[PATCH 2/2] RDMA/pvrdma: Use non-atomic bitmap functions when possible

Christophe JAILLET
2021-11-25T20:07:55Z

In 'pvrdma_uar_table_init()', the 'tbl->table' bitmap has just been
allocated, so no concurrent accesses can occur.

The other accesses to the 'tbl->table' bitmap are protected by the
'tbl->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/vmw_pvrdma/pvrdma_doorbell.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/hw/vmw_pvrdma/pvrdma_doorbell.c b/drivers/infiniband/hw/vmw_pvrdma/pvrdma_doorbell.c
index 21ef3fb39915..9a4de962e947 100644
--- a/drivers/infiniband/hw/vmw_pvrdma/pvrdma_doorbell.c
+++ b/drivers/infiniband/hw/vmw_pvrdma/pvrdma_doorbell.c
@@ -68,7 +68,7 @@ int pvrdma_uar_table_init(struct pvrdma_dev *dev)
return -ENOMEM;

/* 0th UAR is taken by the device. */
- set_bit(0, tbl->table);
+ __set_bit(0, tbl->table);

return 0;
}
@@ -100,7 +100,7 @@ int pvrdma_uar_alloc(struct pvrdma_dev *dev, struct pvrdma_uar_map *uar)
return -ENOMEM;
}

- set_bit(obj, tbl->table);
+ __set_bit(obj, tbl->table);
obj |= tbl->top;

spin_unlock_irqrestore(&tbl->lock, flags);
@@ -120,7 +120,7 @@ void pvrdma_uar_free(struct pvrdma_dev *dev, struct pvrdma_uar_map *uar)

obj = uar->index & (tbl->max - 1);
spin_lock_irqsave(&tbl->lock, flags);
- clear_bit(obj, tbl->table);
+ __clear_bit(obj, tbl->table);
tbl->last = min(tbl->last, obj);
tbl->top = (tbl->top + tbl->max) & tbl->mask;
spin_unlock_irqrestore(&tbl->lock, flags);
--
2.30.2