From f2233a33dc1fef4aa30dc11e4c676637bf358c3d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 19 Mar 2018 22:50:05 -0400 Subject: [PATCH] scsi: ipr: Eliminate duplicate barriers Driver does both wmb() and writel(). The latter already has a barrier on some architectures like arm64. This ends up with CPU observing two barriers back to back before executing the register write. Drivers should generally assume that the barrier implied by writel() is sufficient for ordering DMA. Remove the extraneous wmb() before it. [mkp: Squashed Arnd's and Sinan's patches] Signed-off-by: Arnd Bergmann Reported-by: Sinan Kaya Acked-by: Brian King Signed-off-by: Martin K. Petersen --- drivers/scsi/ipr.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c index 0a9b8b3..02d65dc 100644 --- a/drivers/scsi/ipr.c +++ b/drivers/scsi/ipr.c @@ -760,7 +760,6 @@ static void ipr_mask_and_clear_interrupts(struct ipr_ioa_cfg *ioa_cfg, ioa_cfg->hrrq[i].allow_interrupts = 0; spin_unlock(&ioa_cfg->hrrq[i]._lock); } - wmb(); /* Set interrupt mask to stop all new interrupts */ if (ioa_cfg->sis64) @@ -8403,7 +8402,6 @@ static int ipr_reset_enable_ioa(struct ipr_cmnd *ipr_cmd) ioa_cfg->hrrq[i].allow_interrupts = 1; spin_unlock(&ioa_cfg->hrrq[i]._lock); } - wmb(); if (ioa_cfg->sis64) { /* Set the adapter to the correct endian mode. */ writel(IPR_ENDIAN_SWAP_KEY, ioa_cfg->regs.endian_swap_reg); -- 2.7.4