Commit 9cff922b authored by Jean-Philippe Brucker's avatar Jean-Philippe Brucker Committed by Will Deacon
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iommu/arm-smmu-v3: Ratelimit event dump 



When a device or driver misbehaves, it is possible to receive DMA fault
events much faster than we can print them out, causing a lock up of the
system and inability to cancel the source of the problem. Ratelimit
printing of events to help recovery.

Tested-by: default avatarAaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20210531095648.118282-1-jean-philippe@linaro.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 395ad89d

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

+3 −1
Original line number Diff line number Diff line
@@ -1518,6 +1518,8 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev) 
	struct arm_smmu_device *smmu = dev;

	struct arm_smmu_queue *q = &smmu->evtq.q;

	struct arm_smmu_ll_queue *llq = &q->llq;

	static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,

				      DEFAULT_RATELIMIT_BURST);

	u64 evt[EVTQ_ENT_DWORDS];



	do {
@@ -1525,7 +1527,7 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev) 
			u8 id = FIELD_GET(EVTQ_0_ID, evt[0]);



			ret = arm_smmu_handle_evt(smmu, evt);

			if (!ret)

			if (!ret || !__ratelimit(&rs))

				continue;



			dev_info(smmu->dev, "event 0x%02x received:\n", id);