[PATCH 5/5] nvmet: fcloop: use irqsave spinlocks

Johannes Thumshirn jthumshirn at suse.de
Tue May 15 00:40:43 PDT 2018


Lockdep complains about inconsistent hardirq states when using
nvme-fcloop. So use the irqsave variant of spin_locks for the
nvmefc_fcp_req's reqlock.

Here's the lockdep report:
[   11.138417] ================================
[   11.139085] WARNING: inconsistent lock state
[   11.139207] nvmet: creating controller 2 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:046394e7-bff7-4403-9502-1816800efaa0.
[   11.139727] 4.17.0-rc5+ #883 Not tainted
[   11.139732] --------------------------------
[   11.144441] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
[   11.145341] swapper/8/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
[   11.146108]         (ptrval) (&(&tfcp_req->reqlock)->rlock){?.+.}, at: fcloop_fcp_op+0x20/0x1d0 [nvme_fcloop]
[   11.148633] {HARDIRQ-ON-W} state was registered at:
[   11.149380]   _raw_spin_lock+0x34/0x70
[   11.149940]   fcloop_fcp_recv_work+0x17/0x90 [nvme_fcloop]
[   11.150746]   process_one_work+0x1d8/0x5c0
[   11.151346]   worker_thread+0x45/0x3e0
[   11.151886]   kthread+0x101/0x140
[   11.152370]   ret_from_fork+0x3a/0x50
[   11.152903] irq event stamp: 36666
[   11.153402] hardirqs last  enabled at (36663): [<ffffffffafc601c3>] default_idle+0x13/0x180
[   11.154601] hardirqs last disabled at (36664): [<ffffffffafe00964>] interrupt_entry+0xc4/0xe0
[   11.155817] softirqs last  enabled at (36666): [<ffffffffaf267409>] irq_enter+0x59/0x60
[   11.156952] softirqs last disabled at (36665): [<ffffffffaf2673ee>] irq_enter+0x3e/0x60
[   11.158092]
[   11.158092] other info that might help us debug this:
[   11.159436]  Possible unsafe locking scenario:
[   11.159436]
[   11.160299]        CPU0
[   11.160663]        ----
[   11.161026]   lock(&(&tfcp_req->reqlock)->rlock);
[   11.161709]   <Interrupt>
[   11.162091]     lock(&(&tfcp_req->reqlock)->rlock);
[   11.163148]
[   11.163148]  *** DEADLOCK ***
[   11.163148]
[   11.164007] no locks held by swapper/8/0.
[   11.164596]
[   11.164596] stack backtrace:
[   11.165238] CPU: 8 PID: 0 Comm: swapper/8 Not tainted 4.17.0-rc5+ #883
[   11.166180] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
[   11.167673] Call Trace:
[   11.168037]  <IRQ>
[   11.168349]  dump_stack+0x78/0xb3
[   11.168864]  print_usage_bug+0x1ed/0x1fe
[   11.169440]  ? check_usage_backwards+0x110/0x110
[   11.170111]  mark_lock+0x263/0x2a0
[   11.170995]  __lock_acquire+0x675/0x1870
[   11.171865]  ? __lock_acquire+0x48d/0x1870
[   11.172460]  lock_acquire+0xd4/0x220
[   11.172981]  ? fcloop_fcp_op+0x20/0x1d0 [nvme_fcloop]
[   11.173709]  _raw_spin_lock+0x34/0x70
[   11.174243]  ? fcloop_fcp_op+0x20/0x1d0 [nvme_fcloop]
[   11.174978]  fcloop_fcp_op+0x20/0x1d0 [nvme_fcloop]
[   11.175673]  nvmet_fc_transfer_fcp_data+0x9b/0x130 [nvmet_fc]
[   11.176507]  nvmet_req_complete+0x10/0x110 [nvmet]
[   11.177210]  nvmet_bio_done+0x23/0x40 [nvmet]
[   11.177837]  blk_update_request+0xab/0x3b0
[   11.178434]  blk_mq_end_request+0x13/0x60
[   11.179033]  flush_smp_call_function_queue+0x58/0x150
[   11.179755]  smp_call_function_single_interrupt+0x49/0x260
[   11.180531]  call_function_single_interrupt+0xf/0x20
[   11.181236]  </IRQ>
[   11.181542] RIP: 0010:native_safe_halt+0x2/0x10
[   11.182186] RSP: 0018:ffffa481006cbec0 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff04
[   11.183265] RAX: ffff9f54f8b86200 RBX: ffff9f54f8b86200 RCX: 0000000000000000
[   11.184264] RDX: ffff9f54f8b86200 RSI: 0000000000000001 RDI: ffff9f54f8b86200
[   11.185270] RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
[   11.186271] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
[   11.187280] R13: 0000000000000000 R14: ffff9f54f8b86200 R15: ffff9f54f8b86200
[   11.188280]  default_idle+0x18/0x180
[   11.188806]  do_idle+0x176/0x260
[   11.189273]  cpu_startup_entry+0x5a/0x60
[   11.189832]  start_secondary+0x18f/0x1b0

Signed-off-by: Johannes Thumshirn <jthumshirn at suse.de>
Cc: James Smart <james.smart at broadcom.com>
---
 drivers/nvme/target/fcloop.c | 52 ++++++++++++++++++++++++--------------------
 1 file changed, 29 insertions(+), 23 deletions(-)

diff --git a/drivers/nvme/target/fcloop.c b/drivers/nvme/target/fcloop.c
index d2209c60f95f..f4a3700201c1 100644
--- a/drivers/nvme/target/fcloop.c
+++ b/drivers/nvme/target/fcloop.c
@@ -406,9 +406,10 @@ fcloop_fcp_recv_work(struct work_struct *work)
 		container_of(work, struct fcloop_fcpreq, fcp_rcv_work);
 	struct nvmefc_fcp_req *fcpreq = tfcp_req->fcpreq;
 	int ret = 0;
+	unsigned long flags;
 	bool aborted = false;
 
-	spin_lock(&tfcp_req->reqlock);
+	spin_lock_irqsave(&tfcp_req->reqlock, flags);
 	switch (tfcp_req->inistate) {
 	case INI_IO_START:
 		tfcp_req->inistate = INI_IO_ACTIVE;
@@ -417,11 +418,11 @@ fcloop_fcp_recv_work(struct work_struct *work)
 		aborted = true;
 		break;
 	default:
-		spin_unlock(&tfcp_req->reqlock);
+		spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 		WARN_ON(1);
 		return;
 	}
-	spin_unlock(&tfcp_req->reqlock);
+	spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 
 	if (unlikely(aborted))
 		ret = -ECANCELED;
@@ -442,8 +443,9 @@ fcloop_fcp_abort_recv_work(struct work_struct *work)
 		container_of(work, struct fcloop_fcpreq, abort_rcv_work);
 	struct nvmefc_fcp_req *fcpreq;
 	bool completed = false;
+	unsigned long flags;
 
-	spin_lock(&tfcp_req->reqlock);
+	spin_lock_irqsave(&tfcp_req->reqlock, flags);
 	fcpreq = tfcp_req->fcpreq;
 	switch (tfcp_req->inistate) {
 	case INI_IO_ABORTED:
@@ -452,11 +454,11 @@ fcloop_fcp_abort_recv_work(struct work_struct *work)
 		completed = true;
 		break;
 	default:
-		spin_unlock(&tfcp_req->reqlock);
+		spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 		WARN_ON(1);
 		return;
 	}
-	spin_unlock(&tfcp_req->reqlock);
+	spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 
 	if (unlikely(completed)) {
 		/* remove reference taken in original abort downcall */
@@ -468,9 +470,9 @@ fcloop_fcp_abort_recv_work(struct work_struct *work)
 		nvmet_fc_rcv_fcp_abort(tfcp_req->tport->targetport,
 					&tfcp_req->tgt_fcp_req);
 
-	spin_lock(&tfcp_req->reqlock);
+	spin_lock_irqsave(&tfcp_req->reqlock, flags);
 	tfcp_req->fcpreq = NULL;
-	spin_unlock(&tfcp_req->reqlock);
+	spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 
 	fcloop_call_host_done(fcpreq, tfcp_req, -ECANCELED);
 	/* call_host_done releases reference for abort downcall */
@@ -486,11 +488,12 @@ fcloop_tgt_fcprqst_done_work(struct work_struct *work)
 	struct fcloop_fcpreq *tfcp_req =
 		container_of(work, struct fcloop_fcpreq, tio_done_work);
 	struct nvmefc_fcp_req *fcpreq;
+	unsigned long flags;
 
