[PATCH v2 14/35] PCI: hv: switch hv_get_dom_num() to use atomic find_bit()

Yury Norov
2023-12-03T19:33:36Z

The function traverses bitmap with for_each_clear_bit() just to allocate
a bit atomically. We can do it better with a dedicated find_and_set_bit().

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
---
drivers/pci/controller/pci-hyperv.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 30c7dfeccb16..033b1fb7f4eb 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -3605,12 +3605,9 @@ static u16 hv_get_dom_num(u16 dom)
if (test_and_set_bit(dom, hvpci_dom_map) == 0)
return dom;

- for_each_clear_bit(i, hvpci_dom_map, HVPCI_DOM_MAP_SIZE) {
- if (test_and_set_bit(i, hvpci_dom_map) == 0)
- return i;
- }
+ i = find_and_set_bit(hvpci_dom_map, HVPCI_DOM_MAP_SIZE);

- return HVPCI_DOM_INVALID;
+ return i < HVPCI_DOM_MAP_SIZE ? i : HVPCI_DOM_INVALID;
}

/**
--
2.40.1