Re: [PATCH] iommu/arm-smmu-v3: Stop pre-zeroing batch commands in arm_smmu_atc_inv_master()
From: John Garry <hidden>
Date: 2021-08-17 11:53:58
Also in:
linux-iommu, lkml
On 17/08/2021 12:34, Zhen Lei wrote:
Pre-zeroing the batched commands structure is inefficient, as individual commands are zeroed later in arm_smmu_cmdq_build_cmd(). Therefore, only the member 'num' needs to be initialized to 0. Signed-off-by: Zhen Lei <redacted>
Reviewed-by: John Garry <redacted>
quoted hunk ↗ jump to hunk
--- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index 50a9db5bac466c7..e6882ae81fd08f6 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c@@ -1776,10 +1776,11 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master) { int i; struct arm_smmu_cmdq_ent cmd; - struct arm_smmu_cmdq_batch cmds = {}; + struct arm_smmu_cmdq_batch cmds; arm_smmu_atc_inv_to_cmd(0, 0, 0, &cmd); + cmds.num = 0;
We prob should have added a comment why we do this (and at the other sites). I think Robin said something similar in another patch.
for (i = 0; i < master->num_streams; i++) {
cmd.atc.sid = master->streams[i].id;
arm_smmu_cmdq_batch_add(master->smmu, &cmds, &cmd);_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel