2024-04-30 22:48:01

by Jules Irenge

Subject: [PATCH v2] RDMA/core: Remove NULL check before dev_{put, hold}

Coccinelle reports a warning

WARNING: NULL check before dev_{put, hold} functions is not needed

The reason is the call netdev_{put, hold} of dev_{put,hold} will check NULL
There is no need to check before using dev_{put, hold}

Signed-off-by: Jules Irenge <[email protected]>
---
Changes in v2:
- Merge two previous patches into one as directed

drivers/infiniband/core/device.c | 10 +++-------
drivers/infiniband/core/lag.c | 3 +--
drivers/infiniband/core/roce_gid_mgmt.c | 3 +--
3 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 07cb6c5ffda0..55aa7aa32d4a 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -2174,8 +2174,7 @@ int ib_device_set_netdev(struct ib_device *ib_dev, struct net_device *ndev,
spin_unlock_irqrestore(&pdata->netdev_lock, flags);

add_ndev_hash(pdata);
- if (old_ndev)
- __dev_put(old_ndev);
+ __dev_put(old_ndev);

return 0;
}
@@ -2235,8 +2234,7 @@ struct net_device *ib_device_get_netdev(struct ib_device *ib_dev,
spin_lock(&pdata->netdev_lock);
res = rcu_dereference_protected(
pdata->netdev, lockdep_is_held(&pdata->netdev_lock));
- if (res)
- dev_hold(res);
+ dev_hold(res);
spin_unlock(&pdata->netdev_lock);
}

@@ -2311,9 +2309,7 @@ void ib_enum_roce_netdev(struct ib_device *ib_dev,

if (filter(ib_dev, port, idev, filter_cookie))
cb(ib_dev, port, idev, cookie);
-
- if (idev)
- dev_put(idev);
+ dev_put(idev);
}
}

diff --git a/drivers/infiniband/core/lag.c b/drivers/infiniband/core/lag.c
index eca6e37c72ba..8fd80adfe833 100644
--- a/drivers/infiniband/core/lag.c
+++ b/drivers/infiniband/core/lag.c
@@ -93,8 +93,7 @@ static struct net_device *rdma_get_xmit_slave_udp(struct ib_device *device,
slave = netdev_get_xmit_slave(master, skb,
!!(device->lag_flags &
RDMA_LAG_FLAGS_HASH_ALL_SLAVES));
- if (slave)
- dev_hold(slave);
+ dev_hold(slave);
rcu_read_unlock();
kfree_skb(skb);
return slave;
diff --git a/drivers/infiniband/core/roce_gid_mgmt.c b/drivers/infiniband/core/roce_gid_mgmt.c
index e958c43dd28f..d5131b3ba8ab 100644
--- a/drivers/infiniband/core/roce_gid_mgmt.c
+++ b/drivers/infiniband/core/roce_gid_mgmt.c
@@ -601,8 +601,7 @@ static void del_netdev_default_ips_join(struct ib_device *ib_dev, u32 port,

rcu_read_lock();
master_ndev = netdev_master_upper_dev_get_rcu(rdma_ndev);
- if (master_ndev)
- dev_hold(master_ndev);
+ dev_hold(master_ndev);
rcu_read_unlock();

if (master_ndev) {
--
2.43.2

2024-05-02 06:29:18

by Markus Elfring

Subject: Re: [PATCH v2] RDMA/core: Remove NULL check before dev_{put, hold}

…
> There is no need to check before using dev_{put, hold}

How do you think about to improve the change description with a corresponding imperative wording?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.9-rc6#n94

Regards,
Markus

2024-05-05 12:13:55

by Leon Romanovsky

Subject: Re: [PATCH v2] RDMA/core: Remove NULL check before dev_{put, hold}

On Tue, 30 Apr 2024 23:47:45 +0100, Jules Irenge wrote:
> Coccinelle reports a warning
>
> WARNING: NULL check before dev_{put, hold} functions is not needed
>
> The reason is the call netdev_{put, hold} of dev_{put,hold} will check NULL
> There is no need to check before using dev_{put, hold}
>
> [...]

Applied, thanks!

[1/1] RDMA/core: Remove NULL check before dev_{put, hold}
https://git.kernel.org/rdma/rdma/c/48d80b484491f1

Best regards,
--
Leon Romanovsky <[email protected]>