[PATCH AUTOSEL 4.20 12/81] soc: fsl: qbman: avoid race in clearing QMan interrupt

Sasha Levin
2019-02-28T15:34:09Z

From: Madalin Bucur <madalin.bucur@nxp.com>

[ Upstream commit 89857a8a5c89a406b967ab2be7bd2ccdbe75e73d ]

By clearing all interrupt sources, not only those that
already occurred, the existing code may acknowledge by
mistake interrupts that occurred after the code checks
for them.

Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: Roy Pledge <roy.pledge@nxp.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/soc/fsl/qbman/qman.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c
index 5ce24718c2fd1..d8b3ba047c28f 100644
--- a/drivers/soc/fsl/qbman/qman.c
+++ b/drivers/soc/fsl/qbman/qman.c
@@ -1124,18 +1124,19 @@ static void qm_mr_process_task(struct work_struct *work);
static irqreturn_t portal_isr(int irq, void *ptr)
{
struct qman_portal *p = ptr;
-
- u32 clear = QM_DQAVAIL_MASK | p->irq_sources;
u32 is = qm_in(&p->p, QM_REG_ISR) & p->irq_sources;
+ u32 clear = 0;

if (unlikely(!is))
return IRQ_NONE;

/* DQRR-handling if it's interrupt-driven */
- if (is & QM_PIRQ_DQRI)
+ if (is & QM_PIRQ_DQRI) {
__poll_portal_fast(p, QMAN_POLL_LIMIT);
+ clear = QM_DQAVAIL_MASK | QM_PIRQ_DQRI;
+ }
/* Handling of anything else that's interrupt-driven */
- clear |= __poll_portal_slow(p, is);
+ clear |= __poll_portal_slow(p, is) & QM_PIRQ_SLOW;
qm_out(&p->p, QM_REG_ISR, clear);
return IRQ_HANDLED;
}
--
2.19.1