The 3 functions that want access to the taprio_list:
taprio_dev_notifier(), taprio_destroy() and taprio_init() are all called
with the rtnl_mutex held, therefore implicitly serialized with respect
to each other. A spin lock serves no purpose.
Signed-off-by: Vladimir Oltean <[email protected]>
---
net/sched/sch_taprio.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 1ab92968c1e3..163255e0cd77 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -27,7 +27,6 @@
#include <net/tcp.h>
static LIST_HEAD(taprio_list);
-static DEFINE_SPINLOCK(taprio_list_lock);
#define TAPRIO_ALL_GATES_OPEN -1
@@ -1082,7 +1081,6 @@ static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event,
if (event != NETDEV_UP && event != NETDEV_CHANGE)
return NOTIFY_DONE;
- spin_lock(&taprio_list_lock);
list_for_each_entry(q, &taprio_list, taprio_list) {
qdev = qdisc_dev(q->root);
if (qdev == dev) {
@@ -1090,7 +1088,6 @@ static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event,
break;
}
}
- spin_unlock(&taprio_list_lock);
if (found)
taprio_set_picos_per_byte(dev, q);
@@ -1602,9 +1599,7 @@ static void taprio_destroy(struct Qdisc *sch)
struct sched_gate_list *oper, *admin;
unsigned int i;
- spin_lock(&taprio_list_lock);
list_del(&q->taprio_list);
- spin_unlock(&taprio_list_lock);
/* Note that taprio_reset() might not be called if an error
* happens in qdisc_create(), after taprio_init() has been called.
@@ -1653,9 +1648,7 @@ static int taprio_init(struct Qdisc *sch, struct nlattr *opt,
q->clockid = -1;
q->flags = TAPRIO_FLAGS_INVALID;
- spin_lock(&taprio_list_lock);
list_add(&q->taprio_list, &taprio_list);
- spin_unlock(&taprio_list_lock);
if (sch->parent != TC_H_ROOT) {
NL_SET_ERR_MSG_MOD(extack, "Can only be attached as root qdisc");
--
2.34.1
Vladimir Oltean <[email protected]> writes:
> The 3 functions that want access to the taprio_list:
> taprio_dev_notifier(), taprio_destroy() and taprio_init() are all called
> with the rtnl_mutex held, therefore implicitly serialized with respect
> to each other. A spin lock serves no purpose.
>
> Signed-off-by: Vladimir Oltean <[email protected]>
> ---
> net/sched/sch_taprio.c | 7 -------
> 1 file changed, 7 deletions(-)
>
> diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
> index 1ab92968c1e3..163255e0cd77 100644
> --- a/net/sched/sch_taprio.c
> +++ b/net/sched/sch_taprio.c
> @@ -27,7 +27,6 @@
> #include <net/tcp.h>
>
> static LIST_HEAD(taprio_list);
> -static DEFINE_SPINLOCK(taprio_list_lock);
>
> #define TAPRIO_ALL_GATES_OPEN -1
>
> @@ -1082,7 +1081,6 @@ static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event,
> if (event != NETDEV_UP && event != NETDEV_CHANGE)
> return NOTIFY_DONE;
>
> - spin_lock(&taprio_list_lock);
> list_for_each_entry(q, &taprio_list, taprio_list) {
> qdev = qdisc_dev(q->root);
> if (qdev == dev) {
Optional simplification: do you mind removing 'found' and moving the
call to taprio_set_picos_per_byte() here?
Anyway,
Acked-by: Vinicius Costa Gomes <[email protected]>
> @@ -1090,7 +1088,6 @@ static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event,
> break;
> }
> }
> - spin_unlock(&taprio_list_lock);
>
> if (found)
> taprio_set_picos_per_byte(dev, q);
> @@ -1602,9 +1599,7 @@ static void taprio_destroy(struct Qdisc *sch)
> struct sched_gate_list *oper, *admin;
> unsigned int i;
>
> - spin_lock(&taprio_list_lock);
> list_del(&q->taprio_list);
> - spin_unlock(&taprio_list_lock);
>
> /* Note that taprio_reset() might not be called if an error
> * happens in qdisc_create(), after taprio_init() has been called.
> @@ -1653,9 +1648,7 @@ static int taprio_init(struct Qdisc *sch, struct nlattr *opt,
> q->clockid = -1;
> q->flags = TAPRIO_FLAGS_INVALID;
>
> - spin_lock(&taprio_list_lock);
> list_add(&q->taprio_list, &taprio_list);
> - spin_unlock(&taprio_list_lock);
>
> if (sch->parent != TC_H_ROOT) {
> NL_SET_ERR_MSG_MOD(extack, "Can only be attached as root qdisc");
> --
> 2.34.1
>
Cheers,
--
Vinicius
On Wed, Sep 21, 2022 at 04:09:55PM -0700, Vinicius Costa Gomes wrote:
> Optional simplification: do you mind removing 'found' and moving the
> call to taprio_set_picos_per_byte() here?
Yes, I can do that (in a follow-up patch).
> Anyway,
>
> Acked-by: Vinicius Costa Gomes <[email protected]>
Thanks.
Hello:
This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <[email protected]>:
On Wed, 21 Sep 2022 12:56:31 +0300 you wrote:
> The 3 functions that want access to the taprio_list:
> taprio_dev_notifier(), taprio_destroy() and taprio_init() are all called
> with the rtnl_mutex held, therefore implicitly serialized with respect
> to each other. A spin lock serves no purpose.
>
> Signed-off-by: Vladimir Oltean <[email protected]>
>
> [...]
Here is the summary with links:
- [net-next] net/sched: taprio: remove unnecessary taprio_list_lock
https://git.kernel.org/netdev/net-next/c/a2c2a4ddc27d
You are awesome, thank you!
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