From 0756040952582c4e7c2f23ff2af882c0f0c7a516 Mon Sep 17 00:00:00 2001 From: "Sumit.Saxena@avagotech.com" Date: Fri, 12 Sep 2014 18:57:18 +0530 Subject: [PATCH] megaraid_sas : Use writeq for 64bit pci write to avoid spinlock overhead Resending the patch. Addressed the review comments from Tomas Henzl. Reduce the assingment for u64 req_data variable. Use writeq() for 64bit PCI write instead of writel() to avoid additional lock overhead. Signed-off-by: Sumit Saxena Signed-off-by: Kashyap Desai Reviewed-by: Tomas Henzl Signed-off-by: Christoph Hellwig --- drivers/scsi/megaraid/megaraid_sas_fusion.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c b/drivers/scsi/megaraid/megaraid_sas_fusion.c index 57b47fe69072..8898817eaf8b 100644 --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c @@ -1065,6 +1065,11 @@ megasas_fire_cmd_fusion(struct megasas_instance *instance, u32 req_desc_hi, struct megasas_register_set __iomem *regs) { +#if defined(writeq) && defined(CONFIG_64BIT) + u64 req_data = (((u64)req_desc_hi << 32) | (u32)req_desc_lo); + + writeq(le64_to_cpu(req_data), &(regs)->inbound_low_queue_port); +#else unsigned long flags; spin_lock_irqsave(&instance->hba_lock, flags); @@ -1072,6 +1077,7 @@ megasas_fire_cmd_fusion(struct megasas_instance *instance, writel(le32_to_cpu(req_desc_lo), &(regs)->inbound_low_queue_port); writel(le32_to_cpu(req_desc_hi), &(regs)->inbound_high_queue_port); spin_unlock_irqrestore(&instance->hba_lock, flags); +#endif } /**