* [PATCH 2/2] soc: fsl: qbman: Use raw spinlock for cgr_lock
2023-03-27 19:28 [PATCH 1/2] soc: fsl: qbman: Always disable interrupts when taking cgr_lock Sean Anderson
@ 2023-03-27 19:28 ` Sean Anderson
2023-03-31 10:58 ` [PATCH 1/2] soc: fsl: qbman: Always disable interrupts when taking cgr_lock Camelia Alexandra Groza
1 sibling, 0 replies; 4+ messages in thread
From: Sean Anderson @ 2023-03-27 19:28 UTC (permalink / raw)
To: Li Yang, linuxppc-dev, linux-arm-kernel
Cc: Sean Anderson, Vladimir Oltean, Roy Pledge, linux-kernel,
Scott Wood, Claudiu Manoil, Camelia Groza, David S . Miller
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: c535e923bb97 ("soc/fsl: Introduce DPAA 1.x QMan device driver")
Reported-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/all/20230323153935.nofnjucqjqnz34ej@skbuf/
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
---
drivers/soc/fsl/qbman/qman.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c
index ff870ca07596..cf8606108a81 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 +1456,11 @@ static void qm_congestion_task(struct work_struct *work)
union qm_mc_result *mcr;
struct qman_cgr *cgr;
- spin_lock_irq(&p->cgr_lock);
+ 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(&p->cgr_lock);
+ raw_spin_unlock(&p->cgr_lock);
dev_crit(p->config->dev, "QUERYCONGESTION timeout\n");
qman_p_irqsource_add(p, QM_PIRQ_CSCI);
return;
@@ -1476,7 +1476,7 @@ 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 +2440,7 @@ 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 +2477,7 @@ 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 +2512,7 @@ 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 +2537,7 @@ 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 +2577,9 @@ 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
^ permalink raw reply related [flat|nested] 4+ messages in thread* RE: [PATCH 1/2] soc: fsl: qbman: Always disable interrupts when taking cgr_lock
2023-03-27 19:28 [PATCH 1/2] soc: fsl: qbman: Always disable interrupts when taking cgr_lock Sean Anderson
2023-03-27 19:28 ` [PATCH 2/2] soc: fsl: qbman: Use raw spinlock for cgr_lock Sean Anderson
@ 2023-03-31 10:58 ` Camelia Alexandra Groza
2023-03-31 14:55 ` Sean Anderson
1 sibling, 1 reply; 4+ messages in thread
From: Camelia Alexandra Groza @ 2023-03-31 10:58 UTC (permalink / raw)
To: Sean Anderson, Leo Li, linuxppc-dev, linux-arm-kernel
Cc: Sean Anderson, Vladimir Oltean, Roy Pledge, linux-kernel,
Scott Wood, Claudiu Manoil, David S . Miller
> -----Original Message-----
> From: Sean Anderson <sean.anderson@seco.com>
> Sent: Monday, March 27, 2023 22:29
> To: Leo Li <leoyang.li@nxp.com>; linuxppc-dev@lists.ozlabs.org; linux-arm-
> kernel@lists.infradead.org
> Cc: Scott Wood <oss@buserror.net>; linux-kernel@vger.kernel.org; David S .
> Miller <davem@davemloft.net>; Claudiu Manoil <claudiu.manoil@nxp.com>;
> Roy Pledge <roy.pledge@nxp.com>; Vladimir Oltean
> <vladimir.oltean@nxp.com>; Camelia Alexandra Groza
> <camelia.groza@nxp.com>; Sean Anderson <sean.anderson@seco.com>
> Subject: [PATCH 1/2] soc: fsl: qbman: Always disable interrupts when taking
> cgr_lock
>
> smp_call_function_single disables IRQs when executing the callback. To
> prevent deadlocks, we must disable IRQs when taking cgr_lock elsewhere.
> This is already done by qman_update_cgr and qman_delete_cgr; fix the
> other lockers.
>
> Fixes: c535e923bb97 ("soc/fsl: Introduce DPAA 1.x QMan device driver")
> Signed-off-by: Sean Anderson <sean.anderson@seco.com>
> ---
>
> drivers/soc/fsl/qbman/qman.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c
> index 739e4eee6b75..ff870ca07596 100644
> --- a/drivers/soc/fsl/qbman/qman.c
> +++ b/drivers/soc/fsl/qbman/qman.c
> @@ -1456,7 +1456,7 @@ static void qm_congestion_task(struct work_struct
> *work)
> union qm_mc_result *mcr;
> struct qman_cgr *cgr;
>
> - spin_lock(&p->cgr_lock);
> + 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)) {
> @@ -1476,7 +1476,7 @@ 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(&p->cgr_lock);
> + spin_unlock_irq(&p->cgr_lock);
> qman_p_irqsource_add(p, QM_PIRQ_CSCI);
> }
There is one more spin_unlock call in qm_congestion_task on the error path that needs updating:
if (!qm_mc_result_timeout(&p->p, &mcr)) {
spin_unlock(&p->cgr_lock);
Regards,
Camelia
> @@ -2440,7 +2440,7 @@ int qman_create_cgr(struct qman_cgr *cgr, u32
> flags,
> preempt_enable();
>
> cgr->chan = p->config->channel;
> - spin_lock(&p->cgr_lock);
> + spin_lock_irq(&p->cgr_lock);
>
> if (opts) {
> struct qm_mcc_initcgr local_opts = *opts;
> @@ -2477,7 +2477,7 @@ 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(&p->cgr_lock);
> + spin_unlock_irq(&p->cgr_lock);
> put_affine_portal();
> return ret;
> }
> --
> 2.35.1.1320.gc452695387.dirty
^ permalink raw reply [flat|nested] 4+ messages in thread