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Commit 07560409 authored by Sumit.Saxena@avagotech.com's avatar Sumit.Saxena@avagotech.com Committed by Christoph Hellwig
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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: default avatarSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: default avatarKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: default avatarTomas Henzl <thenzl@redhat.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 07e38d94

drivers/scsi/megaraid/megaraid_sas_fusion.c

+6 −0
Original line number Diff line number Diff line
@@ -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

}



/**