From 45316a86a67934ab499dcfac44c91aa8f39c4c78 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 4 Nov 2008 16:35:06 +0100 Subject: [PATCH] [SCSI] zfcp: fix req_list_locking. The per adapter req_list_lock must be held with interrupts disabled, otherwise we might end up with nice deadlocks as lockdep tells us (see below). zfcp 0.0.1804: QDIO problem occurred. ========================================================= [ INFO: possible irq lock inversion dependency detected ] 2.6.27-rc8-00035-g4a77035-dirty #86 --------------------------------------------------------- swapper/0 just changed the state of lock: (&adapter->erp_lock){++..}, at: [<00000000002c82ae>] zfcp_erp_adapter_reopen+0x4e/0x8c but this lock took another, hard-irq-unsafe lock in the past: (&adapter->req_list_lock){-+..} and interrupts could create inverse lock ordering between them. [tons of backtraces, but only the interesting part follows] the second lock's dependencies: -> (&adapter->req_list_lock){-+..} ops: 2280627634176 { initial-use at: [<0000000000071f10>] __lock_acquire+0x504/0x18bc [<000000000007335c>] lock_acquire+0x94/0xbc [<00000000003d7224>] _spin_lock_irqsave+0x6c/0xb0 [<00000000002cf684>] zfcp_fsf_req_dismiss_all+0x50/0x140 [<00000000002c87ee>] zfcp_erp_adapter_strategy_generic+0x66/0x3d0 [<00000000002c9498>] zfcp_erp_thread+0x88c/0x1318 [<000000000001b0d2>] kernel_thread_starter+0x6/0xc [<000000000001b0cc>] kernel_thread_starter+0x0/0xc in-softirq-W at: [<0000000000072172>] __lock_acquire+0x766/0x18bc [<000000000007335c>] lock_acquire+0x94/0xbc [<00000000003d7224>] _spin_lock_irqsave+0x6c/0xb0 [<00000000002ca73e>] zfcp_qdio_int_resp+0xbe/0x2ac [<000000000027a1d6>] qdio_kick_inbound_handler+0x82/0xa0 [<000000000027daba>] tiqdio_inbound_processing+0x62/0xf8 [<0000000000047ba4>] tasklet_action+0x100/0x1f4 [<0000000000048b5a>] __do_softirq+0xae/0x154 [<0000000000021e4a>] do_softirq+0xea/0xf0 [<00000000000485de>] irq_exit+0xde/0xe8 [<0000000000268c64>] do_IRQ+0x160/0x1fc [<00000000000261a2>] io_return+0x0/0x8 [<000000000001b8f8>] cpu_idle+0x17c/0x224 hardirq-on-W at: [<0000000000072190>] __lock_acquire+0x784/0x18bc [<000000000007335c>] lock_acquire+0x94/0xbc [<00000000003d702c>] _spin_lock+0x5c/0x9c [<00000000002caff6>] zfcp_fsf_req_send+0x3e/0x158 [<00000000002ce7fe>] zfcp_fsf_exchange_config_data+0x106/0x124 [<00000000002c8948>] zfcp_erp_adapter_strategy_generic+0x1c0/0x3d0 [<00000000002c98ea>] zfcp_erp_thread+0xcde/0x1318 [<000000000001b0d2>] kernel_thread_starter+0x6/0xc [<000000000001b0cc>] kernel_thread_starter+0x0/0xc } ... key at: [<0000000000e356c8>] __key.26629+0x0/0x8 Signed-off-by: Heiko Carstens Signed-off-by: Christof Schmitt Signed-off-by: James Bottomley --- drivers/s390/scsi/zfcp_fsf.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c index 5ae1d497e5ed..694d9c9ea7cc 100644 --- a/drivers/s390/scsi/zfcp_fsf.c +++ b/drivers/s390/scsi/zfcp_fsf.c @@ -770,13 +770,14 @@ static int zfcp_fsf_req_send(struct zfcp_fsf_req *req) { struct zfcp_adapter *adapter = req->adapter; struct zfcp_qdio_queue *req_q = &adapter->req_q; + unsigned long flags; int idx; /* put allocated FSF request into hash table */ - spin_lock(&adapter->req_list_lock); + spin_lock_irqsave(&adapter->req_list_lock, flags); idx = zfcp_reqlist_hash(req->req_id); list_add_tail(&req->list, &adapter->req_list[idx]); - spin_unlock(&adapter->req_list_lock); + spin_unlock_irqrestore(&adapter->req_list_lock, flags); req->qdio_outb_usage = atomic_read(&req_q->count); req->issued = get_clock(); -- 2.39.5