diff options
Diffstat (limited to 'drivers/android/binder_alloc.c')
| -rw-r--r-- | drivers/android/binder_alloc.c | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index b2b97ff19ba2..fcfaf1b899c8 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -1143,19 +1143,28 @@ enum lru_status binder_alloc_free_page(struct list_head *item, struct vm_area_struct *vma; struct page *page_to_free; unsigned long page_addr; + int mm_locked = 0; size_t index; if (!mmget_not_zero(mm)) goto err_mmget; - if (!mmap_read_trylock(mm)) - goto err_mmap_read_lock_failed; - if (!mutex_trylock(&alloc->mutex)) - goto err_get_alloc_mutex_failed; index = mdata->page_index; page_addr = alloc->vm_start + index * PAGE_SIZE; - vma = vma_lookup(mm, page_addr); + /* attempt per-vma lock first */ + vma = lock_vma_under_rcu(mm, page_addr); + if (!vma) { + /* fall back to mmap_lock */ + if (!mmap_read_trylock(mm)) + goto err_mmap_read_lock_failed; + mm_locked = 1; + vma = vma_lookup(mm, page_addr); + } + + if (!mutex_trylock(&alloc->mutex)) + goto err_get_alloc_mutex_failed; + /* * Since a binder_alloc can only be mapped once, we ensure * the vma corresponds to this mapping by checking whether @@ -1183,7 +1192,10 @@ enum lru_status binder_alloc_free_page(struct list_head *item, } mutex_unlock(&alloc->mutex); - mmap_read_unlock(mm); + if (mm_locked) + mmap_read_unlock(mm); + else + vma_end_read(vma); mmput_async(mm); binder_free_page(page_to_free); @@ -1192,7 +1204,10 @@ enum lru_status binder_alloc_free_page(struct list_head *item, err_invalid_vma: mutex_unlock(&alloc->mutex); err_get_alloc_mutex_failed: - mmap_read_unlock(mm); + if (mm_locked) + mmap_read_unlock(mm); + else + vma_end_read(vma); err_mmap_read_lock_failed: mmput_async(mm); err_mmget: |