diff options
Diffstat (limited to 'drivers/staging/comedi/comedi_buf.c')
-rw-r--r-- | drivers/staging/comedi/comedi_buf.c | 99 |
1 files changed, 69 insertions, 30 deletions
diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c index 4e26bd7..924fce9 100644 --- a/drivers/staging/comedi/comedi_buf.c +++ b/drivers/staging/comedi/comedi_buf.c @@ -16,6 +16,7 @@ */ #include <linux/vmalloc.h> +#include <linux/slab.h> #include "comedidev.h" #include "comedi_internal.h" @@ -26,31 +27,21 @@ #define COMEDI_PAGE_PROTECTION PAGE_KERNEL #endif -static void __comedi_buf_free(struct comedi_device *dev, - struct comedi_subdevice *s, - unsigned n_pages) +static void comedi_buf_map_kref_release(struct kref *kref) { - struct comedi_async *async = s->async; + struct comedi_buf_map *bm = + container_of(kref, struct comedi_buf_map, refcount); struct comedi_buf_page *buf; - unsigned i; - - if (async->prealloc_buf) { - vunmap(async->prealloc_buf); - async->prealloc_buf = NULL; - async->prealloc_bufsz = 0; - } + unsigned int i; - if (!async->buf_page_list) - return; - - for (i = 0; i < n_pages; ++i) { - buf = &async->buf_page_list[i]; - if (buf->virt_addr) { + if (bm->page_list) { + for (i = 0; i < bm->n_pages; i++) { + buf = &bm->page_list[i]; clear_bit(PG_reserved, &(virt_to_page(buf->virt_addr)->flags)); - if (s->async_dma_dir != DMA_NONE) { + if (bm->dma_dir != DMA_NONE) { #ifdef CONFIG_HAS_DMA - dma_free_coherent(dev->hw_dev, + dma_free_coherent(bm->dma_hw_dev, PAGE_SIZE, buf->virt_addr, buf->dma_addr); @@ -59,10 +50,26 @@ static void __comedi_buf_free(struct comedi_device *dev, free_page((unsigned long)buf->virt_addr); } } + vfree(bm->page_list); } - vfree(async->buf_page_list); - async->buf_page_list = NULL; - async->n_buf_pages = 0; + if (bm->dma_dir != DMA_NONE) + put_device(bm->dma_hw_dev); + kfree(bm); +} + +static void __comedi_buf_free(struct comedi_device *dev, + struct comedi_subdevice *s) +{ + struct comedi_async *async = s->async; + + if (async->prealloc_buf) { + vunmap(async->prealloc_buf); + async->prealloc_buf = NULL; + async->prealloc_bufsz = 0; + } + + comedi_buf_map_put(async->buf_map); + async->buf_map = NULL; } static void __comedi_buf_alloc(struct comedi_device *dev, @@ -71,6 +78,7 @@ static void __comedi_buf_alloc(struct comedi_device *dev, { struct comedi_async *async = s->async; struct page **pages = NULL; + struct comedi_buf_map *bm; struct comedi_buf_page *buf; unsigned i; @@ -80,18 +88,29 @@ static void __comedi_buf_alloc(struct comedi_device *dev, return; } - async->buf_page_list = vzalloc(sizeof(*buf) * n_pages); - if (async->buf_page_list) + bm = kzalloc(sizeof(*async->buf_map), GFP_KERNEL); + if (!bm) + return; + + async->buf_map = bm; + kref_init(&bm->refcount); + bm->dma_dir = s->async_dma_dir; + if (bm->dma_dir != DMA_NONE) + /* Need ref to hardware device to free buffer later. */ + bm->dma_hw_dev = get_device(dev->hw_dev); + + bm->page_list = vzalloc(sizeof(*buf) * n_pages); + if (bm->page_list) pages = vmalloc(sizeof(struct page *) * n_pages); if (!pages) return; for (i = 0; i < n_pages; i++) { - buf = &async->buf_page_list[i]; - if (s->async_dma_dir != DMA_NONE) + buf = &bm->page_list[i]; + if (bm->dma_dir != DMA_NONE) #ifdef CONFIG_HAS_DMA - buf->virt_addr = dma_alloc_coherent(dev->hw_dev, + buf->virt_addr = dma_alloc_coherent(bm->dma_hw_dev, PAGE_SIZE, &buf->dma_addr, GFP_KERNEL | @@ -108,6 +127,7 @@ static void __comedi_buf_alloc(struct comedi_device *dev, pages[i] = virt_to_page(buf->virt_addr); } + bm->n_pages = i; /* vmap the prealloc_buf if all the pages were allocated */ if (i == n_pages) @@ -117,6 +137,26 @@ static void __comedi_buf_alloc(struct comedi_device *dev, vfree(pages); } +void comedi_buf_map_get(struct comedi_buf_map *bm) +{ + if (bm) + kref_get(&bm->refcount); +} + +int comedi_buf_map_put(struct comedi_buf_map *bm) +{ + if (bm) + return kref_put(&bm->refcount, comedi_buf_map_kref_release); + return 1; +} + +bool comedi_buf_is_mmapped(struct comedi_async *async) +{ + struct comedi_buf_map *bm = async->buf_map; + + return bm && (atomic_read(&bm->refcount.refcount) > 1); +} + int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s, unsigned long new_size) { @@ -130,7 +170,7 @@ int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s, return 0; /* deallocate old buffer */ - __comedi_buf_free(dev, s, async->n_buf_pages); + __comedi_buf_free(dev, s); /* allocate new buffer */ if (new_size) { @@ -140,10 +180,9 @@ int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s, if (!async->prealloc_buf) { /* allocation failed */ - __comedi_buf_free(dev, s, n_pages); + __comedi_buf_free(dev, s); return -ENOMEM; } - async->n_buf_pages = n_pages; } async->prealloc_bufsz = new_size; |