sched/core: Convert get_task_struct() to return the task

Returning the pointer that was passed in allows us to write
slightly more idiomatic code.  Convert a few users.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190704221323.24290-1-willy@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 0497091..3d90ed8 100644 (file)
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -105,7 +105,11 @@ extern void sched_exec(void);
 #define sched_exec()   {}
 #endif
 
-#define get_task_struct(tsk) do { refcount_inc(&(tsk)->usage); } while(0)
+static inline struct task_struct *get_task_struct(struct task_struct *t)
+{
+       refcount_inc(&t->usage);
+       return t;
+}
 
 extern void __put_task_struct(struct task_struct *t);
 

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 026a145..ea5e813 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4089,10 +4089,8 @@ alloc_perf_context(struct pmu *pmu, struct task_struct *task)
                return NULL;
 
        __perf_event_init_context(ctx);
-       if (task) {
-               ctx->task = task;
-               get_task_struct(task);
-       }
+       if (task)
+               ctx->task = get_task_struct(task);
        ctx->pmu = pmu;
 
        return ctx;
@@ -10355,8 +10353,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
                 * and we cannot use the ctx information because we need the
                 * pmu before we get a ctx.
                 */
-               get_task_struct(task);
-               event->hw.target = task;
+               event->hw.target = get_task_struct(task);
        }
 
        event->clock = &local_clock;

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index e8f7f17..9d50fbe 100644 (file)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1255,8 +1255,7 @@ setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
         * the thread dies to avoid that the interrupt code
         * references an already freed task_struct.
         */
-       get_task_struct(t);
-       new->thread = t;
+       new->thread = get_task_struct(t);
        /*
         * Tell the thread to set its affinity. This is
         * important for shared interrupt handlers as we do

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index fa83d36..2874bf5 100644 (file)
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -628,8 +628,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
                }
 
                /* [10] Grab the next task, i.e. owner of @lock */
-               task = rt_mutex_owner(lock);
-               get_task_struct(task);
+               task = get_task_struct(rt_mutex_owner(lock));
                raw_spin_lock(&task->pi_lock);
 
                /*
@@ -709,8 +708,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
        }
 
        /* [10] Grab the next task, i.e. the owner of @lock */
-       task = rt_mutex_owner(lock);
-       get_task_struct(task);
+       task = get_task_struct(rt_mutex_owner(lock));
        raw_spin_lock(&task->pi_lock);
 
        /* [11] requeue the pi waiters if necessary */

diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 743b2b5..5e43b96 100644 (file)
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -579,8 +579,7 @@ probe_wakeup(void *ignore, struct task_struct *p)
        else
                tracing_dl = 0;
 
-       wakeup_task = p;
-       get_task_struct(wakeup_task);
+       wakeup_task = get_task_struct(p);
 
        local_save_flags(flags);