linux-kernel - [PATCH 2/2] Drivers: hv: Compare cpumasks and not their weights in init_vp

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Date:   Fri, 28 Jan 2022 11:34:12 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     linux-hyperv@...r.kernel.org, Wei Liu <wei.liu@...nel.org>
Cc:     linux-kernel@...r.kernel.org,
        Michael Kelley <mikelley@...rosoft.com>,
        "K. Y. Srinivasan" <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Dexuan Cui <decui@...rosoft.com>
Subject: [PATCH 2/2] Drivers: hv: Compare cpumasks and not their weights in init_vp_index()

The condition is supposed to check whether 'allocated_mask' got fully
exhausted, i.e. there's no free CPU on the NUMA node left so we have
to use one of the already used CPUs. As only bits which correspond
to CPUs from 'cpumask_of_node(numa_node)' get set in 'allocated_mask',
checking for the equal weights is technically correct but not obvious.
Let's compare cpumasks directly.

No functional change intended.

Suggested-by: Michael Kelley <mikelley@...rosoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 drivers/hv/channel_mgmt.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 52cf6ae525e9..26d269ba947c 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -762,8 +762,7 @@ static void init_vp_index(struct vmbus_channel *channel)
 		}
 		allocated_mask = &hv_context.hv_numa_map[numa_node];
 
-		if (cpumask_weight(allocated_mask) ==
-		    cpumask_weight(cpumask_of_node(numa_node))) {
+		if (cpumask_equal(allocated_mask, cpumask_of_node(numa_node))) {
 			/*
 			 * We have cycled through all the CPUs in the node;
 			 * reset the allocated map.
-- 
2.34.1