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@xxxxxxxxx>
Reviewed-by: Sean Hefty <sean.hefty@xxxxxxxxx>
Acked-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
Acked-by: Christian Koenig <christian.koenig@xxxxxxx>
---
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
