[PATCH 2/2] scsi: isci: remove the SAS host after the SCSI host

[Johannes Thumshirn]

After commit bcdde7e ("sysfs: make __sysfs_remove_dir() recursive") changed the
removal path of kernfs to make it recursive we have to remove the SAS host
before the SCSI host or we will see sysfs warnings like the below when
triggering the the removal of the SAS HBA PCI device like with writing to the
sysfs pci remove file:

echo 1 > /sys/module/isci/drivers/pci:isci/<device>/remove

WARNING: CPU: 2 PID: 5 at fs/sysfs/group.c:241 sysfs_remove_group+0xc3/0xd0
sysfs group 'power' not found for kobject 'end_device-6:0'
CPU: 16 PID: 5884 Comm: echo Not tainted 4.11.0-rc3-libsas+ #504
Call Trace:
 dump_stack+0x85/0xc2
 __warn+0xc6/0xe0
 warn_slowpath_fmt+0x4a/0x50
 sysfs_remove_group+0xc3/0xd0
 dpm_sysfs_remove+0x52/0x60
 device_del+0x13c/0x360
 ? device_remove_file+0x14/0x20
 attribute_container_class_device_del+0x15/0x20
 transport_remove_classdev+0x4c/0x60
 ? transport_add_class_device+0x40/0x40
 attribute_container_device_trigger+0xb3/0xc0
 transport_remove_device+0x10/0x20
 sas_port_delete+0x12d/0x160 [scsi_transport_sas]
 sas_deform_port+0x1bf/0x1d0 [libsas]
 sas_unregister_ports+0x36/0x50 [libsas]
 sas_unregister_ha+0x1b/0x40 [libsas]
 isci_unregister+0x2a/0x40 [isci]
 isci_pci_remove+0x52/0xb0 [isci]
 ? __pm_runtime_resume+0x56/0x80
 pci_device_remove+0x34/0xb0
 device_release_driver_internal+0x158/0x210
 device_release_driver+0xd/0x10
 pci_stop_bus_device+0x85/0x90
 pci_stop_and_remove_bus_device_locked+0x15/0x30
 remove_store+0x59/0x70
 dev_attr_store+0x13/0x20
 sysfs_kf_write+0x40/0x50
 kernfs_fop_write+0x130/0x1b0
 __vfs_write+0x23/0x130
 ? rcu_read_lock_sched_held+0x6d/0x80
 ? rcu_sync_lockdep_assert+0x2a/0x50
 ? __sb_start_write+0xd7/0x1e0
 ? vfs_write+0x1a4/0x1f0
 vfs_write+0xc6/0x1f0
 SyS_write+0x44/0xa0
 entry_SYSCALL_64_fastpath+0x23/0xc6

Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
---
 drivers/scsi/isci/init.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/isci/init.c b/drivers/scsi/isci/init.c
index 0b5b5db..afa6b25 100644
--- a/drivers/scsi/isci/init.c
+++ b/drivers/scsi/isci/init.c
@@ -267,15 +267,22 @@ static int isci_register_sas_ha(struct isci_host *isci_host)
 static void isci_unregister(struct isci_host *isci_host)
 {
 	struct Scsi_Host *shost;
+	unsigned long flags;
 
 	if (!isci_host)
 		return;
 
 	shost = to_shost(isci_host);
-	scsi_remove_host(shost);
+
+	spin_lock_irqsave(shost->host_lock, flags);
+	if (scsi_host_set_state(shost, SHOST_CANCEL))
+		WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
+	spin_unlock_irqrestore(shost->host_lock, flags);
+
 	sas_unregister_ha(&isci_host->sas_ha);
 
 	sas_remove_host(shost);
+	scsi_remove_host(shost);
 	scsi_host_put(shost);
 }
 
-- 
1.8.5.6