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Message-Id: <20240215162327.3663092-2-sean.anderson@seco.com>
Date: Thu, 15 Feb 2024 11:23:27 -0500
From: Sean Anderson <sean.anderson@...o.com>
To: "David S . Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
netdev@...r.kernel.org
Cc: linuxppc-dev@...ts.ozlabs.org,
Steffen Trumtrar <s.trumtrar@...gutronix.de>,
linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
Roy Pledge <roy.pledge@....com>,
Vladimir Oltean <vladimir.oltean@....com>,
Li Yang <leoyang.li@....com>,
Camelia Groza <camelia.groza@....com>,
Claudiu Manoil <claudiu.manoil@....com>,
Scott Wood <oss@...error.net>,
Sean Anderson <sean.anderson@...o.com>,
stable@...r.kernel.org
Subject: [RESEND PATCH net v4 2/2] soc: fsl: qbman: Use raw spinlock for cgr_lock
cgr_lock may be locked with interrupts already disabled by
smp_call_function_single. As such, we must use a raw spinlock to avoid
problems on PREEMPT_RT kernels. Although this bug has existed for a
while, it was not apparent until commit ef2a8d5478b9 ("net: dpaa: Adjust
queue depth on rate change") which invokes smp_call_function_single via
qman_update_cgr_safe every time a link goes up or down.
Fixes: 96f413f47677 ("soc/fsl/qbman: fix issue in qman_delete_cgr_safe()")
CC: stable@...r.kernel.org
Reported-by: Vladimir Oltean <vladimir.oltean@....com>
Closes: https://lore.kernel.org/all/20230323153935.nofnjucqjqnz34ej@skbuf/
Reported-by: Steffen Trumtrar <s.trumtrar@...gutronix.de>
Closes: https://lore.kernel.org/linux-arm-kernel/87wmsyvclu.fsf@pengutronix.de/
Signed-off-by: Sean Anderson <sean.anderson@...o.com>
Reviewed-by: Camelia Groza <camelia.groza@....com>
Tested-by: Vladimir Oltean <vladimir.oltean@....com>
---
Changes in v4:
- Add a note about how raw spinlocks aren't quite right
Changes in v3:
- Change blamed commit to something more appropriate
drivers/soc/fsl/qbman/qman.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c
index 1bf1f1ea67f0..7e9074519ad2 100644
--- a/drivers/soc/fsl/qbman/qman.c
+++ b/drivers/soc/fsl/qbman/qman.c
@@ -991,7 +991,7 @@ struct qman_portal {
/* linked-list of CSCN handlers. */
struct list_head cgr_cbs;
/* list lock */
- spinlock_t cgr_lock;
+ raw_spinlock_t cgr_lock;
struct work_struct congestion_work;
struct work_struct mr_work;
char irqname[MAX_IRQNAME];
@@ -1281,7 +1281,7 @@ static int qman_create_portal(struct qman_portal *portal,
/* if the given mask is NULL, assume all CGRs can be seen */
qman_cgrs_fill(&portal->cgrs[0]);
INIT_LIST_HEAD(&portal->cgr_cbs);
- spin_lock_init(&portal->cgr_lock);
+ raw_spin_lock_init(&portal->cgr_lock);
INIT_WORK(&portal->congestion_work, qm_congestion_task);
INIT_WORK(&portal->mr_work, qm_mr_process_task);
portal->bits = 0;
@@ -1456,11 +1456,14 @@ static void qm_congestion_task(struct work_struct *work)
union qm_mc_result *mcr;
struct qman_cgr *cgr;
- spin_lock_irq(&p->cgr_lock);
+ /*
+ * FIXME: QM_MCR_TIMEOUT is 10ms, which is too long for a raw spinlock!
+ */
+ raw_spin_lock_irq(&p->cgr_lock);
qm_mc_start(&p->p);
qm_mc_commit(&p->p, QM_MCC_VERB_QUERYCONGESTION);
if (!qm_mc_result_timeout(&p->p, &mcr)) {
- spin_unlock_irq(&p->cgr_lock);
+ raw_spin_unlock_irq(&p->cgr_lock);
dev_crit(p->config->dev, "QUERYCONGESTION timeout\n");
qman_p_irqsource_add(p, QM_PIRQ_CSCI);
return;
@@ -1476,7 +1479,7 @@ static void qm_congestion_task(struct work_struct *work)
list_for_each_entry(cgr, &p->cgr_cbs, node)
if (cgr->cb && qman_cgrs_get(&c, cgr->cgrid))
cgr->cb(p, cgr, qman_cgrs_get(&rr, cgr->cgrid));
- spin_unlock_irq(&p->cgr_lock);
+ raw_spin_unlock_irq(&p->cgr_lock);
qman_p_irqsource_add(p, QM_PIRQ_CSCI);
}
@@ -2440,7 +2443,7 @@ int qman_create_cgr(struct qman_cgr *cgr, u32 flags,
preempt_enable();
cgr->chan = p->config->channel;
- spin_lock_irq(&p->cgr_lock);
+ raw_spin_lock_irq(&p->cgr_lock);
if (opts) {
struct qm_mcc_initcgr local_opts = *opts;
@@ -2477,7 +2480,7 @@ int qman_create_cgr(struct qman_cgr *cgr, u32 flags,
qman_cgrs_get(&p->cgrs[1], cgr->cgrid))
cgr->cb(p, cgr, 1);
out:
- spin_unlock_irq(&p->cgr_lock);
+ raw_spin_unlock_irq(&p->cgr_lock);
put_affine_portal();
return ret;
}
@@ -2512,7 +2515,7 @@ int qman_delete_cgr(struct qman_cgr *cgr)
return -EINVAL;
memset(&local_opts, 0, sizeof(struct qm_mcc_initcgr));
- spin_lock_irqsave(&p->cgr_lock, irqflags);
+ raw_spin_lock_irqsave(&p->cgr_lock, irqflags);
list_del(&cgr->node);
/*
* If there are no other CGR objects for this CGRID in the list,
@@ -2537,7 +2540,7 @@ int qman_delete_cgr(struct qman_cgr *cgr)
/* add back to the list */
list_add(&cgr->node, &p->cgr_cbs);
release_lock:
- spin_unlock_irqrestore(&p->cgr_lock, irqflags);
+ raw_spin_unlock_irqrestore(&p->cgr_lock, irqflags);
put_affine_portal();
return ret;
}
@@ -2577,9 +2580,9 @@ static int qman_update_cgr(struct qman_cgr *cgr, struct qm_mcc_initcgr *opts)
if (!p)
return -EINVAL;
- spin_lock_irqsave(&p->cgr_lock, irqflags);
+ raw_spin_lock_irqsave(&p->cgr_lock, irqflags);
ret = qm_modify_cgr(cgr, 0, opts);
- spin_unlock_irqrestore(&p->cgr_lock, irqflags);
+ raw_spin_unlock_irqrestore(&p->cgr_lock, irqflags);
put_affine_portal();
return ret;
}
--
2.35.1.1320.gc452695387.dirty
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