diff options
Diffstat (limited to 'drivers/staging/comedi/comedi_buf.c')
| -rw-r--r-- | drivers/staging/comedi/comedi_buf.c | 37 |
1 files changed, 35 insertions, 2 deletions
diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c index 924fce977985..257595016161 100644 --- a/drivers/staging/comedi/comedi_buf.c +++ b/drivers/staging/comedi/comedi_buf.c @@ -61,6 +61,8 @@ static void __comedi_buf_free(struct comedi_device *dev, struct comedi_subdevice *s) { struct comedi_async *async = s->async; + struct comedi_buf_map *bm; + unsigned long flags; if (async->prealloc_buf) { vunmap(async->prealloc_buf); @@ -68,8 +70,11 @@ static void __comedi_buf_free(struct comedi_device *dev, async->prealloc_bufsz = 0; } - comedi_buf_map_put(async->buf_map); + spin_lock_irqsave(&s->spin_lock, flags); + bm = async->buf_map; async->buf_map = NULL; + spin_unlock_irqrestore(&s->spin_lock, flags); + comedi_buf_map_put(bm); } static void __comedi_buf_alloc(struct comedi_device *dev, @@ -80,6 +85,7 @@ static void __comedi_buf_alloc(struct comedi_device *dev, struct page **pages = NULL; struct comedi_buf_map *bm; struct comedi_buf_page *buf; + unsigned long flags; unsigned i; if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) { @@ -92,8 +98,10 @@ static void __comedi_buf_alloc(struct comedi_device *dev, if (!bm) return; - async->buf_map = bm; kref_init(&bm->refcount); + spin_lock_irqsave(&s->spin_lock, flags); + async->buf_map = bm; + spin_unlock_irqrestore(&s->spin_lock, flags); bm->dma_dir = s->async_dma_dir; if (bm->dma_dir != DMA_NONE) /* Need ref to hardware device to free buffer later. */ @@ -127,7 +135,9 @@ static void __comedi_buf_alloc(struct comedi_device *dev, pages[i] = virt_to_page(buf->virt_addr); } + spin_lock_irqsave(&s->spin_lock, flags); bm->n_pages = i; + spin_unlock_irqrestore(&s->spin_lock, flags); /* vmap the prealloc_buf if all the pages were allocated */ if (i == n_pages) @@ -150,6 +160,29 @@ int comedi_buf_map_put(struct comedi_buf_map *bm) return 1; } +/* returns s->async->buf_map and increments its kref refcount */ +struct comedi_buf_map * +comedi_buf_map_from_subdev_get(struct comedi_subdevice *s) +{ + struct comedi_async *async = s->async; + struct comedi_buf_map *bm = NULL; + unsigned long flags; + + if (!async) + return NULL; + + spin_lock_irqsave(&s->spin_lock, flags); + bm = async->buf_map; + /* only want it if buffer pages allocated */ + if (bm && bm->n_pages) + comedi_buf_map_get(bm); + else + bm = NULL; + spin_unlock_irqrestore(&s->spin_lock, flags); + + return bm; +} + bool comedi_buf_is_mmapped(struct comedi_async *async) { struct comedi_buf_map *bm = async->buf_map; |