soc: fsl: qbman: avoid race in clearing QMan interrupt

[ 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>

diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c
index 8cc0151..a4ac607 100644 (file)
--- a/drivers/soc/fsl/qbman/qman.c
+++ b/drivers/soc/fsl/qbman/qman.c
@@ -1081,18 +1081,19 @@ 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;
 }