-	spin_lock(&tfcp_req->reqlock);
+	spin_lock_irqsave(&tfcp_req->reqlock, flags);
 	fcpreq = tfcp_req->fcpreq;
 	tfcp_req->inistate = INI_IO_COMPLETED;
-	spin_unlock(&tfcp_req->reqlock);
+	spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 
 	fcloop_call_host_done(fcpreq, tfcp_req, tfcp_req->status);
 }
@@ -594,13 +597,14 @@ fcloop_fcp_op(struct nvmet_fc_target_port *tgtport,
 	u32 rsplen = 0, xfrlen = 0;
 	int fcp_err = 0, active, aborted;
 	u8 op = tgt_fcpreq->op;
+	unsigned long flags;
 
-	spin_lock(&tfcp_req->reqlock);
+	spin_lock_irqsave(&tfcp_req->reqlock, flags);
 	fcpreq = tfcp_req->fcpreq;
 	active = tfcp_req->active;
 	aborted = tfcp_req->aborted;
 	tfcp_req->active = true;
-	spin_unlock(&tfcp_req->reqlock);
+	spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 
 	if (unlikely(active))
 		/* illegal - call while i/o active */
@@ -608,9 +612,9 @@ fcloop_fcp_op(struct nvmet_fc_target_port *tgtport,
 
 	if (unlikely(aborted)) {
 		/* target transport has aborted i/o prior */
-		spin_lock(&tfcp_req->reqlock);
+		spin_lock_irqsave(&tfcp_req->reqlock, flags);
 		tfcp_req->active = false;
-		spin_unlock(&tfcp_req->reqlock);
+		spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 		tgt_fcpreq->transferred_length = 0;
 		tgt_fcpreq->fcp_error = -ECANCELED;
 		tgt_fcpreq->done(tgt_fcpreq);
@@ -666,9 +670,9 @@ fcloop_fcp_op(struct nvmet_fc_target_port *tgtport,
 		break;
 	}
 
-	spin_lock(&tfcp_req->reqlock);
+	spin_lock_irqsave(&tfcp_req->reqlock, flags);
 	tfcp_req->active = false;
-	spin_unlock(&tfcp_req->reqlock);
+	spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 
 	tgt_fcpreq->transferred_length = xfrlen;
 	tgt_fcpreq->fcp_error = fcp_err;
@@ -682,15 +686,16 @@ fcloop_tgt_fcp_abort(struct nvmet_fc_target_port *tgtport,
 			struct nvmefc_tgt_fcp_req *tgt_fcpreq)
 {
 	struct fcloop_fcpreq *tfcp_req = tgt_fcp_req_to_fcpreq(tgt_fcpreq);
+	unsigned long flags;
 
 	/*
 	 * mark aborted only in case there were 2 threads in transport
 	 * (one doing io, other doing abort) and only kills ops posted
 	 * after the abort request
 	 */
-	spin_lock(&tfcp_req->reqlock);
+	spin_lock_irqsave(&tfcp_req->reqlock, flags);
 	tfcp_req->aborted = true;
-	spin_unlock(&tfcp_req->reqlock);
+	spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 
 	tfcp_req->status = NVME_SC_INTERNAL;
 
@@ -726,19 +731,20 @@ fcloop_fcp_abort(struct nvme_fc_local_port *localport,
 	struct fcloop_ini_fcpreq *inireq = fcpreq->private;
 	struct fcloop_fcpreq *tfcp_req;
 	bool abortio = true;
+	unsigned long flags;
 
-	spin_lock(&inireq->inilock);
+	spin_lock_irqsave(&inireq->inilock, flags);
 	tfcp_req = inireq->tfcp_req;
 	if (tfcp_req)
 		fcloop_tfcp_req_get(tfcp_req);
-	spin_unlock(&inireq->inilock);
+	spin_unlock_irqrestore(&inireq->inilock, flags);
 
 	if (!tfcp_req)
 		/* abort has already been called */
 		return;
 
 	/* break initiator/target relationship for io */
-	spin_lock(&tfcp_req->reqlock);
+	spin_lock_irqsave(&tfcp_req->reqlock, flags);
 	switch (tfcp_req->inistate) {
 	case INI_IO_START:
 	case INI_IO_ACTIVE:
@@ -748,11 +754,11 @@ fcloop_fcp_abort(struct nvme_fc_local_port *localport,
 		abortio = false;
 		break;
 	default:
-		spin_unlock(&tfcp_req->reqlock);
+		spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 		WARN_ON(1);
 		return;
 	}
-	spin_unlock(&tfcp_req->reqlock);
+	spin_unlock_irqrestore(&tfcp_req->reqlock, flags);
 
 	if (abortio)
 		/* leave the reference while the work item is scheduled */
-- 
2.16.3




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