diff options
| -rw-r--r-- | include/linux/perf_event.h | 3 | ||||
| -rw-r--r-- | kernel/events/core.c | 37 | ||||
| -rw-r--r-- | kernel/events/internal.h | 3 |
3 files changed, 24 insertions, 19 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index f463a46424e..c5b6dbf9c2f 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -389,8 +389,7 @@ struct perf_event { /* mmap bits */ struct mutex mmap_mutex; atomic_t mmap_count; - int mmap_locked; - struct user_struct *mmap_user; + struct ring_buffer *rb; struct list_head rb_entry; diff --git a/kernel/events/core.c b/kernel/events/core.c index 9dc297faf7c..ae752cd4a08 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2917,7 +2917,7 @@ static void free_event_rcu(struct rcu_head *head) kfree(event); } -static void ring_buffer_put(struct ring_buffer *rb); +static bool ring_buffer_put(struct ring_buffer *rb); static void free_event(struct perf_event *event) { @@ -3582,13 +3582,13 @@ static struct ring_buffer *ring_buffer_get(struct perf_event *event) return rb; } -static void ring_buffer_put(struct ring_buffer *rb) +static bool ring_buffer_put(struct ring_buffer *rb) { struct perf_event *event, *n; unsigned long flags; if (!atomic_dec_and_test(&rb->refcount)) - return; + return false; spin_lock_irqsave(&rb->event_lock, flags); list_for_each_entry_safe(event, n, &rb->event_list, rb_entry) { @@ -3598,6 +3598,7 @@ static void ring_buffer_put(struct ring_buffer *rb) spin_unlock_irqrestore(&rb->event_lock, flags); call_rcu(&rb->rcu_head, rb_free_rcu); + return true; } static void perf_mmap_open(struct vm_area_struct *vma) @@ -3612,18 +3613,20 @@ static void perf_mmap_close(struct vm_area_struct *vma) struct perf_event *event = vma->vm_file->private_data; if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) { - unsigned long size = perf_data_size(event->rb); - struct user_struct *user = event->mmap_user; struct ring_buffer *rb = event->rb; + struct user_struct *mmap_user = rb->mmap_user; + int mmap_locked = rb->mmap_locked; + unsigned long size = perf_data_size(rb); - atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm); - vma->vm_mm->pinned_vm -= event->mmap_locked; rcu_assign_pointer(event->rb, NULL); ring_buffer_detach(event, rb); mutex_unlock(&event->mmap_mutex); - ring_buffer_put(rb); - free_uid(user); + if (ring_buffer_put(rb)) { + atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); + vma->vm_mm->pinned_vm -= mmap_locked; + free_uid(mmap_user); + } } } @@ -3676,9 +3679,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) WARN_ON_ONCE(event->ctx->parent_ctx); mutex_lock(&event->mmap_mutex); if (event->rb) { - if (event->rb->nr_pages == nr_pages) - atomic_inc(&event->rb->refcount); - else + if (event->rb->nr_pages != nr_pages) ret = -EINVAL; goto unlock; } @@ -3720,12 +3721,14 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) ret = -ENOMEM; goto unlock; } - rcu_assign_pointer(event->rb, rb); + + rb->mmap_locked = extra; + rb->mmap_user = get_current_user(); atomic_long_add(user_extra, &user->locked_vm); - event->mmap_locked = extra; - event->mmap_user = get_current_user(); - vma->vm_mm->pinned_vm += event->mmap_locked; + vma->vm_mm->pinned_vm += extra; + + rcu_assign_pointer(event->rb, rb); perf_event_update_userpage(event); @@ -3734,7 +3737,7 @@ unlock: atomic_inc(&event->mmap_count); mutex_unlock(&event->mmap_mutex); - vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; + vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; vma->vm_ops = &perf_mmap_vmops; return ret; diff --git a/kernel/events/internal.h b/kernel/events/internal.h index eb675c4d59d..5bc6c8e9b85 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -31,6 +31,9 @@ struct ring_buffer { spinlock_t event_lock; struct list_head event_list; + int mmap_locked; + struct user_struct *mmap_user; + struct perf_event_mmap_page *user_page; void *data_pages[0]; }; |