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Subject[PATCH 4.19 04/49] scsi: qla2xxx: Reduce holding sess_lock to prevent CPU lock-up
Date
From: Quinn Tran <quinn.tran@cavium.com>

commit 0aca77843e2803bf4fab1598b7891c56c16be979 upstream.

- Reduce sess_lock holding to prevent CPU Lock up. sess_lock was held across
fc_port registration and deletion. These calls can be blocked by upper
layer. Sess_lock is also being accessed by interrupt thread.

- Reduce number of loops in processing work_list to prevent kernel complaint
of CPU lockup or holding sess_lock.

Reported-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn>
Tested-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn>
Fixes: 9ba1cb25c151 ("scsi: qla2xxx: Remove all rports if fabric scan retry fails")
Link: https://lore.kernel.org/linux-scsi/D01377DD-2E86-427B-BA0C-8D7649E37870@oracle.com/T/#t
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/qla2xxx/qla_def.h | 2 +-
drivers/scsi/qla2xxx/qla_gs.c | 18 ++++++++++++------
drivers/scsi/qla2xxx/qla_init.c | 33 +++++++++++++++++----------------
drivers/scsi/qla2xxx/qla_os.c | 3 +--
drivers/scsi/qla2xxx/qla_target.c | 2 ++
5 files changed, 33 insertions(+), 25 deletions(-)

--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -262,8 +262,8 @@ struct name_list_extended {
struct get_name_list_extended *l;
dma_addr_t ldma;
struct list_head fcports;
- spinlock_t fcports_lock;
u32 size;
+ u8 sent;
};
/*
* Timeout timer counts in seconds
--- a/drivers/scsi/qla2xxx/qla_gs.c
+++ b/drivers/scsi/qla2xxx/qla_gs.c
@@ -4018,11 +4018,10 @@ void qla24xx_async_gnnft_done(scsi_qla_h
if ((qla_dual_mode_enabled(vha) ||
qla_ini_mode_enabled(vha)) &&
atomic_read(&fcport->state) == FCS_ONLINE) {
- qla2x00_mark_device_lost(vha, fcport,
- ql2xplogiabsentdevice, 0);
+ if (fcport->loop_id != FC_NO_LOOP_ID) {
+ if (fcport->flags & FCF_FCP2_DEVICE)
+ fcport->logout_on_delete = 0;

- if (fcport->loop_id != FC_NO_LOOP_ID &&
- (fcport->flags & FCF_FCP2_DEVICE) == 0) {
ql_dbg(ql_dbg_disc, vha, 0x20f0,
"%s %d %8phC post del sess\n",
__func__, __LINE__,
@@ -4261,12 +4260,13 @@ static void qla2x00_async_gpnft_gnnft_sp

sp->rc = res;
rc = qla2x00_post_nvme_gpnft_done_work(vha, sp, QLA_EVT_GPNFT);
- if (!rc) {
+ if (rc) {
qla24xx_sp_unmap(vha, sp);
set_bit(LOCAL_LOOP_UPDATE, &vha->dpc_flags);
set_bit(LOOP_RESYNC_NEEDED, &vha->dpc_flags);
return;
}
+ return;
}

if (cmd == GPN_FT_CMD) {
@@ -4316,6 +4316,8 @@ static int qla24xx_async_gnnft(scsi_qla_
vha->scan.scan_flags &= ~SF_SCANNING;
spin_unlock_irqrestore(&vha->work_lock, flags);
WARN_ON(1);
+ set_bit(LOCAL_LOOP_UPDATE, &vha->dpc_flags);
+ set_bit(LOOP_RESYNC_NEEDED, &vha->dpc_flags);
goto done_free_sp;
}

@@ -4349,8 +4351,12 @@ static int qla24xx_async_gnnft(scsi_qla_
sp->done = qla2x00_async_gpnft_gnnft_sp_done;

rval = qla2x00_start_sp(sp);
- if (rval != QLA_SUCCESS)
+ if (rval != QLA_SUCCESS) {
+ spin_lock_irqsave(&vha->work_lock, flags);
+ vha->scan.scan_flags &= ~SF_SCANNING;
+ spin_unlock_irqrestore(&vha->work_lock, flags);
goto done_free_sp;
+ }

ql_dbg(ql_dbg_disc, vha, 0xffff,
"Async-%s hdl=%x FC4Type %x.\n", sp->name,
--- a/drivers/scsi/qla2xxx/qla_init.c
+++ b/drivers/scsi/qla2xxx/qla_init.c
@@ -800,6 +800,7 @@ qla24xx_async_gnl_sp_done(void *s, int r
if (res == QLA_FUNCTION_TIMEOUT)
return;

