[PATCH] MIPS: Use rcu to lookup a task in mipsmt_sys_sched_setaffinity()

From: Davidlohr Bueso
Date: Mon Aug 31 2020 - 16:29:37 EST


The call simply looks up the corresponding task (without iterating
the tasklist), which is safe under rcu instead of the tasklist_lock.
In addition, the setaffinity counter part already does this.

Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
---
arch/mips/kernel/mips-mt-fpaff.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/kernel/mips-mt-fpaff.c b/arch/mips/kernel/mips-mt-fpaff.c
index 1a08428eedcf..6c590ef27648 100644
--- a/arch/mips/kernel/mips-mt-fpaff.c
+++ b/arch/mips/kernel/mips-mt-fpaff.c
@@ -167,7 +167,7 @@ asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len,
return -EINVAL;

get_online_cpus();
- read_lock(&tasklist_lock);
+ rcu_read_lock();

retval = -ESRCH;
p = find_process_by_pid(pid);
@@ -181,7 +181,7 @@ asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len,
cpumask_and(&mask, &allowed, cpu_active_mask);

out_unlock:
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
put_online_cpus();
if (retval)
return retval;
--
2.26.2