On 12/24/18 12:19 AM, Qing Xia wrote:
Now, as Google's user guide, if userspace need clean ION buffer's cache, they should call ioctl(fd, DMA_BUF_IOCTL_SYNC, sync). Then we found that ion_dma_buf_begin_cpu_access/ion_dma_buf_end_cpu_access will do ION buffer's map_kernel, it's not necessary. And if usersapce only need clean cache, they will call ion_dma_buf_end_cpu_access by dmabuf's ioctl, ION buffer's kmap_cnt will be wrong value -1, then driver could not get right kernel vaddr by dma_buf_kmap.
The problem is this subtly violates how dma_buf is supposed to work. All setup is supposed to happen in begin_cpu_access. I agree calling map kernel each time isn't great but I think this needs to be worked out with dma_buf. Thanks, Laura
Signed-off-by: Qing Xia <saberlily....@hisilicon.com> --- drivers/staging/android/ion/ion.c | 46 ++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 25 deletions(-) diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c index 9907332..f7e2812 100644 --- a/drivers/staging/android/ion/ion.c +++ b/drivers/staging/android/ion/ion.c @@ -303,45 +303,47 @@ static void ion_dma_buf_release(struct dma_buf *dmabuf) static void *ion_dma_buf_kmap(struct dma_buf *dmabuf, unsigned long offset) { struct ion_buffer *buffer = dmabuf->priv; + void *vaddr;- return buffer->vaddr + offset * PAGE_SIZE;+ if (buffer->heap->ops->map_kernel) { + mutex_lock(&buffer->lock); + vaddr = ion_buffer_kmap_get(buffer); + mutex_unlock(&buffer->lock); + if (IS_ERR(vaddr)) + return vaddr; + + return vaddr + offset * PAGE_SIZE; + } + + return NULL; }static void ion_dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long offset,void *ptr) { + struct ion_buffer *buffer = dmabuf->priv; + + if (buffer->heap->ops->map_kernel) { + mutex_lock(&buffer->lock); + ion_buffer_kmap_put(buffer); + mutex_unlock(&buffer->lock); + } }static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,enum dma_data_direction direction) { struct ion_buffer *buffer = dmabuf->priv; - void *vaddr; struct ion_dma_buf_attachment *a; - int ret = 0; - - /* - * TODO: Move this elsewhere because we don't always need a vaddr - */ - if (buffer->heap->ops->map_kernel) { - mutex_lock(&buffer->lock); - vaddr = ion_buffer_kmap_get(buffer); - if (IS_ERR(vaddr)) { - ret = PTR_ERR(vaddr); - goto unlock; - } - mutex_unlock(&buffer->lock); - }mutex_lock(&buffer->lock);list_for_each_entry(a, &buffer->attachments, list) { dma_sync_sg_for_cpu(a->dev, a->table->sgl, a->table->nents, direction); } - -unlock: mutex_unlock(&buffer->lock); - return ret; + + return 0; }static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf,@@ -350,12 +352,6 @@ static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf, struct ion_buffer *buffer = dmabuf->priv; struct ion_dma_buf_attachment *a;- if (buffer->heap->ops->map_kernel) {- mutex_lock(&buffer->lock); - ion_buffer_kmap_put(buffer); - mutex_unlock(&buffer->lock); - } - mutex_lock(&buffer->lock); list_for_each_entry(a, &buffer->attachments, list) { dma_sync_sg_for_device(a->dev, a->table->sgl, a->table->nents,
_______________________________________________ devel mailing list de...@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
