On Wed, Aug 11, 2021 at 11:31:08AM +0100, John Garry wrote:
> > > > > Obviously, inserting as many commands at a time as possible can
> > > > > reduce the
> > > > > number of times the mutex contention participates, thereby improving
> > > > > the
> > > > > overall performance. At least it reduces the number of calls to
> > > > > function
> > > > > arm_smmu_cmdq_issue_cmdlist().
> > > > >
> > > > > Therefore, function arm_smmu_cmdq_issue_cmd_with_sync() is added to
> > > > > insert
> > > > > the 'cmd+sync' commands at a time.
> > > > >
> > > > > Signed-off-by: Zhen Lei <thunder.leiz...@huawei.com>
> > > > > ---
> > > > > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 33
> > > > > +++++++++++++--------
> > > > > 1 file changed, 21 insertions(+), 12 deletions(-)
> > > > >
> > > > > 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 2433d3c29b49ff2..a5361153ca1d6a4 100644
> > > > > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > > > > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > > > > @@ -858,11 +858,25 @@ static int arm_smmu_cmdq_issue_cmd(struct
> > > > > arm_smmu_device *smmu,
> > > > > return arm_smmu_cmdq_issue_cmdlist(smmu, cmd, 1, false);
> > > > > }
> > > > > -static int arm_smmu_cmdq_issue_sync(struct arm_smmu_device *smmu)
> > > > > +static int __maybe_unused arm_smmu_cmdq_issue_sync(struct
> > > > > arm_smmu_device *smmu)
> > > > > {
> > > > > return arm_smmu_cmdq_issue_cmdlist(smmu, NULL, 0, true);
> > > > > }
> > > > > +static int arm_smmu_cmdq_issue_cmd_with_sync(struct arm_smmu_device
> > > > > *smmu,
> > > > > + struct arm_smmu_cmdq_ent
> > > > > *ent)
> > > > > +{
> > > > > + u64 cmd[CMDQ_ENT_DWORDS];
> > > > > +
> > > > > + if (arm_smmu_cmdq_build_cmd(cmd, ent)) {
> > > > > + dev_warn(smmu->dev, "ignoring unknown CMDQ opcode
> > > > > 0x%x\n",
> > > > > + ent->opcode);
> > > > > + return -EINVAL;
>
> Are any of the errors returned from the "issue command" functions actually
> consumed? I couldn't see it on mainline code from a brief browse.
I don't think so. Can we actually propagate them?
Will
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