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* [PATCH v4 1/5] RDMA/umem: Support importing dma-buf as user memory region
@ 2020-10-14 16:15 Jianxin Xiong
  2020-10-15  0:12 ` kernel test robot
  2020-10-15 16:06 ` Daniel Vetter
  0 siblings, 2 replies; 3+ messages in thread
From: Jianxin Xiong @ 2020-10-14 16:15 UTC (permalink / raw)
  To: linux-rdma, dri-devel
  Cc: Jianxin Xiong, Doug Ledford, Jason Gunthorpe, Leon Romanovsky,
	Sumit Semwal, Christian Koenig, Daniel Vetter

Dma-buf is a standard cross-driver buffer sharing mechanism that can be
used to support peer-to-peer access from RDMA devices.

Device memory exported via dma-buf is associated with a file descriptor.
This is passed to the user space as a property associated with the
buffer allocation. When the buffer is registered as a memory region,
the file descriptor is passed to the RDMA driver along with other
parameters.

Implement the common code for importing dma-buf object and mapping
dma-buf pages.

Signed-off-by: Jianxin Xiong <jianxin.xiong@intel.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Acked-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Acked-by: Christian Koenig <christian.koenig@amd.com>
---
 drivers/infiniband/core/Makefile      |   2 +-
 drivers/infiniband/core/umem.c        |   4 +
 drivers/infiniband/core/umem_dmabuf.c | 200 ++++++++++++++++++++++++++++++++++
 drivers/infiniband/core/umem_dmabuf.h |  11 ++
 include/rdma/ib_umem.h                |  32 +++++-
 5 files changed, 247 insertions(+), 2 deletions(-)
 create mode 100644 drivers/infiniband/core/umem_dmabuf.c
 create mode 100644 drivers/infiniband/core/umem_dmabuf.h

diff --git a/drivers/infiniband/core/Makefile b/drivers/infiniband/core/Makefile
index ccf2670..8ab4eea 100644
--- a/drivers/infiniband/core/Makefile
+++ b/drivers/infiniband/core/Makefile
@@ -40,5 +40,5 @@ ib_uverbs-y :=			uverbs_main.o uverbs_cmd.o uverbs_marshall.o \
 				uverbs_std_types_srq.o \
 				uverbs_std_types_wq.o \
 				uverbs_std_types_qp.o
-ib_uverbs-$(CONFIG_INFINIBAND_USER_MEM) += umem.o
+ib_uverbs-$(CONFIG_INFINIBAND_USER_MEM) += umem.o umem_dmabuf.o
 ib_uverbs-$(CONFIG_INFINIBAND_ON_DEMAND_PAGING) += umem_odp.o
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index e9fecbd..8c608a5 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -2,6 +2,7 @@
  * Copyright (c) 2005 Topspin Communications.  All rights reserved.
  * Copyright (c) 2005 Cisco Systems.  All rights reserved.
  * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2020 Intel Corporation. All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
@@ -43,6 +44,7 @@
 #include <rdma/ib_umem_odp.h>
 
 #include "uverbs.h"
+#include "umem_dmabuf.h"
 
 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
 {
@@ -269,6 +271,8 @@ void ib_umem_release(struct ib_umem *umem)
 {
 	if (!umem)
 		return;
+	if (umem->is_dmabuf)
+		return ib_umem_dmabuf_release(umem);
 	if (umem->is_odp)
 		return ib_umem_odp_release(to_ib_umem_odp(umem));
 
diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
new file mode 100644
index 0000000..4f2303e
--- /dev/null
+++ b/drivers/infiniband/core/umem_dmabuf.c
@@ -0,0 +1,200 @@
+// 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"
+
+struct ib_umem_dmabuf {
+	struct ib_umem umem;
+	struct dma_buf_attachment *attach;
+	struct sg_table *sgt;
+	const struct ib_umem_dmabuf_ops *ops;
+	void *device_context;
+	struct work_struct work;
+};
+
+static inline struct ib_umem_dmabuf *to_ib_umem_dmabuf(struct ib_umem *umem)
+{
+	return container_of(umem, struct ib_umem_dmabuf, umem);
+}
+
+int ib_umem_dmabuf_map_pages(struct ib_umem *umem, bool first)
+{
+	struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(umem);
+	struct sg_table *sgt;
+	struct dma_fence *fence;
+	int err;
+
+	dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL);
+
+	sgt = dma_buf_map_attachment(umem_dmabuf->attach,
+				     DMA_BIDIRECTIONAL);
+
+	if (IS_ERR(sgt)) {
+		dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
+		return PTR_ERR(sgt);
+	}
+
+	umem_dmabuf->umem.sg_head = *sgt;
+	umem_dmabuf->umem.nmap = sgt->nents;
+	umem_dmabuf->sgt = sgt;
+
+	fence = dma_resv_get_excl(umem_dmabuf->attach->dmabuf->resv);
+	if (fence)
+		dma_fence_wait(fence, false);
+
+	if (first)
+		err = umem_dmabuf->ops->init(umem,
+					     umem_dmabuf->device_context);
+	else
+		err = umem_dmabuf->ops->update(umem,
+					       umem_dmabuf->device_context);
+
+	dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
+	return err;
+}
+
+int ib_umem_dmabuf_init_mapping(struct ib_umem *umem, void *device_context)
+{
+	struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(umem);
+
+	umem_dmabuf->device_context = device_context;
+	return ib_umem_dmabuf_map_pages(umem, true);
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_init_mapping);
+
+bool ib_umem_dmabuf_mapping_ready(struct ib_umem *umem)
+{
+	struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(umem);
+	bool ret;
+
+	dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL);
+	ret = !!umem_dmabuf->sgt;
+	dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
+	return ret;
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_mapping_ready);
+
+static void ib_umem_dmabuf_unmap_pages(struct ib_umem *umem, bool do_invalidate)
+{
+	struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(umem);
+
+	dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
+
+	if (!umem_dmabuf->sgt)
+		return;
+
+	if (do_invalidate)
+		umem_dmabuf->ops->invalidate(umem, umem_dmabuf->device_context);
+
+	dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt,
+				 DMA_BIDIRECTIONAL);
+	umem_dmabuf->sgt = NULL;
+}
+
+static void ib_umem_dmabuf_work(struct work_struct *work)
+{
+	struct ib_umem_dmabuf *umem_dmabuf;
+	int ret;
+
+	umem_dmabuf = container_of(work, struct ib_umem_dmabuf, work);
+	ret = ib_umem_dmabuf_map_pages(&umem_dmabuf->umem, false);
+	if (ret)
+		pr_debug("%s: failed to update dmabuf mapping, error %d\n",
+			 __func__, ret);
+}
+
+static void ib_umem_dmabuf_invalidate_cb(struct dma_buf_attachment *attach)
+{
+	struct ib_umem_dmabuf *umem_dmabuf = attach->importer_priv;
+
+	dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
+
+	ib_umem_dmabuf_unmap_pages(&umem_dmabuf->umem, true);
+	queue_work(ib_wq, &umem_dmabuf->work);
+}
+
+static struct dma_buf_attach_ops ib_umem_dmabuf_attach_ops = {
+	.allow_peer2peer = 1,
+	.move_notify = ib_umem_dmabuf_invalidate_cb,
+};
+
+struct ib_umem *ib_umem_dmabuf_get(struct ib_device *device,
+				   unsigned long addr, size_t size,
+				   int dmabuf_fd, int access,
+				   const struct ib_umem_dmabuf_ops *ops)
+{
+	struct dma_buf *dmabuf;
+	struct ib_umem_dmabuf *umem_dmabuf;
+	struct ib_umem *umem;
+	unsigned long end;
+	long ret;
+
+	if (check_add_overflow(addr, size, &end))
+		return ERR_PTR(-EINVAL);
+
+	if (unlikely(PAGE_ALIGN(end) < PAGE_SIZE))
+		return ERR_PTR(-EINVAL);
+
+	if (unlikely(!ops || !ops->invalidate || !ops->update))
+		return ERR_PTR(-EINVAL);
+
+	umem_dmabuf = kzalloc(sizeof(*umem_dmabuf), GFP_KERNEL);
+	if (!umem_dmabuf)
+		return ERR_PTR(-ENOMEM);
+
+	umem_dmabuf->ops = ops;
+	INIT_WORK(&umem_dmabuf->work, ib_umem_dmabuf_work);
+
+	umem = &umem_dmabuf->umem;
+	umem->ibdev = device;
+	umem->length = size;
+	umem->address = addr;
+	umem->writable = ib_access_writable(access);
+	umem->is_dmabuf = 1;
+
+	dmabuf = dma_buf_get(dmabuf_fd);
+	if (IS_ERR(dmabuf)) {
+		ret = PTR_ERR(dmabuf);
+		goto out_free_umem;
+	}
+
+	umem_dmabuf->attach = dma_buf_dynamic_attach(
+					dmabuf,
+					device->dma_device,
+					&ib_umem_dmabuf_attach_ops,
+					umem_dmabuf);
+	if (IS_ERR(umem_dmabuf->attach)) {
+		ret = PTR_ERR(umem_dmabuf->attach);
+		goto out_release_dmabuf;
+	}
+
+	return umem;
+
+out_release_dmabuf:
+	dma_buf_put(dmabuf);
+
+out_free_umem:
+	kfree(umem_dmabuf);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_get);
+
+void ib_umem_dmabuf_release(struct ib_umem *umem)
+{
+	struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(umem);
+	struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
+
+	dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL);
+	ib_umem_dmabuf_unmap_pages(umem, false);
+	dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
+
+	dma_buf_detach(dmabuf, umem_dmabuf->attach);
+	dma_buf_put(dmabuf);
+	kfree(umem_dmabuf);
+}
diff --git a/drivers/infiniband/core/umem_dmabuf.h b/drivers/infiniband/core/umem_dmabuf.h
new file mode 100644
index 0000000..485f653
--- /dev/null
+++ b/drivers/infiniband/core/umem_dmabuf.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/*
+ * Copyright (c) 2020 Intel Corporation. All rights reserved.
+ */
+
+#ifndef UMEM_DMABUF_H
+#define UMEM_DMABUF_H
+
+void ib_umem_dmabuf_release(struct ib_umem *umem);
+
+#endif /* UMEM_DMABUF_H */
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 7059750..fac8553 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
 /*
  * Copyright (c) 2007 Cisco Systems.  All rights reserved.
+ * Copyright (c) 2020 Intel Corporation.  All rights reserved.
  */
 
