From 36ea79577bd1fa9dfe5b0a2d81072335ce2c0074 Mon Sep 17 00:00:00 2001 From: Sinan Kaya Date: Fri, 7 Apr 2017 15:06:18 -0400 Subject: [PATCH] scsi: mpt3sas: remove redundant wmb Due to relaxed ordering requirements on multiple architectures, drivers are required to use wmb/rmb/mb combinations when they need to guarantee observability between the memory and the HW. The mpt3sas driver is already using wmb() for this purpose. However, it issues a writel following wmb(). writel() function on arm/arm64 arhictectures have an embedded wmb() call inside. This results in unnecessary performance loss and code duplication. writel already guarantees ordering for both cpu and bus. we don't need additional wmb() Signed-off-by: Sinan Kaya Acked-by: Sreekanth Reddy Reviewed-by: Brian King Signed-off-by: Martin K. Petersen --- drivers/scsi/mpt3sas/mpt3sas_base.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c index 5b7aec5d575a3..18039bba26c43 100644 --- a/drivers/scsi/mpt3sas/mpt3sas_base.c +++ b/drivers/scsi/mpt3sas/mpt3sas_base.c @@ -1025,7 +1025,6 @@ _base_interrupt(int irq, void *bus_id) 0 : ioc->reply_free_host_index + 1; ioc->reply_free[ioc->reply_free_host_index] = cpu_to_le32(reply); - wmb(); writel(ioc->reply_free_host_index, &ioc->chip->ReplyFreeHostIndex); } @@ -1074,7 +1073,6 @@ _base_interrupt(int irq, void *bus_id) return IRQ_NONE; } - wmb(); if (ioc->is_warpdrive) { writel(reply_q->reply_post_host_index, ioc->reply_post_host_index[msix_index]); -- 2.39.5