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* [PATCH] iommu/arm-smmu-v3: Stop pre-zeroing batch commands in arm_smmu_atc_inv_master()
@ 2021-08-17 11:34 Zhen Lei
  2021-08-17 11:53 ` John Garry
  2021-10-04 12:05 ` Will Deacon
  0 siblings, 2 replies; 3+ messages in thread
From: Zhen Lei @ 2021-08-17 11:34 UTC (permalink / raw)
  To: Will Deacon, Robin Murphy, Joerg Roedel, linux-arm-kernel, iommu,
	linux-kernel
  Cc: Zhen Lei, John Garry

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 <thunder.leizhen@huawei.com>
---
 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;
 	for (i = 0; i < master->num_streams; i++) {
 		cmd.atc.sid = master->streams[i].id;
 		arm_smmu_cmdq_batch_add(master->smmu, &cmds, &cmd);
-- 
2.26.0.106.g9fadedd


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] iommu/arm-smmu-v3: Stop pre-zeroing batch commands in arm_smmu_atc_inv_master()
  2021-08-17 11:34 [PATCH] iommu/arm-smmu-v3: Stop pre-zeroing batch commands in arm_smmu_atc_inv_master() Zhen Lei
@ 2021-08-17 11:53 ` John Garry
  2021-10-04 12:05 ` Will Deacon
  1 sibling, 0 replies; 3+ messages in thread
From: John Garry @ 2021-08-17 11:53 UTC (permalink / raw)
  To: Zhen Lei, Will Deacon, Robin Murphy, Joerg Roedel,
	linux-arm-kernel, iommu, linux-kernel

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 <thunder.leizhen@huawei.com>

Reviewed-by: John Garry <john.garry@huawei.com>

> ---
>   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);
> 


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] iommu/arm-smmu-v3: Stop pre-zeroing batch commands in arm_smmu_atc_inv_master()
  2021-08-17 11:34 [PATCH] iommu/arm-smmu-v3: Stop pre-zeroing batch commands in arm_smmu_atc_inv_master() Zhen Lei
  2021-08-17 11:53 ` John Garry
@ 2021-10-04 12:05 ` Will Deacon
  1 sibling, 0 replies; 3+ messages in thread
From: Will Deacon @ 2021-10-04 12:05 UTC (permalink / raw)
  To: linux-kernel, Robin Murphy, Joerg Roedel, linux-arm-kernel,
	Zhen Lei, iommu
  Cc: catalin.marinas, kernel-team, Will Deacon, John Garry

On Tue, 17 Aug 2021 19:34:11 +0800, 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.
> 
> 

Applied to will (for-joerg/arm-smmu/updates), thanks!

[1/1] iommu/arm-smmu-v3: Stop pre-zeroing batch commands in arm_smmu_atc_inv_master()
      https://git.kernel.org/will/c/93f9f7958f12

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-10-04 12:05 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-17 11:34 [PATCH] iommu/arm-smmu-v3: Stop pre-zeroing batch commands in arm_smmu_atc_inv_master() Zhen Lei
2021-08-17 11:53 ` John Garry
2021-10-04 12:05 ` Will Deacon

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