Messages in this thread | | | Subject | Re: [PATCH v4 5/7] scsi: ipr: Eliminate duplicate barriers on weakly-ordered archs | From | Brian King <> | Date | Tue, 29 May 2018 15:45:52 -0500 |
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On 03/19/2018 09:50 PM, Sinan Kaya wrote: > 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 <okaya@codeaurora.org> > --- > 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); > } >
Looks fine to me. Thanks.
Acked-by: Brian King <brking@linux.vnet.ibm.com>
-- Brian King Power Linux I/O IBM Linux Technology Center
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