[PATCH 1/1] enclosure: fix WARN_ON in dual path device removing

[wenxiong@linux.vnet.ibm.com]

[-- Attachment #1: rmmd_fix --]
[-- Type: text/plain, Size: 4613 bytes --]

The issue is happened in dual controller configuration. We got the
sysfs warnings when rmmod the ipr module.

enclosure_unregister() in drivers/msic/enclosure.c, call device_unregister()
for each componment deivce, device_unregister() ->device_del()->kobject_del()
->sysfs_remove_dir(). In sysfs_remove_dir(), set kobj->sd = NULL.

For each componment device, enclosure_component_release()->enclosure_remove_links()->sysfs_remove_link() in which checking kobj->sd again, it has been set as NULL when doing device_unregister. So we saw all these sysfs WARNING.

sysfs: can not remove 'enclosure_device: P1-D1      2SS6', no directory
------------[ cut here ]------------
WARNING: at fs/sysfs/inode.c:325
Modules linked in: fuse loop dm_mod ses enclosure ipr(-) ipv6 ibmveth libata sg ext3 jbd mbcache sd_mod crc_t10dif crct10dif_common ibmvscsi scsi_transport_srp scsi_tgt scsi_dh_rdac scsi_dh_emc scsi_dh_hp_sw scsi_dh_alua scsi_dh scsi_mod
CPU: 0 PID: 4006 Comm: rmmod Not tainted 3.12.0-scsi-0.11-ppc64 #1
task: c0000000f769aba0 ti: c0000000f8f9c000 task.ti: c0000000f8f9c000
NIP: c0000000002b038c LR: c0000000002b0388 CTR: 0000000000000000
REGS: c0000000f8f9ee70 TRAP: 0700   Not tainted  (3.12.0-scsi-0.11-ppc64)
MSR: 8000000000029032 <SF,EE,ME,IR,DR,RI>  CR: 28008444  XER: 20000000
SOFTE: 1
CFAR: c000000000736118

GPR00: c0000000002b0388 c0000000f8f9f0f0 c0000000010ed630 0000000000000047 
GPR04: c000000001502628 c000000001513010 0000000000000689 652027656e636c6f 
GPR08: 737572655f646576 c000000000ae2b7c 0000000000a20000 c000000000add630 
GPR12: 0000000028008442 c000000007f20000 0000000000000000 0000000010146920 
GPR16: 00000000100cb9d8 0000000010093088 0000000010146920 0000000000000000 
GPR20: 0000000000000000 0000000010161900 00000000100ce458 0000000000000000 
GPR24: 0000000010161940 0000000000000000 d0000000046ad440 0000000000000000 
GPR28: c0000000f8f9f270 0000000000000000 c0000000fcb882c8 0000000000000000 
NIP [c0000000002b038c] .sysfs_hash_and_remove+0xe4/0xf0
LR [c0000000002b0388] .sysfs_hash_and_remove+0xe0/0xf0
Call Trace:
[c0000000f8f9f0f0] [c0000000002b0388] .sysfs_hash_and_remove+0xe0/0xf0 (unreliable)
[c0000000f8f9f190] [c0000000002b4134] .sysfs_remove_link+0x24/0x60
[c0000000f8f9f200] [d000000004df037c] .enclosure_remove_links+0x64/0xa0 [enclosure]
[c0000000f8f9f2d0] [d000000004df0518] .enclosure_component_release+0x30/0x60 [enclosure]
[c0000000f8f9f350] [c000000000540068] .device_release+0x50/0xd8
[c0000000f8f9f3d0] [c0000000003b6f80] .kobject_cleanup+0xb8/0x230
[c0000000f8f9f460] [c00000000053f404] .put_device+0x1c/0x30
[c0000000f8f9f4d0] [d000000004df0db0] .enclosure_unregister+0xa0/0xe8 [enclosure]
[c0000000f8f9f560] [d000000004f90094] .ses_intf_remove_enclosure+0x8c/0xa8 [ses]
[c0000000f8f9f5f0] [c0000000005413ec] .device_del+0xf4/0x268
[c0000000f8f9f680] [c000000000541594] .device_unregister+0x34/0x88
[c0000000f8f9f700] [d000000001423d3c] .__scsi_remove_device+0x104/0x128 [scsi_mod]
[c0000000f8f9f780] [d00000000141eff8] .scsi_forget_host+0x70/0xa0 [scsi_mod]
[c0000000f8f9f800] [d000000001413dc0] .scsi_remove_host+0x88/0x178 [scsi_mod]
[c0000000f8f9f890] [d00000000469db5c] .ipr_remove+0x7c/0xf8 [ipr]
[c0000000f8f9f920] [c0000000003fe1f4] .pci_device_remove+0x64/0xf0
[c0000000f8f9f9b0] [c000000000544f10] .__device_release_driver+0xd0/0x158
[c0000000f8f9fa40] [c0000000005450d8] .driver_detach+0x140/0x148
[c0000000f8f9fae0] [c000000000543848] .bus_remove_driver+0xe0/0x188
[c0000000f8f9fb70] [c00000000054628c] .driver_unregister+0x3c/0x80
[c0000000f8f9fbf0] [c0000000003fe35c] .pci_unregister_driver+0x34/0xe8
[c0000000f8f9fc90] [d0000000046a5fb4] .ipr_exit+0x2c/0x44 [ipr]
[c0000000f8f9fd20] [c0000000001359dc] .SyS_delete_module+0x204/0x308
[c0000000f8f9fe30] [c000000000009f60] syscall_exit+0x0/0xa0
Instruction dump:
e8010010 eb81ffe0 7c0803a6 eba1ffe8 ebc1fff0 ebe1fff8 4e800020 3c62ff8a 
7ca42b78 3863c388 48485d45 60000000 <0fe00000> 3860fffe 4bffff94 fba1ffe8 
o
Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
---
 drivers/misc/enclosure.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: b/drivers/misc/enclosure.c
===================================================================
--- a/drivers/misc/enclosure.c	2013-11-08 12:30:25.000000000 -0600
+++ b/drivers/misc/enclosure.c	2013-11-08 14:47:55.527765695 -0600
@@ -233,7 +233,8 @@ static void enclosure_component_release(
 	struct enclosure_component *cdev = to_enclosure_component(dev);
 
 	if (cdev->dev) {
-		enclosure_remove_links(cdev);
+		if (dev->kobj.sd)
+			enclosure_remove_links(cdev);
 		put_device(cdev->dev);
 	}
 	put_device(dev->parent);

--