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Subject[PATCH 05/10] perf_event: __rcu annotations
Date
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
include/linux/perf_event.h | 10 ++++----
include/linux/sched.h | 2 +-
kernel/perf_event.c | 52 ++++++++++++++++++++++----------------------
3 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index a177698..c0d85e3 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -569,11 +569,11 @@ typedef void (*perf_overflow_handler_t)(struct perf_event *, int,
struct perf_event {
#ifdef CONFIG_PERF_EVENTS
struct list_head group_entry;
- struct list_head event_entry;
+ struct rcu_list_head event_entry;
struct list_head sibling_list;
int nr_siblings;
struct perf_event *group_leader;
- struct perf_event *output;
+ struct perf_event __rcu *output;
const struct pmu *pmu;

enum perf_event_active_state state;
@@ -634,7 +634,7 @@ struct perf_event {
/* mmap bits */
struct mutex mmap_mutex;
atomic_t mmap_count;
- struct perf_mmap_data *data;
+ struct perf_mmap_data __rcu *data;

/* poll related */
wait_queue_head_t waitq;
@@ -682,7 +682,7 @@ struct perf_event_context {
struct mutex mutex;

struct list_head group_list;
- struct list_head event_list;
+ struct rcu_list_head event_list;
int nr_events;
int nr_active;
int is_active;
@@ -700,7 +700,7 @@ struct perf_event_context {
* These fields let us detect when two contexts have both
* been cloned (inherited) from a common ancestor.
*/
- struct perf_event_context *parent_ctx;
+ struct perf_event_context __rcu *parent_ctx;
u64 parent_gen;
u64 generation;
int pin_count;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 52a33eb..f14d925 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1502,7 +1502,7 @@ struct task_struct {
struct futex_pi_state *pi_state_cache;
#endif
#ifdef CONFIG_PERF_EVENTS
- struct perf_event_context *perf_event_ctxp;
+ struct perf_event_context __rcu *perf_event_ctxp;
struct mutex perf_event_mutex;
struct list_head perf_event_list;
#endif
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 2ae7409..18701de 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -150,7 +150,7 @@ static void put_ctx(struct perf_event_context *ctx)
{
if (atomic_dec_and_test(&ctx->refcount)) {
if (ctx->parent_ctx)
- put_ctx(ctx->parent_ctx);
+ put_ctx(__rcu_dereference(ctx->parent_ctx));
if (ctx->task)
put_task_struct(ctx->task);
call_rcu(&ctx->rcu_head, free_ctx);
@@ -160,7 +160,7 @@ static void put_ctx(struct perf_event_context *ctx)
static void unclone_ctx(struct perf_event_context *ctx)
{
if (ctx->parent_ctx) {
- put_ctx(ctx->parent_ctx);
+ put_ctx(__rcu_dereference(ctx->parent_ctx));
ctx->parent_ctx = NULL;
}
}
@@ -1129,8 +1129,8 @@ static void __perf_event_sync_stat(struct perf_event *event,
perf_event_update_userpage(next_event);
}

-#define list_next_entry(pos, member) \
- list_entry(pos->member.next, typeof(*pos), member)
+#define list_next_entry_rcu(pos, member) \
+ list_entry_rcu(pos->member.next, typeof(*pos), member)

static void perf_event_sync_stat(struct perf_event_context *ctx,
struct perf_event_context *next_ctx)
@@ -1142,10 +1142,10 @@ static void perf_event_sync_stat(struct perf_event_context *ctx,

update_context_time(ctx);

- event = list_first_entry(&ctx->event_list,
+ event = list_first_entry_rcu(&ctx->event_list,
struct perf_event, event_entry);

- next_event = list_first_entry(&next_ctx->event_list,
+ next_event = list_first_entry_rcu(&next_ctx->event_list,
struct perf_event, event_entry);

while (&event->event_entry != &ctx->event_list &&
@@ -1153,8 +1153,8 @@ static void perf_event_sync_stat(struct perf_event_context *ctx,

__perf_event_sync_stat(event, next_event);

- event = list_next_entry(event, event_entry);
- next_event = list_next_entry(next_event, event_entry);
+ event = list_next_entry_rcu(event, event_entry);
+ next_event = list_next_entry_rcu(next_event, event_entry);
}
}

@@ -1173,7 +1173,7 @@ void perf_event_task_sched_out(struct task_struct *task,
struct task_struct *next, int cpu)
{
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
- struct perf_event_context *ctx = task->perf_event_ctxp;
+ struct perf_event_context *ctx = rcu_dereference(task->perf_event_ctxp);
struct perf_event_context *next_ctx;
struct perf_event_context *parent;
struct pt_regs *regs;
@@ -1187,7 +1187,7 @@ void perf_event_task_sched_out(struct task_struct *task,

