diff options
Diffstat (limited to 'kernel/bpf/stackmap.c')
| -rw-r--r-- | kernel/bpf/stackmap.c | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index d09d4c3fe547..f7e8d766d128 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -272,13 +272,10 @@ struct stack_map_vma_lock { /* * Acquire a stable read-side reference on the VMA covering @ip. * - * With CONFIG_PER_VMA_LOCK=y this returns a VMA with its per-VMA read - * lock held and mmap_lock dropped, so the caller may sleep. - * - * With CONFIG_PER_VMA_LOCK=n it returns a VMA with mmap_lock still - * held; the caller must snapshot any fields it needs and pin vm_file - * with get_file() before stack_map_unlock_vma() drops mmap_lock, as - * the VMA may be split, merged, or freed after that. + * On NOMMU configurations, returns with the mmap_lock held. If the MMU + * is enabled, the per-VMA lock will be held instead. The lock + * should be released with stack_map_unlock_vma() which will release the + * appropriate lock. Once the lock is released, the VMA may be freed. * * Returns NULL on failure, in which case no lock is held. */ @@ -288,7 +285,6 @@ stack_map_lock_vma(struct stack_map_vma_lock *lock, unsigned long ip) struct mm_struct *mm = lock->mm; struct vm_area_struct *vma; - /* noop under !CONFIG_PER_VMA_LOCK */ vma = lock_vma_under_rcu(mm, ip); if (vma) { lock->vma = vma; @@ -308,21 +304,20 @@ stack_map_lock_vma(struct stack_map_vma_lock *lock, unsigned long ip) return NULL; } -#ifdef CONFIG_PER_VMA_LOCK +#ifdef CONFIG_MMU if (!vma_start_read_locked(vma)) { mmap_read_unlock(mm); return NULL; } mmap_read_unlock(mm); #endif - lock->vma = vma; return vma; } static void stack_map_unlock_vma(struct stack_map_vma_lock *lock) { -#ifdef CONFIG_PER_VMA_LOCK +#ifdef CONFIG_MMU vma_end_read(lock->vma); #else mmap_read_unlock(lock->mm); |