[SCSI] libsas: fix sas_unregister_ports vs sas_drain_work
We need to hold drain_mutex across the unregistration as port down events
queue device removal as chained events, so we need to make sure no other
drainers are active.
[ 1118.673968] WARNING: at kernel/workqueue.c:996 __queue_work+0x11a/0x326()
[ 1118.681982] Hardware name: S2600CP
[ 1118.686193] Modules linked in: isci(-) libsas scsi_transport_sas nls_utf8
ipv6 uinput sg iTCO_wdt iTCO_vendor_support i2c_i801 i2c_core ioatdma dca
sd_mod sr_mod cdrom ahci libahci libata [last unloaded: scsi_transport_sas]
[ 1118.709893] Pid: 6831, comm: rmmod Not tainted 3.2.0-isci+ #1
[ 1118.716727] Call Trace:
[ 1118.719867] [<ffffffff8103e9f5>] warn_slowpath_common+0x85/0x9d
[ 1118.727000] [<ffffffff8103ea27>] warn_slowpath_null+0x1a/0x1c
[ 1118.733942] [<ffffffff81056d44>] __queue_work+0x11a/0x326
[ 1118.740481] [<ffffffff81056f99>] queue_work_on+0x1b/0x22
[ 1118.746925] [<ffffffff81057106>] queue_work+0x37/0x3e
[ 1118.753105] [<ffffffffa0120e05>] ? sas_discover_event+0x55/0x82 [libsas]
[ 1118.761094] [<ffffffff813217c3>] scsi_queue_work+0x42/0x44
[ 1118.767717] [<ffffffffa0120e19>] sas_discover_event+0x69/0x82 [libsas]
[ 1118.775509] [<ffffffffa0120f5b>] sas_unregister_dev+0xc3/0xcc [libsas]
[ 1118.783319] [<ffffffffa0120fae>] sas_unregister_domain_devices+0x4a/0xc8 [libsas]
[ 1118.792731] [<ffffffffa0120071>] sas_deform_port+0x60/0x1a6 [libsas]
[ 1118.800339] [<ffffffffa01201ea>] sas_unregister_ports+0x33/0x44 [libsas]
[ 1118.808342] [<ffffffffa011f7e5>] sas_unregister_ha+0x41/0x6b [libsas]
[ 1118.816055] [<ffffffffa0134055>] isci_unregister+0x22/0x4d [isci]
[ 1118.823384] [<ffffffffa0143040>] isci_pci_remove+0x2e/0x60 [isci]
Reported-by: Jacek Danecki <jacek.danecki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/libsas/sas_internal.h b/drivers/scsi/libsas/sas_internal.h
index 4157f6e..7818c46 100644
--- a/drivers/scsi/libsas/sas_internal.h
+++ b/drivers/scsi/libsas/sas_internal.h
@@ -70,6 +70,7 @@
void sas_shutdown_queue(struct sas_ha_struct *sas_ha);
void sas_disable_revalidation(struct sas_ha_struct *ha);
void sas_enable_revalidation(struct sas_ha_struct *ha);
+void __sas_drain_work(struct sas_ha_struct *ha);
void sas_deform_port(struct asd_sas_phy *phy, int gone);