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authorNicholas Bellinger <nab@linux-iscsi.org>2012-07-15 02:11:41 +0400
committerNicholas Bellinger <nab@linux-iscsi.org>2012-07-17 04:35:24 +0400
commit77d4c7450646e6bcba3ff6de17aa4b98c34fe849 (patch)
treefc4ae4f156b5265cdd1583cb01cbfbd405157967 /drivers/target
parente80ac6c4cc073d54daef8ba4ced88347d130d314 (diff)
downloadlinux-77d4c7450646e6bcba3ff6de17aa4b98c34fe849.tar.xz
target: Make core_disable_device_list_for_node use pre-refactoring lock ordering
So after kicking around commit 547ac4c9c90 around a bit more, a tcm_qla2xxx LUN unlink OP has generated the following warning: [ 50.386625] qla2xxx [0000:07:00.0]-00af:0: Performing ISP error recovery - ha=ffff880263774000. [ 70.572988] qla2xxx [0000:07:00.0]-8038:0: Cable is unplugged... [ 126.527531] ------------[ cut here ]------------ [ 126.532677] WARNING: at kernel/softirq.c:159 local_bh_enable_ip+0x41/0x8c() [ 126.540433] Hardware name: S5520HC [ 126.544248] Modules linked in: tcm_vhost ib_srpt ib_cm ib_sa ib_mad ib_core tcm_qla2xxx tcm_loop tcm_fc libfc iscsi_target_mod target_core_pscsi target_core_file target_core_iblock target_core_mod configfs ipv6 iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi dm_round_robin dm_multipath scsi_dh loop i2c_i801 kvm_intel kvm crc32c_intel i2c_core microcode joydev button iomemory_vsl(O) pcspkr ext3 jbd uhci_hcd lpfc ata_piix libata ehci_hcd qla2xxx mlx4_core scsi_transport_fc scsi_tgt igb [last unloaded: scsi_wait_scan] [ 126.595567] Pid: 3283, comm: unlink Tainted: G O 3.5.0-rc2+ #33 [ 126.603128] Call Trace: [ 126.605853] [<ffffffff81026b91>] ? warn_slowpath_common+0x78/0x8c [ 126.612737] [<ffffffff8102c342>] ? local_bh_enable_ip+0x41/0x8c [ 126.619433] [<ffffffffa03582a2>] ? core_disable_device_list_for_node+0x70/0xe3 [target_core_mod] [ 126.629323] [<ffffffffa035849f>] ? core_clear_lun_from_tpg+0x88/0xeb [target_core_mod] [ 126.638244] [<ffffffffa0362ec1>] ? core_tpg_post_dellun+0x17/0x48 [target_core_mod] [ 126.646873] [<ffffffffa03575ee>] ? core_dev_del_lun+0x26/0x8c [target_core_mod] [ 126.655114] [<ffffffff810bcbd1>] ? dput+0x27/0x154 [ 126.660549] [<ffffffffa0359aa0>] ? target_fabric_port_unlink+0x3b/0x41 [target_core_mod] [ 126.669661] [<ffffffffa034a698>] ? configfs_unlink+0xfc/0x14a [configfs] [ 126.677224] [<ffffffff810b5979>] ? vfs_unlink+0x58/0xb7 [ 126.683141] [<ffffffff810b6ef3>] ? do_unlinkat+0xbb/0x142 [ 126.689253] [<ffffffff81330c75>] ? page_fault+0x25/0x30 [ 126.695170] [<ffffffff81335df9>] ? system_call_fastpath+0x16/0x1b [ 126.702053] ---[ end trace 2f8e5b0a9ec797ef ]--- [ 126.756336] qla2xxx [0000:07:00.0]-00af:0: Performing ISP error recovery - ha=ffff880263774000. [ 146.942414] qla2xxx [0000:07:00.0]-8038:0: Cable is unplugged... So this warning triggered because device_list disable logic is now holding nacl->device_list_lock w/ spin_lock_irqsave before obtaining port->sep_alua_lock with only spin_lock_bh.. The original disable logic obtains *deve ahead of dropping the entry from deve->alua_port_list and then obtains ->device_list_lock to do the remaining work. Also, I'm pretty sure this particular warning is being generated by a demo-mode session in tcm_qla2xxx, and not by explicit NodeACL MappedLUNs. The Initiator MappedLUNs are already protected by a seperate configfs symlink reference back se_lun->lun_group, and the demo-mode se_node_acl (and associated ->device_list[]) is released during se_portal_group->tpg_group shutdown. The following patch drops the extra functional change to disable logic in commit 547ac4c9c90 Cc: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_device.c9
1 files changed, 2 insertions, 7 deletions
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 0a1c907a531b..0048d0a0b0c1 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -432,11 +432,7 @@ int core_disable_device_list_for_node(
struct se_portal_group *tpg)
{
struct se_port *port = lun->lun_sep;
- struct se_dev_entry *deve;
-
- spin_lock_irq(&nacl->device_list_lock);
-
- deve = nacl->device_list[mapped_lun];
+ struct se_dev_entry *deve = nacl->device_list[mapped_lun];
/*
* If the MappedLUN entry is being disabled, the entry in
@@ -454,14 +450,13 @@ int core_disable_device_list_for_node(
spin_lock_bh(&port->sep_alua_lock);
list_del(&deve->alua_port_list);
spin_unlock_bh(&port->sep_alua_lock);
-
/*
* Wait for any in process SPEC_I_PT=1 or REGISTER_AND_MOVE
* PR operation to complete.
*/
- spin_unlock_irq(&nacl->device_list_lock);
while (atomic_read(&deve->pr_ref_count) != 0)
cpu_relax();
+
spin_lock_irq(&nacl->device_list_lock);
/*
* Disable struct se_dev_entry LUN ACL mapping