From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexis Bruemmer Subject: [PATCH 2/4] aic94xx: fix to serialize unload and discovery Date: Thu, 09 Nov 2006 12:03:15 -0800 Message-ID: <1163102596.6521.17.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from e3.ny.us.ibm.com ([32.97.182.143]:31106 "EHLO e3.ny.us.ibm.com") by vger.kernel.org with ESMTP id S965418AbWKIUEx (ORCPT ); Thu, 9 Nov 2006 15:04:53 -0500 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e3.ny.us.ibm.com (8.13.8/8.12.11) with ESMTP id kA9K4mBJ025844 for ; Thu, 9 Nov 2006 15:04:49 -0500 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay04.pok.ibm.com (8.13.6/8.13.6/NCO v8.1.1) with ESMTP id kA9K4Isb231708 for ; Thu, 9 Nov 2006 15:04:21 -0500 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id kA9K3HYd023704 for ; Thu, 9 Nov 2006 15:03:18 -0500 Received: from [9.48.54.0] ([9.48.54.0]) by d01av03.pok.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id kA9K3Gl2023619 for ; Thu, 9 Nov 2006 15:03:17 -0500 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi sas_discover_domain() and sas_deform_port() assume that they are single threaded and never run in parallel. That is mostly true as we have a single threaded work queue to handle discovery and other events. The only race I find is unloading a module will call sas_deform_port() without watching if there is a discovery event is in progress. This patch will stop queuing further events, flush the queue, and then call sas_deform_port() to avoid the race. Signed-off-by: Malahal Naineni --- diff -r 8fe3b862f968 drivers/scsi/libsas/sas_discover.c --- a/drivers/scsi/libsas/sas_discover.c Tue Oct 17 13:24:04 2006 -0700 +++ b/drivers/scsi/libsas/sas_discover.c Tue Oct 17 13:25:28 2006 -0700 @@ -722,7 +722,7 @@ int sas_discover_event(struct asd_sas_po BUG_ON(ev >= DISC_NUM_EVENTS); sas_queue_event(ev, &disc->disc_event_lock, &disc->pending, - &disc->disc_work[ev], port->ha->core.shost); + &disc->disc_work[ev], port->ha); return 0; } diff -r 8fe3b862f968 drivers/scsi/libsas/sas_event.c --- a/drivers/scsi/libsas/sas_event.c Tue Oct 17 13:24:04 2006 -0700 +++ b/drivers/scsi/libsas/sas_event.c Tue Oct 17 13:25:28 2006 -0700 @@ -31,7 +31,7 @@ static void notify_ha_event(struct sas_h BUG_ON(event >= HA_NUM_EVENTS); sas_queue_event(event, &sas_ha->event_lock, &sas_ha->pending, - &sas_ha->ha_events[event], sas_ha->core.shost); + &sas_ha->ha_events[event], sas_ha); } static void notify_port_event(struct asd_sas_phy *phy, enum port_event event) @@ -41,7 +41,7 @@ static void notify_port_event(struct asd BUG_ON(event >= PORT_NUM_EVENTS); sas_queue_event(event, &ha->event_lock, &phy->port_events_pending, - &phy->port_events[event], ha->core.shost); + &phy->port_events[event], ha); } static void notify_phy_event(struct asd_sas_phy *phy, enum phy_event event) @@ -51,7 +51,7 @@ static void notify_phy_event(struct asd_ BUG_ON(event >= PHY_NUM_EVENTS); sas_queue_event(event, &ha->event_lock, &phy->phy_events_pending, - &phy->phy_events[event], ha->core.shost); + &phy->phy_events[event], ha); } int sas_init_events(struct sas_ha_struct *sas_ha) diff -r 8fe3b862f968 drivers/scsi/libsas/sas_init.c --- a/drivers/scsi/libsas/sas_init.c Tue Oct 17 13:24:04 2006 -0700 +++ b/drivers/scsi/libsas/sas_init.c Tue Oct 17 13:29:02 2006 -0700 @@ -85,6 +85,9 @@ int sas_register_ha(struct sas_ha_struct else if (sas_ha->lldd_queue_size == -1) sas_ha->lldd_queue_size = 128; /* Sanity */ + sas_ha->state = SAS_HA_REGISTERED; + spin_lock_init(&sas_ha->state_lock); + error = sas_register_phys(sas_ha); if (error) { printk(KERN_NOTICE "couldn't register sas phys:%d\n", error); @@ -123,9 +126,18 @@ Undo_phys: int sas_unregister_ha(struct sas_ha_struct *sas_ha) { + unsigned long flags; + if (sas_ha->lldd_max_execute_num > 1) { sas_shutdown_queue(sas_ha); } + + /* Set the state to unregistered to avoid further + * events to be queued */ + spin_lock_irqsave(&sas_ha->state_lock, flags); + sas_ha->state = SAS_HA_UNREGISTERED; + spin_unlock_irqrestore(&sas_ha->state_lock, flags); + scsi_flush_work(sas_ha->core.shost); sas_unregister_ports(sas_ha); diff -r 8fe3b862f968 drivers/scsi/libsas/sas_internal.h --- a/drivers/scsi/libsas/sas_internal.h Tue Oct 17 13:24:04 2006 -0700 +++ b/drivers/scsi/libsas/sas_internal.h Tue Oct 17 13:25:28 2006 -0700 @@ -80,7 +80,7 @@ static inline void sas_queue_event(int e static inline void sas_queue_event(int event, spinlock_t *lock, unsigned long *pending, struct work_struct *work, - struct Scsi_Host *shost) + struct sas_ha_struct *sas_ha) { unsigned long flags; @@ -91,7 +91,12 @@ static inline void sas_queue_event(int e } __set_bit(event, pending); spin_unlock_irqrestore(lock, flags); - scsi_queue_work(shost, work); + + spin_lock_irqsave(&sas_ha->state_lock, flags); + if (sas_ha->state != SAS_HA_UNREGISTERED) { + scsi_queue_work(sas_ha->core.shost, work); + } + spin_unlock_irqrestore(&sas_ha->state_lock, flags); } static inline void sas_begin_event(int event, spinlock_t *lock, diff -r 8fe3b862f968 include/scsi/libsas.h --- a/include/scsi/libsas.h Tue Oct 17 13:24:04 2006 -0700 +++ b/include/scsi/libsas.h Tue Oct 17 13:25:28 2006 -0700 @@ -307,11 +307,19 @@ struct scsi_core { int queue_thread_kill; }; +enum sas_ha_state { + SAS_HA_REGISTERED, + SAS_HA_UNREGISTERED +}; + struct sas_ha_struct { /* private: */ spinlock_t event_lock; struct work_struct ha_events[HA_NUM_EVENTS]; unsigned long pending; + + enum sas_ha_state state; + spinlock_t state_lock; struct scsi_core core;