@@ -893,6 +893,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
struct arm_smmu_cmdq_ent *ent)
{
u64 cmd[CMDQ_ENT_DWORDS];
+ unsigned long flags;
bool wfe = !!(smmu->features & ARM_SMMU_FEAT_SEV);
struct arm_smmu_queue *q = &smmu->cmdq.q;
@@ -902,7 +903,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
return;
}
- spin_lock(&smmu->cmdq.lock);
+ spin_lock_irqsave(&smmu->cmdq.lock, flags);
while (queue_insert_raw(q, cmd) == -ENOSPC) {
if (queue_poll_cons(q, false, wfe))
dev_err_ratelimited(smmu->dev, "CMDQ timeout\n");
@@ -910,7 +911,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
if (ent->opcode == CMDQ_OP_CMD_SYNC && queue_poll_cons(q, true, wfe))
dev_err_ratelimited(smmu->dev, "CMD_SYNC timeout\n");
- spin_unlock(&smmu->cmdq.lock);
+ spin_unlock_irqrestore(&smmu->cmdq.lock, flags);
}
/* Context descriptor manipulation functions */
The cmdq lock is taken whenever we issue comments into the command queue, which can occur in IRQ context (as a result if unmap) or in process context (as a result of a threaded IRQ handler or device probe). This can lead to a theoretical deadlock if the interrupt handler performing the unmap hits whilst the lock is taken, so explicitly use the {irqsave,irqrestore} spin_lock accessors for the cmdq lock. Signed-off-by: Will Deacon <will.deacon@arm.com> --- drivers/iommu/arm-smmu-v3.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) -- 2.1.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel