LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: "Ruhl, Michael J" <michael.j.ruhl@intel.com>
To: Andrea Parri <andrea.parri@amarulasolutions.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "stable@vger.kernel.org" <stable@vger.kernel.org>,
	"Dalessandro, Dennis" <dennis.dalessandro@intel.com>,
	"Marciniszyn, Mike" <mike.marciniszyn@intel.com>,
	Doug Ledford <dledford@redhat.com>,
	"Jason Gunthorpe" <jgg@ziepe.ca>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: RE: [PATCH 5/5] IB/hfi1: Fix improper uses of smp_mb__before_atomic()
Date: Mon, 29 Apr 2019 21:24:24 +0000	[thread overview]
Message-ID: <14063C7AD467DE4B82DEDB5C278E8663BE6AADCE@FMSMSX108.amr.corp.intel.com> (raw)
In-Reply-To: <1556568902-12464-6-git-send-email-andrea.parri@amarulasolutions.com>

>-----Original Message-----
>From: linux-rdma-owner@vger.kernel.org [mailto:linux-rdma-
>owner@vger.kernel.org] On Behalf Of Andrea Parri
>Sent: Monday, April 29, 2019 4:15 PM
>To: linux-kernel@vger.kernel.org
>Cc: Andrea Parri <andrea.parri@amarulasolutions.com>;
>stable@vger.kernel.org; Dalessandro, Dennis
><dennis.dalessandro@intel.com>; Marciniszyn, Mike
><mike.marciniszyn@intel.com>; Doug Ledford <dledford@redhat.com>;
>Jason Gunthorpe <jgg@ziepe.ca>; linux-rdma@vger.kernel.org
>Subject: [PATCH 5/5] IB/hfi1: Fix improper uses of smp_mb__before_atomic()
>
>This barrier only applies to the read-modify-write operations; in
>particular, it does not apply to the atomic_read() primitive.
>
>Replace the barrier with an smp_mb().

This is one of a couple of barrier issues that we are currently looking into.

See:

[PATCH for-next 6/9] IB/rdmavt: Add new completion inline

We will take a look at this one as well.

Thanks,

Mike

>Fixes: 856cc4c237add ("IB/hfi1: Add the capability for reserved operations")
>Cc: stable@vger.kernel.org
>Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com>
>Reported-by: Peter Zijlstra <peterz@infradead.org>
>Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
>Cc: Dennis Dalessandro <dennis.dalessandro@intel.com>
>Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
>Cc: Doug Ledford <dledford@redhat.com>
>Cc: Jason Gunthorpe <jgg@ziepe.ca>
>Cc: linux-rdma@vger.kernel.org
>---
> drivers/infiniband/sw/rdmavt/qp.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
>diff --git a/drivers/infiniband/sw/rdmavt/qp.c
>b/drivers/infiniband/sw/rdmavt/qp.c
>index a34b9a2a32b60..b64fd151d31fb 100644
>--- a/drivers/infiniband/sw/rdmavt/qp.c
>+++ b/drivers/infiniband/sw/rdmavt/qp.c
>@@ -1863,11 +1863,11 @@ static inline int rvt_qp_is_avail(
> 	u32 reserved_used;
>
> 	/* see rvt_qp_wqe_unreserve() */
>-	smp_mb__before_atomic();
>+	smp_mb();
> 	reserved_used = atomic_read(&qp->s_reserved_used);
> 	if (unlikely(reserved_op)) {
> 		/* see rvt_qp_wqe_unreserve() */
>-		smp_mb__before_atomic();
>+		smp_mb();
> 		if (reserved_used >= rdi->dparms.reserved_operations)
> 			return -ENOMEM;
> 		return 0;
>@@ -1882,7 +1882,7 @@ static inline int rvt_qp_is_avail(
> 		avail = slast - qp->s_head;
>
> 	/* see rvt_qp_wqe_unreserve() */
>-	smp_mb__before_atomic();
>+	smp_mb();
> 	reserved_used = atomic_read(&qp->s_reserved_used);
> 	avail =  avail - 1 -
> 		(rdi->dparms.reserved_operations - reserved_used);
>--
>2.7.4


  reply	other threads:[~2019-04-29 21:24 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-29 20:14 [PATCH 0/5] Fix improper uses of smp_mb__{before,after}_atomic() Andrea Parri
2019-04-29 20:14 ` [PATCH 1/5] drm/msm: " Andrea Parri
2019-05-09 20:19   ` Andrea Parri
2019-04-29 20:14 ` [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() Andrea Parri
2019-04-30  8:21   ` Peter Zijlstra
2019-05-09 20:23   ` Andrea Parri
2019-05-10  3:40   ` Ming Lei
2019-04-29 20:14 ` [PATCH 3/5] sbitmap: " Andrea Parri
2019-05-09 20:26   ` Andrea Parri
2019-05-10  3:41   ` Ming Lei
2019-05-10  6:27     ` Andrea Parri
2019-04-29 20:15 ` [PATCH 4/5] ceph: " Andrea Parri
2019-04-30  8:23   ` Peter Zijlstra
2019-04-30  9:08     ` Yan, Zheng
2019-05-09 20:55       ` Andrea Parri
2019-05-13 13:04         ` Yan, Zheng
2019-05-13 22:47           ` Andrea Parri
2019-04-29 20:15 ` [PATCH 5/5] IB/hfi1: Fix improper uses " Andrea Parri
2019-04-29 21:24   ` Ruhl, Michael J [this message]
2019-04-29 23:16     ` Andrea Parri
2019-05-09 21:12       ` Andrea Parri
2019-05-14 12:32         ` Dennis Dalessandro
2019-05-14 14:48           ` Andrea Parri
2019-04-30  8:28   ` Peter Zijlstra
2019-04-30  8:34 ` [PATCH 0/5] Fix improper uses of smp_mb__{before,after}_atomic() Peter Zijlstra
2019-04-30 16:44   ` Andrea Parri

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=14063C7AD467DE4B82DEDB5C278E8663BE6AADCE@FMSMSX108.amr.corp.intel.com \
    --to=michael.j.ruhl@intel.com \
    --cc=andrea.parri@amarulasolutions.com \
    --cc=dennis.dalessandro@intel.com \
    --cc=dledford@redhat.com \
    --cc=jgg@ziepe.ca \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=mike.marciniszyn@intel.com \
    --cc=stable@vger.kernel.org \
    --subject='RE: [PATCH 5/5] IB/hfi1: Fix improper uses of smp_mb__before_atomic()' \
    /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).