LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Sinan Kaya <okaya@codeaurora.org>
To: linux-scsi@vger.kernel.org, timur@codeaurora.org, sulrich@codeaurora.org
Cc: linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Sinan Kaya <okaya@codeaurora.org>,
	Adaptec OEM Raid Solutions <aacraid@adaptec.com>,
	"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v4 3/7] scsi: dpt_i2o: eliminate duplicate barriers on weakly-ordered archs
Date: Mon, 19 Mar 2018 22:50:03 -0400	[thread overview]
Message-ID: <1521514207-10695-4-git-send-email-okaya@codeaurora.org> (raw)
In-Reply-To: <1521514207-10695-1-git-send-email-okaya@codeaurora.org>

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 writel() to
writel_relaxed().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/scsi/dpt_i2o.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/dpt_i2o.c b/drivers/scsi/dpt_i2o.c
index fd172b0..3c1e64a 100644
--- a/drivers/scsi/dpt_i2o.c
+++ b/drivers/scsi/dpt_i2o.c
@@ -1300,7 +1300,7 @@ static s32 adpt_i2o_post_this(adpt_hba* pHba, u32* data, int len)
 	wmb();
 
 	//post message
-	writel(m, pHba->post_port);
+	writel_relaxed(m, pHba->post_port);
 	wmb();
 
 	return 0;
@@ -1390,7 +1390,7 @@ static s32 adpt_i2o_reset_hba(adpt_hba* pHba)
 
 	memcpy_toio(pHba->msg_addr_virt+m, msg, sizeof(msg));
 	wmb();
-	writel(m, pHba->post_port);
+	writel_relaxed(m, pHba->post_port);
 	wmb();
 
 	while(*status == 0){
@@ -2797,7 +2797,7 @@ static s32 adpt_send_nop(adpt_hba*pHba,u32 m)
 	writel( 0,&msg[2]);
 	wmb();
 
-	writel(m, pHba->post_port);
+	writel_relaxed(m, pHba->post_port);
 	wmb();
 	return 0;
 }
-- 
2.7.4

  parent reply	other threads:[~2018-03-20  2:52 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1521514207-10695-1-git-send-email-okaya@codeaurora.org>
2018-03-20  2:50 ` [PATCH v4 1/7] scsi: hpsa: Eliminate " Sinan Kaya
2018-03-20 16:51   ` Laurence Oberman
2018-03-20  2:50 ` [PATCH v4 2/7] scsi: megaraid: eliminate " Sinan Kaya
2018-03-20  2:50 ` Sinan Kaya [this message]
2018-03-20 10:23   ` [PATCH v4 3/7] scsi: dpt_i2o: " Christoph Hellwig
2018-03-20 12:13     ` okaya
2018-03-20  2:50 ` [PATCH v4 4/7] scsi: lpfc: Eliminate " Sinan Kaya
2018-03-20  2:50 ` [PATCH v4 5/7] scsi: ipr: " Sinan Kaya
2018-05-29 20:45   ` Brian King
2018-03-20  2:50 ` [PATCH v4 6/7] scsi: bnx2i: " Sinan Kaya
2018-03-20  2:50 ` [PATCH v4 7/7] scsi: csiostor: " Sinan Kaya

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1521514207-10695-4-git-send-email-okaya@codeaurora.org \
    --to=okaya@codeaurora.org \
    --cc=aacraid@adaptec.com \
    --cc=jejb@linux.vnet.ibm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=martin.petersen@oracle.com \
    --cc=sulrich@codeaurora.org \
    --cc=timur@codeaurora.org \
    --subject='Re: [PATCH v4 3/7] scsi: dpt_i2o: eliminate duplicate barriers on weakly-ordered archs' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).