Commit 5c08c5ac authored by John Garry's avatar John Garry Committed by Will Deacon
Browse files

iommu/arm-smmu-v3: Remove some unneeded init in arm_smmu_cmdq_issue_cmdlist() 



Members of struct "llq" will be zero-inited, apart from member max_n_shift.
But we write llq.val straight after the init, so it was pointless to zero
init those other members. As such, separately init member max_n_shift
only.

In addition, struct "head" is initialised to "llq" only so that member
max_n_shift is set. But that member is never referenced for "head", so
remove any init there.

Removing these initializations is seen as a small performance optimisation,
as this code is (very) hot path.

Signed-off-by: default avatarJohn Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1624293394-202509-1-git-send-email-john.garry@huawei.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent ff117646

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

+3 −3
Original line number Diff line number Diff line
@@ -733,11 +733,11 @@ static int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu, 
	unsigned long flags;

	bool owner;

	struct arm_smmu_cmdq *cmdq = &smmu->cmdq;

	struct arm_smmu_ll_queue llq = {

		.max_n_shift = cmdq->q.llq.max_n_shift,

	}, head = llq;

	struct arm_smmu_ll_queue llq, head;

	int ret = 0;



	llq.max_n_shift = cmdq->q.llq.max_n_shift;



	/* 1. Allocate some space in the queue */

	local_irq_save(flags);

	llq.val = READ_ONCE(cmdq->q.llq.val);