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SubjectRE: [PATCH 14/34] PCI: hv: switch hv_get_dom_num() to use atomic find_bit()
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From: Yury Norov <yury.norov@gmail.com> Sent: Saturday, November 18, 2023 7:51 AM
>
> 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>
> ---
> 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;
> }
>
> /**
> --
> 2.39.2

Reviewed-by: Michael Kelley <mhklinux@outlook.com>

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