+ sp->fcport->flags &= ~(FCF_ASYNC_SENT|FCF_ASYNC_ACTIVE);
memset(&ea, 0, sizeof(ea));
ea.sp = sp;
ea.rc = res;
@@ -827,25 +828,24 @@ qla24xx_async_gnl_sp_done(void *s, int r
(loop_id & 0x7fff));
}

- spin_lock_irqsave(&vha->gnl.fcports_lock, flags);
+ spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);

INIT_LIST_HEAD(&h);
fcport = tf = NULL;
if (!list_empty(&vha->gnl.fcports))
list_splice_init(&vha->gnl.fcports, &h);
+ spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);

list_for_each_entry_safe(fcport, tf, &h, gnl_entry) {
list_del_init(&fcport->gnl_entry);
- spin_lock(&vha->hw->tgt.sess_lock);
+ spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
fcport->flags &= ~(FCF_ASYNC_SENT | FCF_ASYNC_ACTIVE);
- spin_unlock(&vha->hw->tgt.sess_lock);
+ spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);
ea.fcport = fcport;

qla2x00_fcport_event_handler(vha, &ea);
}
- spin_unlock_irqrestore(&vha->gnl.fcports_lock, flags);

- spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
/* create new fcport if fw has knowledge of new sessions */
for (i = 0; i < n; i++) {
port_id_t id;
@@ -878,6 +878,8 @@ qla24xx_async_gnl_sp_done(void *s, int r
}
}

+ spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
+ vha->gnl.sent = 0;
spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);

sp->free(sp);
@@ -897,27 +899,24 @@ int qla24xx_async_gnl(struct scsi_qla_ho
ql_dbg(ql_dbg_disc, vha, 0x20d9,
"Async-gnlist WWPN %8phC \n", fcport->port_name);

- spin_lock_irqsave(&vha->gnl.fcports_lock, flags);
- if (!list_empty(&fcport->gnl_entry)) {
- spin_unlock_irqrestore(&vha->gnl.fcports_lock, flags);
- rval = QLA_SUCCESS;
- goto done;
- }
-
- spin_lock(&vha->hw->tgt.sess_lock);
+ spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
+ fcport->flags |= FCF_ASYNC_SENT;
fcport->disc_state = DSC_GNL;
fcport->last_rscn_gen = fcport->rscn_gen;
fcport->last_login_gen = fcport->login_gen;
- spin_unlock(&vha->hw->tgt.sess_lock);

list_add_tail(&fcport->gnl_entry, &vha->gnl.fcports);
- spin_unlock_irqrestore(&vha->gnl.fcports_lock, flags);
+ if (vha->gnl.sent) {
+ spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);
+ return QLA_SUCCESS;
+ }
+ vha->gnl.sent = 1;
+ spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);

sp = qla2x00_get_sp(vha, fcport, GFP_KERNEL);
if (!sp)
goto done;

- fcport->flags |= FCF_ASYNC_SENT;
sp->type = SRB_MB_IOCB;
sp->name = "gnlist";
sp->gen1 = fcport->rscn_gen;
@@ -1204,7 +1203,9 @@ void __qla24xx_handle_gpdb_event(scsi_ql
vha->fcport_count++;
ea->fcport->login_succ = 1;

+ spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);
qla24xx_sched_upd_fcport(ea->fcport);
+ spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
} else if (ea->fcport->login_succ) {
/*
* We have an existing session. A late RSCN delivery
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -2719,7 +2719,7 @@ static void qla2x00_iocb_work_fn(struct
struct scsi_qla_host, iocb_work);
struct qla_hw_data *ha = vha->hw;
struct scsi_qla_host *base_vha = pci_get_drvdata(ha->pdev);
- int i = 20;
+ int i = 2;
unsigned long flags;

if (test_bit(UNLOADING, &base_vha->dpc_flags))
@@ -4606,7 +4606,6 @@ struct scsi_qla_host *qla2x00_create_hos

spin_lock_init(&vha->work_lock);
spin_lock_init(&vha->cmd_list_lock);
- spin_lock_init(&vha->gnl.fcports_lock);
init_waitqueue_head(&vha->fcport_waitQ);
init_waitqueue_head(&vha->vref_waitq);

--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -600,7 +600,9 @@ void qla2x00_async_nack_sp_done(void *s,
sp->fcport->login_succ = 1;

vha->fcport_count++;
+ spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);
qla24xx_sched_upd_fcport(sp->fcport);
+ spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
} else {
sp->fcport->login_retry = 0;
sp->fcport->disc_state = DSC_LOGIN_COMPLETE;

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