linux-kernel - [PATCH 3/4] IB/mthca: Use non-atomic bitmap functions when possible in 'mthca

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Message-Id: <5f909ca1284fa4d2cf13952b08b9e303b656c968.1637785902.git.christophe.jaillet@wanadoo.fr>
Date:   Wed, 24 Nov 2021 21:42:32 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     dledford@...hat.com, jgg@...pe.ca
Cc:     linux-rdma@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH 3/4] IB/mthca: Use non-atomic bitmap functions when possible in 'mthca_allocator.c'

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@...adoo.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