From mboxrd@z Thu Jan 1 00:00:00 1970 From: jgg@ziepe.ca (Jason Gunthorpe) Date: Tue, 13 Mar 2018 22:12:49 -0600 Subject: [PATCH 3/7] RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs In-Reply-To: <1520997629-17361-3-git-send-email-okaya@codeaurora.org> References: <1520997629-17361-1-git-send-email-okaya@codeaurora.org> <1520997629-17361-3-git-send-email-okaya@codeaurora.org> Message-ID: <20180314041249.GA18314@ziepe.ca> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Mar 13, 2018 at 11:20:24PM -0400, Sinan Kaya wrote: > Code includes wmb() followed by writel() in multiple places. 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 writel() to > writel_relaxed(). > > Signed-off-by: Sinan Kaya > drivers/infiniband/hw/qedr/verbs.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Sure matches my understanding of writel_relaxed This is part of a series, should we take just this patch through the rdma tree? If not: Acked-by: Jason Gunthorpe Thanks, Jason