| Message ID | 141de3c3278e280712d16d9ac9ab305c3b80a810.1534344167.git.robin.murphy@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iommu/arm-smmu-v3: Inline arm_smmu_cmdq_build_cmd() | expand |
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 1d647104bccc..94544cd9d929 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -776,7 +776,7 @@ static int queue_remove_raw(struct arm_smmu_queue *q, u64 *ent) } /* High-level queue accessors */ -static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent) +static inline int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent) { memset(cmd, 0, CMDQ_ENT_DWORDS << 3); cmd[0] |= FIELD_PREP(CMDQ_0_OP, ent->opcode);
Outside arm_smmu_cmdq_issue_cmd(), the only places we build a command are those in which we are generating a sync for various reasons. Given the circumstances, one might hope GCC to be clever enough to emit a specialisation which avoids running through the switch statement with a known constant opcode just to copy two dwords of mostly-static data, but apparently it needs a little more help. Explicitly marking arm_smmu_cmdq_build_cmd() as inline reduces these sync special cases from an out-of-line call to a neat handful of ALU instructions at the couple of relevant sites, yet squashing the full switch statement into arm_smmu_cmdq_issue_cmd() somehow has a knock-on effect across various other areas of the driver for a surprising overall code size reduction: text data bss dec hex filename 16951 648 8 17607 44c7 arm-smmu-v3.o.new 17199 648 8 17855 45bf arm-smmu-v3.o.old Signed-off-by: Robin Murphy <robin.murphy@arm.com> --- Having distilled this out of my pile of hacks, I'm fairly confident that it's a reasonable change. Nothing in the latest SVA branch seems to have any adverse effect either, which is reassuring. drivers/iommu/arm-smmu-v3.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)