SAS_DEV_EH_PENDING, &dev->state)) { + prepare_to_wait(&ha->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE); + spin_unlock_irq(&ha->lock); + schedule(); + spin_lock_irq(&ha->lock); + } + finish_wait(&ha->eh_wait_q, &wait); + + spin_unlock_irq(&ha->lock); + + /* make sure SCSI EH is complete */ + if (scsi_host_in_recovery(ha->core.shost)) { + msleep(10); + goto retry; + } +} +EXPORT_SYMBOL(sas_wait_eh); + +static int sas_queue_reset(struct domain_device *dev, int reset_type, int lun, int wait) +{ + struct sas_ha_struct *ha = dev->port->ha; + int scheduled = 0, tries = 100; + + /* ata: promote lun reset to bus reset */ + if (dev_is_sata(dev)) { + sas_ata_schedule_reset(dev); + if (wait) + sas_ata_wait_eh(dev); + return SUCCESS; + } + + while (!scheduled && tries--) { + spin_lock_irq(&ha->lock); + if (!test_bit(SAS_DEV_EH_PENDING, &dev->state) && + !test_bit(reset_type, &dev->state)) { + scheduled = 1; + ha->eh_active++; + list_add_tail(&dev->ssp_dev.eh_list_node, &ha->eh_dev_q); + set_bit(SAS_DEV_EH_PENDING, &dev->state); + set_bit(reset_type, &dev->state); + int_to_scsilun(lun, &dev->ssp_dev.reset_lun); + scsi_schedule_eh(ha->core.shost); + } + spin_unlock_irq(&ha->lock); + + if (wait) + sas_wait_eh(dev); + + if (scheduled) + return SUCCESS; + } + + SAS_DPRINTK("%s reset of %s failed\n", + reset_type == SAS_DEV_LU_RESET ? "LUN" : "Bus", + dev_name(&dev->rphy->dev)); + + return FAILED; +} + /* Attempt to send a LUN reset message to a device */ int sas_eh_device_reset_handler(struct scsi_cmnd *cmd) { - struct domain_device *dev = cmd_to_domain_dev(cmd); - struct sas_internal *i = - to_sas_internal(dev->port->ha->core.shost->transportt); - struct scsi_lun lun; int res; + struct scsi_lun lun; + struct Scsi_Host *host = cmd->device->host; + struct domain_device *dev = cmd_to_domain_dev(cmd); + struct sas_internal *i = to_sas_internal(host->transportt); + + if (current != host->ehandler) + return sas_queue_reset(dev, SAS_DEV_LU_RESET, cmd->device->lun, 0); int_to_scsilun(cmd->device->lun, &lun); @@ -486,8 +560,12 @@ int sas_eh_bus_reset_handler(struct scsi_cmnd *cmd) { struct domain_device *dev = cmd_to_domain_dev(cmd); struct sas_phy *phy = sas_get_local_phy(dev); + struct Scsi_Host *host = cmd->device->host; int res; + if (current != host->ehandler) + return sas_queue_reset(dev, SAS_DEV_RESET, 0, 0); + res = sas_phy_reset(phy, 1); if (res) SAS_DPRINTK("Bus reset of %s failed 0x%x\n", @@ -667,6 +745,39 @@ static void sas_eh_handle_sas_errors(struct Scsi_Host *shost, struct list_head * goto out; } +static void sas_eh_handle_resets(struct Scsi_Host *shost) +{ + struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost); + struct sas_internal *i = to_sas_internal(shost->transportt); + + /* handle directed resets to sas devices */ + spin_lock_irq(&ha->lock); + while (!list_empty(&ha->eh_dev_q)) { + struct domain_device *dev; + struct ssp_device *ssp; + + ssp = list_entry(ha->eh_dev_q.next, typeof(*ssp), eh_list_node); + list_del_init(&ssp->eh_list_node); + dev = container_of(ssp, typeof(*dev), ssp_dev); + kref_get(&dev->kref); + WARN_ONCE(dev_is_sata(dev), "ssp reset to ata device?\n"); + + spin_unlock_irq(&ha->lock); + + if (test_and_clear_bit(SAS_DEV_LU_RESET, &dev->state)) + i->dft->lldd_lu_reset(dev, ssp->reset_lun.scsi_lun); + + if (test_and_clear_bit(SAS_DEV_RESET, &dev->state)) + i->dft->lldd_I_T_nexus_reset(dev); + + sas_put_device(dev); + spin_lock_irq(&ha->lock); + clear_bit(SAS_DEV_EH_PENDING, &dev->state); + ha->eh_active--; + } + spin_unlock_irq(&ha->lock); +} + void sas_scsi_recover_host(struct Scsi_Host *shost) { @@ -709,6 +820,8 @@ out: if (ha->lldd_max_execute_num > 1) wake_up_process(ha->core.queue_thread); + sas_eh_handle_resets(shost); + /* now link into libata eh --- if we have any ata devices */ sas_ata_strategy_handler(shost); diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h index 814d8cb..df9cefd 100644 --- a/include/scsi/libsas.h +++ b/include/scsi/libsas.h @@ -176,10 +176,17 @@ struct sata_device { u8 fis[ATA_RESP_FIS_SIZE]; }; +struct ssp_device { + struct list_head eh_list_node; /* pending a user requested eh action */ + struct scsi_lun reset_lun; +}; + enum { SAS_DEV_GONE, SAS_DEV_DESTROY, SAS_DEV_EH_PENDING, + SAS_DEV_LU_RESET, + SAS_DEV_RESET, }; struct domain_device { @@ -213,6 +220,7 @@ struct domain_device { union { struct expander_device ex_dev; struct sata_device sata_dev; /* STP & directly attached */ + struct ssp_device ssp_dev; }; void *lldd_dev; @@ -389,6 +397,8 @@ struct sas_ha_struct { unsigned long state; spinlock_t lock; int eh_active; + wait_queue_head_t eh_wait_q; + struct list_head eh_dev_q; struct mutex disco_mutex; -- 2.7.4