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91 lines
2.5 KiB
Diff
91 lines
2.5 KiB
Diff
From 9dc454ebc4380cd90c24a3c224bb0ac7b3d9cc29 Mon Sep 17 00:00:00 2001
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From: Gurchetan Singh <gurchetansingh@chromium.org>
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Date: Mon, 2 Dec 2019 17:36:27 -0800
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Subject: [PATCH] udmabuf: implement begin_cpu_access/end_cpu_access
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hooks
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Commit 284562e1f34874e267d4f499362c3816f8f6bc3f upstream.
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With the misc device, we should end up using the result of
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get_arch_dma_ops(..) or dma-direct ops.
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This can allow us to have WC mappings in the guest after
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synchronization.
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Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
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Link: http://patchwork.freedesktop.org/patch/msgid/20191203013627.85991-4-gurchetansingh@chromium.org
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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---
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drivers/dma-buf/udmabuf.c | 39 +++++++++++++++++++++++++++++++++++++++
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1 file changed, 39 insertions(+)
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--- a/drivers/dma-buf/udmabuf.c
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+++ b/drivers/dma-buf/udmabuf.c
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@@ -18,6 +18,7 @@ static const size_t size_limit_mb = 64;
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struct udmabuf {
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pgoff_t pagecount;
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struct page **pages;
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+ struct sg_table *sg;
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struct miscdevice *device;
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};
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@@ -98,20 +99,58 @@ static void unmap_udmabuf(struct dma_buf
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static void release_udmabuf(struct dma_buf *buf)
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{
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struct udmabuf *ubuf = buf->priv;
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+ struct device *dev = ubuf->device->this_device;
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pgoff_t pg;
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+ if (ubuf->sg)
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+ put_sg_table(dev, ubuf->sg, DMA_BIDIRECTIONAL);
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+
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for (pg = 0; pg < ubuf->pagecount; pg++)
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put_page(ubuf->pages[pg]);
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kfree(ubuf->pages);
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kfree(ubuf);
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}
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+static int begin_cpu_udmabuf(struct dma_buf *buf,
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+ enum dma_data_direction direction)
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+{
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+ struct udmabuf *ubuf = buf->priv;
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+ struct device *dev = ubuf->device->this_device;
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+
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+ if (!ubuf->sg) {
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+ ubuf->sg = get_sg_table(dev, buf, direction);
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+ if (IS_ERR(ubuf->sg))
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+ return PTR_ERR(ubuf->sg);
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+ } else {
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+ dma_sync_sg_for_device(dev, ubuf->sg->sgl,
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+ ubuf->sg->nents,
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+ direction);
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+ }
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+
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+ return 0;
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+}
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+
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+static int end_cpu_udmabuf(struct dma_buf *buf,
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+ enum dma_data_direction direction)
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+{
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+ struct udmabuf *ubuf = buf->priv;
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+ struct device *dev = ubuf->device->this_device;
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+
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+ if (!ubuf->sg)
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+ return -EINVAL;
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+
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+ dma_sync_sg_for_cpu(dev, ubuf->sg->sgl, ubuf->sg->nents, direction);
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+ return 0;
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+}
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+
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static const struct dma_buf_ops udmabuf_ops = {
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.cache_sgt_mapping = true,
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.map_dma_buf = map_udmabuf,
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.unmap_dma_buf = unmap_udmabuf,
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.release = release_udmabuf,
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.mmap = mmap_udmabuf,
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+ .begin_cpu_access = begin_cpu_udmabuf,
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+ .end_cpu_access = end_cpu_udmabuf,
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};
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#define SEALS_WANTED (F_SEAL_SHRINK)
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