[PATCH v4 5/7] scsi: ipr: Eliminate duplicate barriers on weakly-ordered archs
From: Sinan Kaya <hidden>
Date: 2018-03-20 02:51:20
Also in:
linux-arm-msm, linux-scsi, lkml
Subsystem:
ibm power linux raid adapter, scsi subsystem, the rest · Maintainers:
Brian King, "James E.J. Bottomley", "Martin K. Petersen", Linus Torvalds
Code includes barrier() followed by writel(). writel() already has a barrier on some architectures like arm64. This ends up CPU observing two barriers back to back before executing the register write. Since code already has an explicit barrier call, changing writeX() to writeX_relaxed(). Signed-off-by: Sinan Kaya <redacted> --- drivers/scsi/ipr.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index e07dd99..209adac 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c@@ -762,9 +762,9 @@ static void ipr_mask_and_clear_interrupts(struct ipr_ioa_cfg *ioa_cfg, /* Set interrupt mask to stop all new interrupts */ if (ioa_cfg->sis64) - writeq(~0, ioa_cfg->regs.set_interrupt_mask_reg); + writeq_relaxed(~0, ioa_cfg->regs.set_interrupt_mask_reg); else - writel(~0, ioa_cfg->regs.set_interrupt_mask_reg); + writel_relaxed(~0, ioa_cfg->regs.set_interrupt_mask_reg); /* Clear any pending interrupts */ if (ioa_cfg->sis64)
@@ -8435,7 +8435,8 @@ static int ipr_reset_enable_ioa(struct ipr_cmnd *ipr_cmd) wmb(); if (ioa_cfg->sis64) { /* Set the adapter to the correct endian mode. */ - writel(IPR_ENDIAN_SWAP_KEY, ioa_cfg->regs.endian_swap_reg); + writel_relaxed(IPR_ENDIAN_SWAP_KEY, + ioa_cfg->regs.endian_swap_reg); int_reg = readl(ioa_cfg->regs.endian_swap_reg); }
--
2.7.4