linux-kernel - [PATCH 08/12] infiniband: Employ atomic_fetch

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Date:	Mon, 20 Jun 2016 13:06:00 -0700
From:	Davidlohr Bueso <dave@...olabs.net>
To:	peterz@...radead.org, mingo@...nel.org
Cc:	davem@...emloft.net, cw00.choi@...sung.com,
	dougthompson@...ssion.com, bp@...en8.de, mchehab@....samsung.com,
	gregkh@...uxfoundation.org, pfg@....com, jikos@...nel.org,
	hans.verkuil@...co.com, awalls@...metrocast.net,
	dledford@...hat.com, sean.hefty@...el.com, kys@...rosoft.com,
	heiko.carstens@...ibm.com, James.Bottomley@...senPartnership.com,
	sumit.semwal@...aro.org, schwidefsky@...ibm.com,
	linux-kernel@...r.kernel.org, dave@...olabs.net,
	Hal Rosenstock <hal.rosenstock@...il.com>,
	Davidlohr Bueso <dbueso@...e.de>
Subject: [PATCH 08/12] infiniband: Employ atomic_fetch_inc()

Now that we have fetch_inc() we can stop using inc_return() - 1.

These are very similar to the existing OP-RETURN primitives we already
have, except they return the value of the atomic variable _before_
modification.

Cc: Doug Ledford <dledford@...hat.com>
Cc: Sean Hefty <sean.hefty@...el.com>
Cc: Hal Rosenstock <hal.rosenstock@...il.com>
Signed-off-by: Davidlohr Bueso <dbueso@...e.de>
---
 drivers/infiniband/hw/cxgb4/device.c | 3 +--
 drivers/infiniband/hw/hfi1/verbs.c   | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/hw/cxgb4/device.c b/drivers/infiniband/hw/cxgb4/device.c
index ae2e8b23d2dd..a32959fa2c82 100644
--- a/drivers/infiniband/hw/cxgb4/device.c
+++ b/drivers/infiniband/hw/cxgb4/device.c
@@ -111,8 +111,7 @@ void c4iw_log_wr_stats(struct t4_wq *wq, struct t4_cqe *cqe)
 	if (!wq->rdev->wr_log)
 		return;
 
-	idx = (atomic_inc_return(&wq->rdev->wr_log_idx) - 1) &
-		(wq->rdev->wr_log_size - 1);
+	idx = atomic_fetch_inc(&wq->rdev->wr_log_idx) & (wq->rdev->wr_log_size - 1);
 	le.poll_sge_ts = cxgb4_read_sge_timestamp(wq->rdev->lldi.ports[0]);
 	getnstimeofday(&le.poll_host_ts);
 	le.valid = 1;
diff --git a/drivers/infiniband/hw/hfi1/verbs.c b/drivers/infiniband/hw/hfi1/verbs.c
index 849c4b9399d4..9ba311b53085 100644
--- a/drivers/infiniband/hw/hfi1/verbs.c
+++ b/drivers/infiniband/hw/hfi1/verbs.c
@@ -261,8 +261,7 @@ static void wss_advance_clean_counter(void)
 		 * wss.clean_entry.  The table size, wss.num_entries,
 		 * is always a power-of-2.
 		 */
-		entry = (atomic_inc_return(&wss.clean_entry) - 1)
-			& (wss.num_entries - 1);
+		entry = atomic_fetch_inc(&wss.clean_entry) & (wss.num_entries - 1);
 
 		/* clear the entry and count the bits */
 		bits = xchg(&wss.entries[entry], 0);
-- 
2.6.6