[PATCH 1/2] usnic: add rtnl lock around __ethtool_get_link_ksettings()

[PATCH 1/2] usnic: add rtnl lock around __ethtool_get_link_ksettings()

[Govindarajulu Varadarajan]

__ethtool_get_link_ksettings requires rtnl lock. If not it throws the
following warnning.

[ 1855.996191] RTNL: assertion failed at net/core/ethtool.c (564)
[ 1855.997084] CPU: 12 PID: 1866 Comm: kworker/12:0 Not tainted 4.12.0+ #47
[ 1855.997982] Hardware name: Cisco Systems Inc UCSC-C240-M4S2/UCSC-C240-M4S2, BIOS C240M4.2.0.12.503.0307172239 03/07/2017
[ 1855.998949] Workqueue: infiniband ib_cache_task [ib_core]
[ 1855.999920] Call Trace:
[ 1856.000872]  dump_stack+0x63/0x8b
[ 1856.001576] enic 0000:11:00.0 a0: Link DOWN
[ 1856.002769]  __ethtool_get_link_ksettings+0xfe/0x110
[ 1856.003733]  ? netlink_broadcast_filtered+0x14b/0x3a0
[ 1856.004703]  usnic_ib_query_port+0x46/0x1c0 [usnic_verbs]
[ 1856.005680]  ib_query_port+0x9e/0x120 [ib_core]
[ 1856.006654]  ib_cache_update+0xcf/0x430 [ib_core]
[ 1856.007621]  ? ib_cache_update+0xcf/0x430 [ib_core]
[ 1856.008601]  ? netdev_run_todo+0x51/0x2f0
[ 1856.009581]  ? linkwatch_do_dev+0x38/0x50
[ 1856.010588]  ib_cache_task+0x1e/0x30 [ib_core]
[ 1856.011564]  process_one_work+0x1bc/0x3e0
[ 1856.012528]  worker_thread+0x4a/0x3a0
[ 1856.013486]  kthread+0x125/0x140
[ 1856.014437]  ? process_one_work+0x3e0/0x3e0
[ 1856.015378]  ? kthread_create_on_node+0x40/0x40
[ 1856.016318]  ret_from_fork+0x25/0x30

Signed-off-by: Govindarajulu Varadarajan <gvaradar-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
---
 drivers/infiniband/hw/usnic/usnic_ib_verbs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/usnic/usnic_ib_verbs.c b/drivers/infiniband/hw/usnic/usnic_ib_verbs.c
index 4996984885c2..03002bac93e7 100644
--- a/drivers/infiniband/hw/usnic/usnic_ib_verbs.c
+++ b/drivers/infiniband/hw/usnic/usnic_ib_verbs.c
@@ -331,7 +331,9 @@ int usnic_ib_query_port(struct ib_device *ibdev, u8 port,
 	usnic_dbg("\n");
 
 	mutex_lock(&us_ibdev->usdev_lock);
+	rtnl_lock();
 	__ethtool_get_link_ksettings(us_ibdev->netdev, &cmd);
+	rtnl_unlock();
 	/* props being zeroed by the caller, avoid zeroing it here */
 
 	props->lid = 0;
-- 
2.13.2

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[PATCH 2/2] usnic: do not ignore return value of __ethtool_get_link_ksettings

[Govindarajulu Varadarajan]

Do not ignore the return value of the caller.

Signed-off-by: Govindarajulu Varadarajan <gvaradar-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
---
 drivers/infiniband/hw/usnic/usnic_ib_verbs.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/usnic/usnic_ib_verbs.c b/drivers/infiniband/hw/usnic/usnic_ib_verbs.c
index 03002bac93e7..c0b82a990bc9 100644
--- a/drivers/infiniband/hw/usnic/usnic_ib_verbs.c
+++ b/drivers/infiniband/hw/usnic/usnic_ib_verbs.c
@@ -327,13 +327,16 @@ int usnic_ib_query_port(struct ib_device *ibdev, u8 port,
 {
 	struct usnic_ib_dev *us_ibdev = to_usdev(ibdev);
 	struct ethtool_link_ksettings cmd;
+	int err = 0;
 
 	usnic_dbg("\n");
 
 	mutex_lock(&us_ibdev->usdev_lock);
 	rtnl_lock();
-	__ethtool_get_link_ksettings(us_ibdev->netdev, &cmd);
+	err = __ethtool_get_link_ksettings(us_ibdev->netdev, &cmd);
 	rtnl_unlock();
+	if (err)
+		goto out;
 	/* props being zeroed by the caller, avoid zeroing it here */
 
 	props->lid = 0;
@@ -364,9 +367,10 @@ int usnic_ib_query_port(struct ib_device *ibdev, u8 port,
 	/* Userspace will adjust for hdrs */
 	props->max_msg_sz = us_ibdev->ufdev->mtu;
 	props->max_vl_num = 1;
+out:
 	mutex_unlock(&us_ibdev->usdev_lock);
 
-	return 0;
+	return err;
 }
 
 int usnic_ib_query_qp(struct ib_qp *qp, struct ib_qp_attr *qp_attr,
-- 
2.13.2

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Re: [PATCH 2/2] usnic: do not ignore return value of __ethtool_get_link_ksettings

[Leon Romanovsky]

[-- Attachment #1: Type: text/plain, Size: 1839 bytes --]

On Thu, Jul 13, 2017 at 03:46:25PM -0700, Govindarajulu Varadarajan wrote:
> Do not ignore the return value of the caller.
>
> Signed-off-by: Govindarajulu Varadarajan <gvaradar-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/infiniband/hw/usnic/usnic_ib_verbs.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/infiniband/hw/usnic/usnic_ib_verbs.c b/drivers/infiniband/hw/usnic/usnic_ib_verbs.c
> index 03002bac93e7..c0b82a990bc9 100644
> --- a/drivers/infiniband/hw/usnic/usnic_ib_verbs.c
> +++ b/drivers/infiniband/hw/usnic/usnic_ib_verbs.c
> @@ -327,13 +327,16 @@ int usnic_ib_query_port(struct ib_device *ibdev, u8 port,
>  {
>  	struct usnic_ib_dev *us_ibdev = to_usdev(ibdev);
>  	struct ethtool_link_ksettings cmd;
> +	int err = 0;

Please don't assign variable which will be overwritten immediately.
It has potential to hide the errors.

Thanks

>
>  	usnic_dbg("\n");
>
>  	mutex_lock(&us_ibdev->usdev_lock);
>  	rtnl_lock();
> -	__ethtool_get_link_ksettings(us_ibdev->netdev, &cmd);
> +	err = __ethtool_get_link_ksettings(us_ibdev->netdev, &cmd);
>  	rtnl_unlock();
> +	if (err)
> +		goto out;
>  	/* props being zeroed by the caller, avoid zeroing it here */
>
>  	props->lid = 0;
> @@ -364,9 +367,10 @@ int usnic_ib_query_port(struct ib_device *ibdev, u8 port,
>  	/* Userspace will adjust for hdrs */
>  	props->max_msg_sz = us_ibdev->ufdev->mtu;
>  	props->max_vl_num = 1;
> +out:
>  	mutex_unlock(&us_ibdev->usdev_lock);
>
> -	return 0;
> +	return err;
>  }
>
>  int usnic_ib_query_qp(struct ib_qp *qp, struct ib_qp_attr *qp_attr,
> --
> 2.13.2
>
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