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From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: dledford@redhat.com, jgg@ziepe.ca
Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org,
	Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Subject: [PATCH 3/4] IB/mthca: Use non-atomic bitmap functions when possible in 'mthca_allocator.c'
Date: Wed, 24 Nov 2021 21:42:32 +0100	[thread overview]
Message-ID: <5f909ca1284fa4d2cf13952b08b9e303b656c968.1637785902.git.christophe.jaillet@wanadoo.fr> (raw)
In-Reply-To: <cover.1637785902.git.christophe.jaillet@wanadoo.fr>

The accesses to the 'alloc->table' bitmap are protected by the
'alloc->lock' spinlock, so no concurrent accesses can happen.

So prefer the non-atomic '__[set|clear]_bit()' functions to save a few
cycles.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/infiniband/hw/mthca/mthca_allocator.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mthca/mthca_allocator.c b/drivers/infiniband/hw/mthca/mthca_allocator.c
index 57fa1cc202bc..9f0f79d02d3c 100644
--- a/drivers/infiniband/hw/mthca/mthca_allocator.c
+++ b/drivers/infiniband/hw/mthca/mthca_allocator.c
@@ -51,7 +51,7 @@ u32 mthca_alloc(struct mthca_alloc *alloc)
 	}
 
 	if (obj < alloc->max) {
-		set_bit(obj, alloc->table);
+		__set_bit(obj, alloc->table);
 		obj |= alloc->top;
 	} else
 		obj = -1;
@@ -69,7 +69,7 @@ void mthca_free(struct mthca_alloc *alloc, u32 obj)
 
 	spin_lock_irqsave(&alloc->lock, flags);
 
-	clear_bit(obj, alloc->table);
+	__clear_bit(obj, alloc->table);
 	alloc->last = min(alloc->last, obj);
 	alloc->top = (alloc->top + alloc->max) & alloc->mask;
 
-- 
2.30.2


  parent reply	other threads:[~2021-11-24 20:43 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-24 20:40 [PATCH 0/4] IB/mthca: Cleanup and optimize a few bitmap operation Christophe JAILLET
2021-11-24 20:40 ` [PATCH 1/4] IB/mthca: Use bitmap_zalloc() when applicable Christophe JAILLET
2021-11-24 20:41 ` [PATCH 2/4] IB/mthca: Use bitmap_set() " Christophe JAILLET
2021-11-24 20:42 ` Christophe JAILLET [this message]
2021-11-24 20:43 ` [PATCH 4/4] IB/mthca: Use non-atomic bitmap functions when possible in 'mthca_mr.c' Christophe JAILLET
2021-11-25 17:30 ` [PATCH 0/4] IB/mthca: Cleanup and optimize a few bitmap operation Jason Gunthorpe

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