On Wed, Oct 14, 2020 at 09:15:16AM -0700, Jianxin Xiong wrote:
> 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;
> +
Maybe you want to put the explanation why we have to first get the mapping
and then wait on it here as a comment, since that's rather non-obvious for
non-gpu people.
Either way I think the dma-buf side of this looks good now, both the map
and unmap side.
Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> + 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
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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