| Message ID | 20220915105046.2404072-2-vladimir.oltean@nxp.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | c8cbe123be6de9deff5e5312af8848362a919f97 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Small tc-taprio improvements | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/fixes_present | success | Fixes tag not required for -next series |
| netdev/subject_prefix | success | Link |
| netdev/cover_letter | success | Series has a cover letter |
| netdev/patch_count | success | Link |
| netdev/header_inline | success | No static functions without inline keyword in header files |
| netdev/build_32bit | success | Errors and warnings before: 2 this patch: 2 |
| netdev/cc_maintainers | success | CCed 9 of 9 maintainers |
| netdev/build_clang | success | Errors and warnings before: 0 this patch: 0 |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/check_selftest | success | No net selftest shell script |
| netdev/verify_fixes | success | No Fixes tag |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 2 this patch: 2 |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 18 lines checked |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 5bffc37022e0..550afbbae8bc 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1194,16 +1194,10 @@ static void taprio_offload_config_changed(struct taprio_sched *q) { struct sched_gate_list *oper, *admin; - spin_lock(&q->current_entry_lock); - - oper = rcu_dereference_protected(q->oper_sched, - lockdep_is_held(&q->current_entry_lock)); - admin = rcu_dereference_protected(q->admin_sched, - lockdep_is_held(&q->current_entry_lock)); + oper = rtnl_dereference(q->oper_sched); + admin = rtnl_dereference(q->admin_sched); switch_schedules(q, &admin, &oper); - - spin_unlock(&q->current_entry_lock); } static u32 tc_map_to_queue_mask(struct net_device *dev, u32 tc_mask)
The locking in taprio_offload_config_changed() is wrong (but also inconsequentially so). The current_entry_lock does not serialize changes to the admin and oper schedules, only to the current entry. In fact, the rtnl_mutex does that, and that is taken at the time when taprio_change() is called. Replace the rcu_dereference_protected() method with the proper RCU annotation, and drop the unnecessary spin lock. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> --- v1->v2: patch is new net/sched/sch_taprio.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-)