[PATCH 3.14 16/78] SCSI: scsi_transport_sas: move bsg destructor into sas_rphy_remove

Greg Kroah-Hartman
2014-06-09T23:13:05Z

From: Joe Lawrence <joe.lawrence@stratus.com>

commit 6aa6caff30f5dcb9e55b03b9710c30b83750cae5 upstream.

The recent change in sysfs, bcdde7e221a8750f9b62b6d0bd31b72ea4ad9309
"sysfs: make __sysfs_remove_dir() recursive" revealed an asymmetric
rphy device creation/deletion sequence in scsi_transport_sas:

modprobe mpt2sas
sas_rphy_add
device_add A rphy->dev
device_add B sas_device transport class
device_add C sas_end_device transport class
device_add D bsg class

rmmod mpt2sas
sas_rphy_delete
sas_rphy_remove
device_del B
device_del C
device_del A
sysfs_remove_group recursive sysfs dir removal
sas_rphy_free
device_del D warning

where device A is the parent of B, C, and D.

When sas_rphy_free tries to unregister the bsg request queue (device D
above), the ensuing sysfs cleanup discovers that its sysfs group has
already been removed and emits a warning, "sysfs group... not found for
kobject 'end_device-X:0'".

Since bsg creation is a side effect of sas_rphy_add, move its
complementary removal call into sas_rphy_remove. This imposes the
following tear-down order for the devices above: D, B, C, A.

Note the sas_device and sas_end_device transport class devices (B and C
above) are created and destroyed both via the list match traversal in
attribute_container_device_trigger, so the order in which they are
handled is fixed. This is fine as long as they are deleted before their
parent device.

Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/scsi_transport_sas.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -1621,8 +1621,6 @@ void sas_rphy_free(struct sas_rphy *rphy
list_del(&rphy->list);
mutex_unlock(&sas_host->lock);

- sas_bsg_remove(shost, rphy);
-
transport_destroy_device(dev);

put_device(dev);
@@ -1681,6 +1679,7 @@ sas_rphy_remove(struct sas_rphy *rphy)
}

sas_rphy_unlink(rphy);
+ sas_bsg_remove(NULL, rphy);
transport_remove_device(dev);
device_del(dev);
}