2024-01-15 07:57:51

by Yin, Fengwei

Subject: Re: [PATCH] connector: Change the judgment conditions for clearing proc_event_num_listeners

On 1/15/2024 3:51 PM, wangkeqi wrote:
> From: wangkeqi <[email protected]>
>
> It is inaccurate to judge whether proc_event_num_listeners is
> cleared by cn_netlink_send_mult returning -ESRCH.
> In the case of stress-ng netlink-proc, -ESRCH will always be returned,
> because netlink_broadcast_filtered will return -ESRCH,
> which may cause stress-ng netlink-proc performance degradation.
> Therefore, the judgment condition is modified to whether
> there is a listener.
>
> Signed-off-by: wangkeqi <[email protected]>

Regarding the original report:

If you fix the issue in a separate patch/commit (i.e. not just a new
version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes:
https://lore.kernel.org/oe-lkp/[email protected]


Could you please add the tag? Thanks.

> ---
> drivers/connector/cn_proc.c | 6 ++++--
> drivers/connector/connector.c | 6 ++++++
> include/linux/connector.h | 1 +
> 3 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
> index 3d5e6d705..b09f74ed3 100644
> --- a/drivers/connector/cn_proc.c
> +++ b/drivers/connector/cn_proc.c
> @@ -108,8 +108,10 @@ static inline void send_msg(struct cn_msg *msg)
> filter_data[1] = 0;
> }
>
> - if (cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
> - cn_filter, (void *)filter_data) == -ESRCH)
> + if (netlink_has_listeners(get_cdev_nls(), CN_IDX_PROC))
> + cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
> + cn_filter, (void *)filter_data);
> + else
> atomic_set(&proc_event_num_listeners, 0);
>
> local_unlock(&local_event.lock);
> diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
> index 7f7b94f61..1b2cd410e 100644
> --- a/drivers/connector/connector.c
> +++ b/drivers/connector/connector.c
> @@ -129,6 +129,12 @@ int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 __group,
> }
> EXPORT_SYMBOL_GPL(cn_netlink_send);
>
> +struct sock *get_cdev_nls(void)
> +{
> + return cdev.nls;
> +}
> +EXPORT_SYMBOL_GPL(get_cdev_nls);
> +
> /*
> * Callback helper - queues work and setup destructor for given data.
> */
> diff --git a/include/linux/connector.h b/include/linux/connector.h
> index cec2d99ae..255466aea 100644
> --- a/include/linux/connector.h
> +++ b/include/linux/connector.h
> @@ -127,6 +127,7 @@ int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid,
> */
> int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_mask);
>
> +struct sock *get_cdev_nls(void);
> int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
> const struct cb_id *id,
> void (*callback)(struct cn_msg *, struct netlink_skb_parms *));

2024-01-15 09:28:36

by Keqi Wang

Subject: Re:Re: [PATCH] connector: Change the judgment conditions for clearing proc_event_num_listeners

From: wangkeqi <[email protected]>

It is inaccurate to judge whether proc_event_num_listeners is
cleared by cn_netlink_send_mult returning -ESRCH.
In the case of stress-ng netlink-proc, -ESRCH will always be returned,
because netlink_broadcast_filtered will return -ESRCH,
which may cause stress-ng netlink-proc performance degradation.
Therefore, the judgment condition is modified to whether
there is a listener.

Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-lkp/[email protected]
Signed-off-by: wangkeqi <[email protected]>
Cc: [email protected]
---
drivers/connector/cn_proc.c | 6 ++++--
drivers/connector/connector.c | 6 ++++++
include/linux/connector.h | 1 +
3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index 3d5e6d705..b09f74ed3 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -108,8 +108,10 @@ static inline void send_msg(struct cn_msg *msg)
filter_data[1] = 0;
}

- if (cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
- cn_filter, (void *)filter_data) == -ESRCH)
+ if (netlink_has_listeners(get_cdev_nls(), CN_IDX_PROC))
+ cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
+ cn_filter, (void *)filter_data);
+ else
atomic_set(&proc_event_num_listeners, 0);

local_unlock(&local_event.lock);
diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index 7f7b94f61..1b2cd410e 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -129,6 +129,12 @@ int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 __group,
}
EXPORT_SYMBOL_GPL(cn_netlink_send);

+struct sock *get_cdev_nls(void)
+{
+ return cdev.nls;
+}
+EXPORT_SYMBOL_GPL(get_cdev_nls);
+
/*
* Callback helper - queues work and setup destructor for given data.
*/
diff --git a/include/linux/connector.h b/include/linux/connector.h
index cec2d99ae..255466aea 100644
--- a/include/linux/connector.h
+++ b/include/linux/connector.h
@@ -127,6 +127,7 @@ int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid,
*/
int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_mask);

+struct sock *get_cdev_nls(void);
int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
const struct cb_id *id,
void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
--

2.27.0


The last email is not plain text, I will send it again.











