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path: root/drivers/infiniband/core/umem_dmabuf.c
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Diffstat (limited to 'drivers/infiniband/core/umem_dmabuf.c')
-rw-r--r--drivers/infiniband/core/umem_dmabuf.c174
1 files changed, 174 insertions, 0 deletions
diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
new file mode 100644
index 000000000000..f9b5162d9260
--- /dev/null
+++ b/drivers/infiniband/core/umem_dmabuf.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+/*
+ * Copyright (c) 2020 Intel Corporation. All rights reserved.
+ */
+
+#include <linux/dma-buf.h>
+#include <linux/dma-resv.h>
+#include <linux/dma-mapping.h>
+
+#include "uverbs.h"
+
+int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
+{
+ struct sg_table *sgt;
+ struct scatterlist *sg;
+ struct dma_fence *fence;
+ unsigned long start, end, cur = 0;
+ unsigned int nmap = 0;
+ int i;
+
+ dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
+
+ if (umem_dmabuf->sgt)
+ goto wait_fence;
+
+ sgt = dma_buf_map_attachment(umem_dmabuf->attach, DMA_BIDIRECTIONAL);
+ if (IS_ERR(sgt))
+ return PTR_ERR(sgt);
+
+ /* modify the sg list in-place to match umem address and length */
+
+ start = ALIGN_DOWN(umem_dmabuf->umem.address, PAGE_SIZE);
+ end = ALIGN(umem_dmabuf->umem.address + umem_dmabuf->umem.length,
+ PAGE_SIZE);
+ for_each_sgtable_dma_sg(sgt, sg, i) {
+ if (start < cur + sg_dma_len(sg) && cur < end)
+ nmap++;
+ if (cur <= start && start < cur + sg_dma_len(sg)) {
+ unsigned long offset = start - cur;
+
+ umem_dmabuf->first_sg = sg;
+ umem_dmabuf->first_sg_offset = offset;
+ sg_dma_address(sg) += offset;
+ sg_dma_len(sg) -= offset;
+ cur += offset;
+ }
+ if (cur < end && end <= cur + sg_dma_len(sg)) {
+ unsigned long trim = cur + sg_dma_len(sg) - end;
+
+ umem_dmabuf->last_sg = sg;
+ umem_dmabuf->last_sg_trim = trim;
+ sg_dma_len(sg) -= trim;
+ break;
+ }
+ cur += sg_dma_len(sg);
+ }
+
+ umem_dmabuf->umem.sg_head.sgl = umem_dmabuf->first_sg;
+ umem_dmabuf->umem.sg_head.nents = nmap;
+ umem_dmabuf->umem.nmap = nmap;
+ umem_dmabuf->sgt = sgt;
+
+wait_fence:
+ /*
+ * Although the sg list is valid now, the content of the pages
+ * may be not up-to-date. Wait for the exporter to finish
+ * the migration.
+ */
+ fence = dma_resv_get_excl(umem_dmabuf->attach->dmabuf->resv);
+ if (fence)
+ return dma_fence_wait(fence, false);
+
+ return 0;
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_map_pages);
+
+void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf)
+{
+ dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
+
+ if (!umem_dmabuf->sgt)
+ return;
+
+ /* retore the original sg list */
+ if (umem_dmabuf->first_sg) {
+ sg_dma_address(umem_dmabuf->first_sg) -=
+ umem_dmabuf->first_sg_offset;
+ sg_dma_len(umem_dmabuf->first_sg) +=
+ umem_dmabuf->first_sg_offset;
+ umem_dmabuf->first_sg = NULL;
+ umem_dmabuf->first_sg_offset = 0;
+ }
+ if (umem_dmabuf->last_sg) {
+ sg_dma_len(umem_dmabuf->last_sg) +=
+ umem_dmabuf->last_sg_trim;
+ umem_dmabuf->last_sg = NULL;
+ umem_dmabuf->last_sg_trim = 0;
+ }
+
+ dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt,
+ DMA_BIDIRECTIONAL);
+
+ umem_dmabuf->sgt = NULL;
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_unmap_pages);
+
+struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
+ unsigned long offset, size_t size,
+ int fd, int access,
+ const struct dma_buf_attach_ops *ops)
+{
+ struct dma_buf *dmabuf;
+ struct ib_umem_dmabuf *umem_dmabuf;
+ struct ib_umem *umem;
+ unsigned long end;
+ struct ib_umem_dmabuf *ret = ERR_PTR(-EINVAL);
+
+ if (check_add_overflow(offset, (unsigned long)size, &end))
+ return ret;
+
+ if (unlikely(!ops || !ops->move_notify))
+ return ret;
+
+ dmabuf = dma_buf_get(fd);
+ if (IS_ERR(dmabuf))
+ return ERR_CAST(dmabuf);
+
+ if (dmabuf->size < end)
+ goto out_release_dmabuf;
+
+ umem_dmabuf = kzalloc(sizeof(*umem_dmabuf), GFP_KERNEL);
+ if (!umem_dmabuf) {
+ ret = ERR_PTR(-ENOMEM);
+ goto out_release_dmabuf;
+ }
+
+ umem = &umem_dmabuf->umem;
+ umem->ibdev = device;
+ umem->length = size;
+ umem->address = offset;
+ umem->writable = ib_access_writable(access);
+ umem->is_dmabuf = 1;
+
+ if (!ib_umem_num_pages(umem))
+ goto out_free_umem;
+
+ umem_dmabuf->attach = dma_buf_dynamic_attach(
+ dmabuf,
+ device->dma_device,
+ ops,
+ umem_dmabuf);
+ if (IS_ERR(umem_dmabuf->attach)) {
+ ret = ERR_CAST(umem_dmabuf->attach);
+ goto out_free_umem;
+ }
+ return umem_dmabuf;
+
+out_free_umem:
+ kfree(umem_dmabuf);
+
+out_release_dmabuf:
+ dma_buf_put(dmabuf);
+ return ret;
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_get);
+
+void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf)
+{
+ struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
+
+ dma_buf_detach(dmabuf, umem_dmabuf->attach);
+ dma_buf_put(dmabuf);
+ kfree(umem_dmabuf);
+}