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authorChristof Schmitt <christof.schmitt@de.ibm.com>2009-09-24 10:23:25 +0200
committerJames Bottomley <James.Bottomley@suse.de>2009-10-02 09:50:21 -0500
commitd74cf7c3e9c4a6a659e0442aafb550b162d15e72 (patch)
tree2608dca9dd748a1234ea0e44679e9902b1d3b35b
parentf45a54214a0770582af06bb1e807493d1b7268ab (diff)
[SCSI] zfcp: Fix hang when offlining device with offline chpid
Running chchp --vary 0 and chccwdev -d on a FCP device with scsi devices attached can lead to this thread hanging: ================================================================ STACK TRACE FOR TASK: 0x2fbfcc00 (kslowcrw) STACK: 0 schedule+1136 [0x45f99c] 1 schedule_timeout+534 [0x46054e] 2 wait_for_common+374 [0x45f442] 3 blk_execute_rq+160 [0x217a2c] 4 scsi_execute+278 [0x26daf2] 5 scsi_execute_req+150 [0x26dc86] 6 sd_sync_cache+138 [0x28460a] 7 sd_shutdown+130 [0x28486a] 8 sd_remove+104 [0x284c84] 9 __device_release_driver+152 [0x257430] 10 device_release_driver+56 [0x2575c8] 11 bus_remove_device+214 [0x25672a] 12 device_del+352 [0x25456c] 13 __scsi_remove_device+108 [0x272630] 14 scsi_remove_device+66 [0x2726ba] 15 zfcp_ccw_remove+824 [0x335558] 16 ccw_device_remove+62 [0x2b3f2a] 17 __device_release_driver+152 [0x257430] 18 device_release_driver+56 [0x2575c8] 19 bus_remove_device+214 [0x25672a] 20 device_del+352 [0x25456c] 21 ccw_device_unregister+92 [0x2b48c4] 22 io_subchannel_remove+108 [0x2b4950] 23 css_remove+62 [0x2af7ee] 24 __device_release_driver+152 [0x257430] 25 device_release_driver+56 [0x2575c8] 26 bus_remove_device+214 [0x25672a] 27 device_del+352 [0x25456c] 28 device_unregister+38 [0x25464a] 29 css_sch_device_unregister+68 [0x2af97c] 30 ccw_device_call_sch_unregister+78 [0x2b581e] 31 worker_thread+604 [0x69eb0] 32 kthread+154 [0x6ff42] 33 kernel_thread_starter+6 [0x1c952] ================================================================ The problem is that the chchp --vary 0 leads to zfcp first calling fc_remote_port_delete which blocks all scsi devices on the remote port. Calling scsi_remove_device later lets the sd driver issue a SYNCHRONIZE_CACHE command. This command stays on the "stopped" request requeue because the SCSI device is blocked. Fix this by first removing the scsi and fc hosts which removes all scsi devices and do not use scsi_remove_device. Reviewed-by: Felix Beck <felix.beck@de.ibm.com> Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
-rw-r--r--drivers/s390/scsi/zfcp_aux.c1
-rw-r--r--drivers/s390/scsi/zfcp_ccw.c9
2 files changed, 5 insertions, 5 deletions
diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 5dcac24a7a1..0f79f3af4f5 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -604,7 +604,6 @@ void zfcp_adapter_dequeue(struct zfcp_adapter *adapter)
cancel_work_sync(&adapter->stat_work);
zfcp_fc_wka_ports_force_offline(adapter->gs);
- zfcp_adapter_scsi_unregister(adapter);
sysfs_remove_group(&adapter->ccw_device->dev.kobj,
&zfcp_sysfs_adapter_attrs);
dev_set_drvdata(&adapter->ccw_device->dev, NULL);
diff --git a/drivers/s390/scsi/zfcp_ccw.c b/drivers/s390/scsi/zfcp_ccw.c
index 9fe32f7ec8d..e08339428ec 100644
--- a/drivers/s390/scsi/zfcp_ccw.c
+++ b/drivers/s390/scsi/zfcp_ccw.c
@@ -107,6 +107,10 @@ static void zfcp_ccw_remove(struct ccw_device *ccw_device)
cancel_work_sync(&adapter->scan_work);
mutex_lock(&zfcp_data.config_mutex);
+
+ /* this also removes the scsi devices, so call it first */
+ zfcp_adapter_scsi_unregister(adapter);
+
write_lock_irq(&zfcp_data.config_lock);
list_for_each_entry_safe(port, p, &adapter->port_list_head, list) {
list_for_each_entry_safe(unit, u, &port->unit_list_head, list) {
@@ -121,11 +125,8 @@ static void zfcp_ccw_remove(struct ccw_device *ccw_device)
write_unlock_irq(&zfcp_data.config_lock);
list_for_each_entry_safe(port, p, &port_remove_lh, list) {
- list_for_each_entry_safe(unit, u, &unit_remove_lh, list) {
- if (unit->device)
- scsi_remove_device(unit->device);
+ list_for_each_entry_safe(unit, u, &unit_remove_lh, list)
zfcp_unit_dequeue(unit);
- }
zfcp_port_dequeue(port);
}
wait_event(adapter->remove_wq, atomic_read(&adapter->refcount) == 0);