rcu_read_lock();
parent = rcu_dereference(ctx->parent_ctx);
- next_ctx = next->perf_event_ctxp;
+ next_ctx = rcu_dereference(next->perf_event_ctxp);
if (parent && next_ctx &&
rcu_dereference(next_ctx->parent_ctx) == parent) {
/*
@@ -1206,8 +1206,8 @@ void perf_event_task_sched_out(struct task_struct *task,
* XXX do we need a memory barrier of sorts
* wrt to rcu_dereference() of perf_event_ctxp
*/
- task->perf_event_ctxp = next_ctx;
- next->perf_event_ctxp = ctx;
+ __rcu_assign_pointer(task->perf_event_ctxp, next_ctx);
+ __rcu_assign_pointer(next->perf_event_ctxp, ctx);
ctx->task = next;
next_ctx->task = task;
do_switch = 0;
@@ -1329,7 +1329,7 @@ __perf_event_sched_in(struct perf_event_context *ctx,
void perf_event_task_sched_in(struct task_struct *task, int cpu)
{
struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
- struct perf_event_context *ctx = task->perf_event_ctxp;
+ struct perf_event_context *ctx = __rcu_dereference(task->perf_event_ctxp);

if (likely(!ctx))
return;
@@ -1470,7 +1470,7 @@ void perf_event_task_tick(struct task_struct *curr, int cpu)
return;

cpuctx = &per_cpu(perf_cpu_context, cpu);
- ctx = curr->perf_event_ctxp;
+ ctx = rcu_dereference(curr->perf_event_ctxp);

perf_ctx_adjust_freq(&cpuctx->ctx);
if (ctx)
@@ -1501,7 +1501,7 @@ static void perf_event_enable_on_exec(struct task_struct *task)
int enabled = 0;

local_irq_save(flags);
- ctx = task->perf_event_ctxp;
+ ctx = __rcu_dereference(task->perf_event_ctxp);
if (!ctx || !ctx->nr_events)
goto out;

@@ -1591,7 +1591,7 @@ __perf_event_init_context(struct perf_event_context *ctx,
raw_spin_lock_init(&ctx->lock);
mutex_init(&ctx->mutex);
INIT_LIST_HEAD(&ctx->group_list);
- INIT_LIST_HEAD(&ctx->event_list);
+ INIT_LIST_HEAD_RCU(&ctx->event_list);
atomic_set(&ctx->refcount, 1);
ctx->task = task;
}
@@ -2366,7 +2366,7 @@ static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)

static void perf_mmap_data_release(struct perf_event *event)
{
- struct perf_mmap_data *data = event->data;
+ struct perf_mmap_data *data = __rcu_dereference(event->data);

WARN_ON(atomic_read(&event->mmap_count));

@@ -2387,7 +2387,7 @@ static void perf_mmap_close(struct vm_area_struct *vma)

WARN_ON_ONCE(event->ctx->parent_ctx);
if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
- unsigned long size = perf_data_size(event->data);
+ unsigned long size = perf_data_size(__rcu_dereference(event->data));
struct user_struct *user = current_user();

atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
@@ -4421,7 +4421,7 @@ perf_event_alloc(struct perf_event_attr *attr,
INIT_LIST_HEAD(&event->child_list);

INIT_LIST_HEAD(&event->group_entry);
- INIT_LIST_HEAD(&event->event_entry);
+ INIT_LIST_HEAD_RCU(&event->event_entry);
INIT_LIST_HEAD(&event->sibling_list);
init_waitqueue_head(&event->waitq);

@@ -4629,7 +4629,7 @@ static int perf_event_set_output(struct perf_event *event, int output_fd)

set:
mutex_lock(&event->mmap_mutex);
- old_output = event->output;
+ old_output = __rcu_dereference(event->output);
rcu_assign_pointer(event->output, output_event);
mutex_unlock(&event->mmap_mutex);

@@ -4999,7 +4999,7 @@ void perf_event_exit_task(struct task_struct *child)
* scheduled, so we are now safe from rescheduling changing
* our context.
*/
- child_ctx = child->perf_event_ctxp;
+ child_ctx = __rcu_dereference(child->perf_event_ctxp);
__perf_event_task_sched_out(child_ctx);

/*
@@ -5062,7 +5062,7 @@ again:
*/
void perf_event_free_task(struct task_struct *task)
{
- struct perf_event_context *ctx = task->perf_event_ctxp;
+ struct perf_event_context *ctx = __rcu_dereference(task->perf_event_ctxp);
struct perf_event *event, *tmp;

if (!ctx)
@@ -5160,7 +5160,7 @@ int perf_event_init_task(struct task_struct *child)
}

__perf_event_init_context(child_ctx, child);
- child->perf_event_ctxp = child_ctx;
+ __rcu_assign_pointer(child->perf_event_ctxp, child_ctx);
get_task_struct(child);
}

@@ -5183,13 +5183,13 @@ int perf_event_init_task(struct task_struct *child)
*/
cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
if (cloned_ctx) {
- child_ctx->parent_ctx = cloned_ctx;
+ __rcu_assign_pointer(child_ctx->parent_ctx, cloned_ctx);
child_ctx->parent_gen = parent_ctx->parent_gen;
} else {
- child_ctx->parent_ctx = parent_ctx;
+ __rcu_assign_pointer(child_ctx->parent_ctx, parent_ctx);
child_ctx->parent_gen = parent_ctx->generation;
}
- get_ctx(child_ctx->parent_ctx);
+ get_ctx(__rcu_dereference(child_ctx->parent_ctx));
}

mutex_unlock(&parent_ctx->mutex);
--
1.6.3.3


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