At 2024-01-15 15:57:23, "Yin, Fengwei" <[email protected]> wrote:
>
>
>On 1/15/2024 3:51 PM, wangkeqi wrote:
>> From: wangkeqi <[email protected]>
>>
>> It is inaccurate to judge whether proc_event_num_listeners is
>> cleared by cn_netlink_send_mult returning -ESRCH.
>> In the case of stress-ng netlink-proc, -ESRCH will always be returned,
>> because netlink_broadcast_filtered will return -ESRCH,
>> which may cause stress-ng netlink-proc performance degradation.
>> Therefore, the judgment condition is modified to whether
>> there is a listener.
>>
>> Signed-off-by: wangkeqi <[email protected]>
>
>Regarding the original report:
>
>If you fix the issue in a separate patch/commit (i.e. not just a new
>version of
>the same patch/commit), kindly add following tags
>| Reported-by: kernel test robot <[email protected]>
>| Closes:
>https://lore.kernel.org/oe-lkp/[email protected]
>
>
>Could you please add the tag? Thanks.
>
>> ---
>> drivers/connector/cn_proc.c | 6 ++++--
>> drivers/connector/connector.c | 6 ++++++
>> include/linux/connector.h | 1 +
>> 3 files changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
>> index 3d5e6d705..b09f74ed3 100644
>> --- a/drivers/connector/cn_proc.c
>> +++ b/drivers/connector/cn_proc.c
>> @@ -108,8 +108,10 @@ static inline void send_msg(struct cn_msg *msg)
>> filter_data[1] = 0;
>> }
>>
>> - if (cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
>> - cn_filter, (void *)filter_data) == -ESRCH)
>> + if (netlink_has_listeners(get_cdev_nls(), CN_IDX_PROC))
>> + cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
>> + cn_filter, (void *)filter_data);
>> + else
>> atomic_set(&proc_event_num_listeners, 0);
>>
>> local_unlock(&local_event.lock);
>> diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
>> index 7f7b94f61..1b2cd410e 100644
>> --- a/drivers/connector/connector.c
>> +++ b/drivers/connector/connector.c
>> @@ -129,6 +129,12 @@ int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 __group,
>> }
>> EXPORT_SYMBOL_GPL(cn_netlink_send);
>>
>> +struct sock *get_cdev_nls(void)
>> +{
>> + return cdev.nls;
>> +}
>> +EXPORT_SYMBOL_GPL(get_cdev_nls);
>> +
>> /*
>> * Callback helper - queues work and setup destructor for given data.
>> */
>> diff --git a/include/linux/connector.h b/include/linux/connector.h
>> index cec2d99ae..255466aea 100644
>> --- a/include/linux/connector.h
>> +++ b/include/linux/connector.h
>> @@ -127,6 +127,7 @@ int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid,
>> */
>> int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_mask);
>>
>> +struct sock *get_cdev_nls(void);
>> int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
>> const struct cb_id *id,
>> void (*callback)(struct cn_msg *, struct netlink_skb_parms *));

2024-01-15 23:59:56

by Jakub Kicinski

Subject: Re: [PATCH] connector: Change the judgment conditions for clearing proc_event_num_listeners

On Mon, 15 Jan 2024 17:26:39 +0800 (CST) wangkeqi wrote:
> From: wangkeqi <[email protected]>
>
> It is inaccurate to judge whether proc_event_num_listeners is
> cleared by cn_netlink_send_mult returning -ESRCH.
> In the case of stress-ng netlink-proc, -ESRCH will always be returned,
> because netlink_broadcast_filtered will return -ESRCH,
> which may cause stress-ng netlink-proc performance degradation.
> Therefore, the judgment condition is modified to whether
> there is a listener.
>
> Reported-by: kernel test robot <[email protected]>
> Closes: https://lore.kernel.org/oe-lkp/[email protected]
> Signed-off-by: wangkeqi <[email protected]>
> Cc: [email protected]

Please stop posting the patches as a reply to the previous submission
with a quote at the end.. Post the new version generated by git with
--subject-prefix="PATCH net v2" and send it with git send-email as
a new thread.

Please add an appropriate Fixes tag.
--
pw-bot: cr