[PATCH 4/4] IB/mthca: Use non-atomic bitmap functions when possible in 'mthca_mr.c'

From: Christophe JAILLET
Date: Wed Nov 24 2021 - 15:44:15 EST


In 'mthca_buddy_init()', the 'buddy->bits[n]' bitmap has just been
allocated, so no concurrent accesses can occur.

The other accesses to the 'buddy->bits[n]' bitmap are protected by the
'buddy->lock' spinlock, so no concurrent accesses can occur.

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

Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
---
drivers/infiniband/hw/mthca/mthca_mr.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/hw/mthca/mthca_mr.c b/drivers/infiniband/hw/mthca/mthca_mr.c
index 8892fcdbac4c..a59100c496b4 100644
--- a/drivers/infiniband/hw/mthca/mthca_mr.c
+++ b/drivers/infiniband/hw/mthca/mthca_mr.c
@@ -101,13 +101,13 @@ static u32 mthca_buddy_alloc(struct mthca_buddy *buddy, int order)
return -1;

found:
- clear_bit(seg, buddy->bits[o]);
+ __clear_bit(seg, buddy->bits[o]);
--buddy->num_free[o];

while (o > order) {
--o;
seg <<= 1;
- set_bit(seg ^ 1, buddy->bits[o]);
+ __set_bit(seg ^ 1, buddy->bits[o]);
++buddy->num_free[o];
}

@@ -125,13 +125,13 @@ static void mthca_buddy_free(struct mthca_buddy *buddy, u32 seg, int order)
spin_lock(&buddy->lock);

while (test_bit(seg ^ 1, buddy->bits[order])) {
- clear_bit(seg ^ 1, buddy->bits[order]);
+ __clear_bit(seg ^ 1, buddy->bits[order]);
--buddy->num_free[order];
seg >>= 1;
++order;
}

- set_bit(seg, buddy->bits[order]);
+ __set_bit(seg, buddy->bits[order]);
++buddy->num_free[order];

spin_unlock(&buddy->lock);
@@ -158,7 +158,7 @@ static int mthca_buddy_init(struct mthca_buddy *buddy, int max_order)
goto err_out_free;
}

- set_bit(0, buddy->bits[buddy->max_order]);
+ __set_bit(0, buddy->bits[buddy->max_order]);
buddy->num_free[buddy->max_order] = 1;

return 0;
--
2.30.2