Commit 59d9bd72 authored by Zhen Lei's avatar Zhen Lei Committed by Will Deacon
Browse files

iommu/arm-smmu-v3: Properly handle the return value of arm_smmu_cmdq_build_cmd() 



1. Build command CMD_SYNC cannot fail. So the return value can be ignored.
2. The arm_smmu_cmdq_build_cmd() almost never fails, the addition of
   "unlikely()" can optimize the instruction pipeline.
3. Check the return value in arm_smmu_cmdq_batch_add().

Signed-off-by: default avatarZhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210818080452.2079-2-thunder.leizhen@huawei.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 93f9f795

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

+12 −6
Original line number Diff line number Diff line
@@ -409,10 +409,7 @@ static void __arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu, 
		dev_err(smmu->dev, "\t0x%016llx\n", (unsigned long long)cmd[i]);



	/* Convert the erroneous command into a CMD_SYNC */

	if (arm_smmu_cmdq_build_cmd(cmd, &cmd_sync)) {

		dev_err(smmu->dev, "failed to convert to CMD_SYNC\n");

		return;

	}

	arm_smmu_cmdq_build_cmd(cmd, &cmd_sync);



	queue_write(Q_ENT(q, cons), cmd, q->ent_dwords);

}
@@ -860,7 +857,7 @@ static int __arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu, 
{

	u64 cmd[CMDQ_ENT_DWORDS];



	if (arm_smmu_cmdq_build_cmd(cmd, ent)) {

	if (unlikely(arm_smmu_cmdq_build_cmd(cmd, ent))) {

		dev_warn(smmu->dev, "ignoring unknown CMDQ opcode 0x%x\n",

			 ent->opcode);

		return -EINVAL;
@@ -885,11 +882,20 @@ static void arm_smmu_cmdq_batch_add(struct arm_smmu_device *smmu, 
				    struct arm_smmu_cmdq_batch *cmds,

				    struct arm_smmu_cmdq_ent *cmd)

{

	int index;



	if (cmds->num == CMDQ_BATCH_ENTRIES) {

		arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmds, cmds->num, false);

		cmds->num = 0;

	}

	arm_smmu_cmdq_build_cmd(&cmds->cmds[cmds->num * CMDQ_ENT_DWORDS], cmd);



	index = cmds->num * CMDQ_ENT_DWORDS;

	if (unlikely(arm_smmu_cmdq_build_cmd(&cmds->cmds[index], cmd))) {

		dev_warn(smmu->dev, "ignoring unknown CMDQ opcode 0x%x\n",

			 cmd->opcode);

		return;

	}



	cmds->num++;

}