From: Jijie Shao
Sent: 28 July 2023 08:59
num_online_cpus() may call more than once when passing to min_t(), between calls, it may return different values, so move num_online_cpus() out of min_t().
Nope, wrong bug: min() (and friends) are careful to only evaluate their arguments once. The bug is using min_t() - especially with a small type.
If/when the number of cpu hits 65536 the (u16) cast will convert it to zero.
Looking at the code a lot of the local variables should be 'unsigned int' not 'u16. Just because the domain of a value is small doesn't mean you should use a small type (unless you are saving space in a structure).
David
Signed-off-by: Yonglong Liu liuyonglong@huawei.com Signed-off-by: Jijie Shao shaojijie@huawei.com
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c index 9f6890059666..823e6d2e85f5 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c @@ -4757,6 +4757,7 @@ static int hns3_nic_alloc_vector_data(struct hns3_nic_priv *priv) { struct hnae3_handle *h = priv->ae_handle; struct hns3_enet_tqp_vector *tqp_vector;
- u32 online_cpus = num_online_cpus(); struct hnae3_vector_info *vector; struct pci_dev *pdev = h->pdev; u16 tqp_num = h->kinfo.num_tqps;
@@ -4766,7 +4767,7 @@ static int hns3_nic_alloc_vector_data(struct hns3_nic_priv *priv)
/* RSS size, cpu online and vector_num should be the same */ /* Should consider 2p/4p later */
- vector_num = min_t(u16, num_online_cpus(), tqp_num);
vector_num = min_t(u16, online_cpus, tqp_num);
vector = devm_kcalloc(&pdev->dev, vector_num, sizeof(*vector), GFP_KERNEL);
-- 2.30.0
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