Pre-zeroing the batched commands structure is inefficient, as individual commands are zeroed later in arm_smmu_cmdq_build_cmd(). The size is quite large and commonly most commands won't even be used:
struct arm_smmu_cmdq_batch cmds = {}; 345c: 52800001 mov w1, #0x0 // #0 3460: d2808102 mov x2, #0x408 // #1032 3464: 910143a0 add x0, x29, #0x50 3468: 94000000 bl 0 <memset> Stop pre-zeroing the complete structure and only zero the num member. Signed-off-by: John Garry <john.ga...@huawei.com> 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 cbc57edfa4e2..2a4f3fb938f6 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -1082,7 +1082,7 @@ static void arm_smmu_sync_cd(struct arm_smmu_domain *smmu_domain, size_t i; unsigned long flags; struct arm_smmu_master *master; - struct arm_smmu_cmdq_batch cmds = {}; + struct arm_smmu_cmdq_batch cmds; struct arm_smmu_device *smmu = smmu_domain->smmu; struct arm_smmu_cmdq_ent cmd = { .opcode = CMDQ_OP_CFGI_CD, @@ -1092,6 +1092,8 @@ static void arm_smmu_sync_cd(struct arm_smmu_domain *smmu_domain, }, }; + cmds.num = 0; + spin_lock_irqsave(&smmu_domain->devices_lock, flags); list_for_each_entry(master, &smmu_domain->devices, domain_head) { for (i = 0; i < master->num_streams; i++) { @@ -1908,7 +1910,7 @@ int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid, unsigned long flags; struct arm_smmu_cmdq_ent cmd; struct arm_smmu_master *master; - struct arm_smmu_cmdq_batch cmds = {}; + struct arm_smmu_cmdq_batch cmds; if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_ATS)) return 0; @@ -1932,6 +1934,8 @@ int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid, arm_smmu_atc_inv_to_cmd(ssid, iova, size, &cmd); + cmds.num = 0; + spin_lock_irqsave(&smmu_domain->devices_lock, flags); list_for_each_entry(master, &smmu_domain->devices, domain_head) { if (!master->ats_enabled) @@ -1980,7 +1984,7 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd, struct arm_smmu_device *smmu = smmu_domain->smmu; unsigned long end = iova + size, num_pages = 0, tg = 0; size_t inv_range = granule; - struct arm_smmu_cmdq_batch cmds = {}; + struct arm_smmu_cmdq_batch cmds; if (!size) return; @@ -1998,6 +2002,8 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd, num_pages = size >> tg; } + cmds.num = 0; + while (iova < end) { if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) { /* -- 2.26.2 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu