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From:   Yury Norov <yury.norov@gmail.com>
To:     linux-kernel@vger.kernel.org,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        Rob Herring <robh@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org
Cc:     Yury Norov <yury.norov@gmail.com>, Jan Kara <jack@suse.cz>,
        Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>,
        Matthew Wilcox <willy@infradead.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org>,
        Alexey Klimov <klimov.linux@gmail.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Sergey Shtylyov <s.shtylyov@omp.ru>,
        Michael Kelley <mhklinux@outlook.com>
Subject: [PATCH v3 14/35] PCI: hv: Optimize hv_get_dom_num() by using find_and_set_bit()
Date:   Mon, 11 Dec 2023 18:27:28 -0800
Message-Id: <20231212022749.625238-15-yury.norov@gmail.com>
In-Reply-To: <20231212022749.625238-1-yury.norov@gmail.com>
References: <20231212022749.625238-1-yury.norov@gmail.com>
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The function traverses bitmap with for_each_clear_bit() just to allocate
a bit atomically. Simplify it by using dedicated find_and_set_bit().

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.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