 #ifndef IB_UMEM_H
@@ -22,12 +23,19 @@ struct ib_umem {
 	unsigned long		address;
 	u32 writable : 1;
 	u32 is_odp : 1;
+	u32 is_dmabuf : 1;
 	struct work_struct	work;
 	struct sg_table sg_head;
 	int             nmap;
 	unsigned int    sg_nents;
 };
 
+struct ib_umem_dmabuf_ops {
+	int	(*init)(struct ib_umem *umem, void *context);
+	int	(*update)(struct ib_umem *umem, void *context);
+	int	(*invalidate)(struct ib_umem *umem, void *context);
+};
+
 /* Returns the offset of the umem start relative to the first page. */
 static inline int ib_umem_offset(struct ib_umem *umem)
 {
@@ -79,6 +87,12 @@ int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
 unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
 				     unsigned long pgsz_bitmap,
 				     unsigned long virt);
+struct ib_umem *ib_umem_dmabuf_get(struct ib_device *device,
+				   unsigned long addr, size_t size,
+				   int dmabuf_fd, int access,
+				   const struct ib_umem_dmabuf_ops *ops);
+int ib_umem_dmabuf_init_mapping(struct ib_umem *umem, void *device_context);
+bool ib_umem_dmabuf_mapping_ready(struct ib_umem *umem);
 
 #else /* CONFIG_INFINIBAND_USER_MEM */
 
@@ -101,7 +115,23 @@ static inline unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
 {
 	return 0;
 }
+static inline struct ib_umem *ib_umem_dmabuf_get(struct ib_device *device,
+						 unsigned long addr,
+						 size_t size, int dmabuf_fd,
+						 int access,
+						 struct ib_umem_dmabuf_ops *ops)
+{
+	return ERR_PTR(-EINVAL);
+}
+static inline int ib_umem_dmabuf_init_mapping(struct ib_umem *umem,
+					      void *device_context)
+{
+	return -EINVAL;
+}
+static inline bool ib_umem_dmabuf_mapping_ready(struct ib_umem *umem)
+{
+	return false;
+}
 
 #endif /* CONFIG_INFINIBAND_USER_MEM */
-
 #endif /* IB_UMEM_H */
-- 
1.8.3.1


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2020-10-14 16:15 [PATCH v4 1/5] RDMA/umem: Support importing dma-buf as user memory region Jianxin Xiong
2020-10-15  0:12 ` kernel test robot
2020-10-15 16:06 ` Daniel Vetter

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