diff options
| -rw-r--r-- | drivers/android/binder_alloc.c | 43 |
1 files changed, 35 insertions, 8 deletions
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index 3f3b7b253445..64fd96eada31 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -332,6 +332,35 @@ err_no_vma: return vma ? -ENOMEM : -ESRCH; } + +static inline void binder_alloc_set_vma(struct binder_alloc *alloc, + struct vm_area_struct *vma) +{ + if (vma) + alloc->vma_vm_mm = vma->vm_mm; + /* + * If we see alloc->vma is not NULL, buffer data structures set up + * completely. Look at smp_rmb side binder_alloc_get_vma. + * We also want to guarantee new alloc->vma_vm_mm is always visible + * if alloc->vma is set. + */ + smp_wmb(); + alloc->vma = vma; +} + +static inline struct vm_area_struct *binder_alloc_get_vma( + struct binder_alloc *alloc) +{ + struct vm_area_struct *vma = NULL; + + if (alloc->vma) { + /* Look at description in binder_alloc_set_vma */ + smp_rmb(); + vma = alloc->vma; + } + return vma; +} + static struct binder_buffer *binder_alloc_new_buf_locked( struct binder_alloc *alloc, size_t data_size, @@ -348,7 +377,7 @@ static struct binder_buffer *binder_alloc_new_buf_locked( size_t size, data_offsets_size; int ret; - if (alloc->vma == NULL) { + if (!binder_alloc_get_vma(alloc)) { binder_alloc_debug(BINDER_DEBUG_USER_ERROR, "%d: binder_alloc_buf, no vma\n", alloc->pid); @@ -723,9 +752,7 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc, buffer->free = 1; binder_insert_free_buffer(alloc, buffer); alloc->free_async_space = alloc->buffer_size / 2; - barrier(); - alloc->vma = vma; - alloc->vma_vm_mm = vma->vm_mm; + binder_alloc_set_vma(alloc, vma); mmgrab(alloc->vma_vm_mm); return 0; @@ -754,10 +781,10 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc) int buffers, page_count; struct binder_buffer *buffer; - BUG_ON(alloc->vma); - buffers = 0; mutex_lock(&alloc->mutex); + BUG_ON(alloc->vma); + while ((n = rb_first(&alloc->allocated_buffers))) { buffer = rb_entry(n, struct binder_buffer, rb_node); @@ -900,7 +927,7 @@ int binder_alloc_get_allocated_count(struct binder_alloc *alloc) */ void binder_alloc_vma_close(struct binder_alloc *alloc) { - WRITE_ONCE(alloc->vma, NULL); + binder_alloc_set_vma(alloc, NULL); } /** @@ -935,7 +962,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item, index = page - alloc->pages; page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE; - vma = alloc->vma; + vma = binder_alloc_get_vma(alloc); if (vma) { if (!mmget_not_zero(alloc->vma_vm_mm)) goto err_mmget; |