From 48675044f980bf51aa4058714796ad5dfda8423d Mon Sep 17 00:00:00 2001 From: Hyesoo Yu Date: Fri, 20 Mar 2020 18:54:00 +0900 Subject: [PATCH] ANDROID: staging: ion: optimize cache operation for non-cached buffer The non-cached ion buffer is flushed when allocated. And then, that is is always mapped as non-cached after allocation. In the absence of caching, cache maintenance operations become unnecessary. However dma_buf_ops tries to maintain cache coherency for non-cached buffer on begin[end]_cpu_access and map[unmap]_dma_buf functions. It creates unnecessary overhead, so let's remove it. Bug: 151775080 Signed-off-by: Hyesoo Yu Change-Id: I168117c7002aec7930c84168d15816a09750b7d8 Signed-off-by: Hridya Valsaraju (cherry picked from commit 2c3b4cba8ab38d7eb9f474c78f9b4c70867bf71d) Signed-off-by: Hridya Valsaraju --- drivers/staging/android/ion/ion_dma_buf.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/staging/android/ion/ion_dma_buf.c b/drivers/staging/android/ion/ion_dma_buf.c index ed2136c50693..177baab4ad48 100644 --- a/drivers/staging/android/ion/ion_dma_buf.c +++ b/drivers/staging/android/ion/ion_dma_buf.c @@ -105,6 +105,7 @@ static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment, struct ion_heap *heap = buffer->heap; struct ion_dma_buf_attachment *a; struct sg_table *table; + unsigned long attrs = attachment->dma_map_attrs; if (heap->buf_ops.map_dma_buf) return heap->buf_ops.map_dma_buf(attachment, direction); @@ -112,8 +113,11 @@ static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment, a = attachment->priv; table = a->table; + if (!(buffer->flags & ION_FLAG_CACHED)) + attrs |= DMA_ATTR_SKIP_CPU_SYNC; + if (!dma_map_sg_attrs(attachment->dev, table->sgl, table->nents, - direction, attachment->dma_map_attrs)) + direction, attrs)) return ERR_PTR(-ENOMEM); a->mapped = true; @@ -128,6 +132,7 @@ static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment, struct ion_buffer *buffer = attachment->dmabuf->priv; struct ion_heap *heap = buffer->heap; struct ion_dma_buf_attachment *a = attachment->priv; + unsigned long attrs = attachment->dma_map_attrs; a->mapped = false; @@ -135,8 +140,11 @@ static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment, return heap->buf_ops.unmap_dma_buf(attachment, table, direction); + if (!(buffer->flags & ION_FLAG_CACHED)) + attrs |= DMA_ATTR_SKIP_CPU_SYNC; + dma_unmap_sg_attrs(attachment->dev, table->sgl, table->nents, - direction, attachment->dma_map_attrs); + direction, attrs); } static void ion_dma_buf_release(struct dma_buf *dmabuf) @@ -174,6 +182,9 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, goto unlock; } + if (!(buffer->flags & ION_FLAG_CACHED)) + goto unlock; + list_for_each_entry(a, &buffer->attachments, list) { if (!a->mapped) continue; @@ -218,12 +229,17 @@ static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf, mutex_lock(&buffer->lock); ion_buffer_kmap_put(buffer); + + if (!(buffer->flags & ION_FLAG_CACHED)) + goto unlock; + list_for_each_entry(a, &buffer->attachments, list) { if (!a->mapped) continue; dma_sync_sg_for_device(a->dev, a->table->sgl, a->table->nents, direction); } +unlock: mutex_unlock(&buffer->lock); return 0;