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>
---
drivers/infiniband/core/Makefile | 2 +-
drivers/infiniband/core/umem.c | 4 +
drivers/infiniband/core/umem_dmabuf.c | 291 ++++++++++++++++++++++++++++++++++
drivers/infiniband/core/umem_dmabuf.h | 14 ++
drivers/infiniband/core/umem_odp.c | 12 ++
include/rdma/ib_umem.h | 19 ++-
6 files changed, 340 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 24cb71a..b8d51a7 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 831bff8..59ec36c 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
@@ -42,6 +43,7 @@
#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)
{
@@ -318,6 +320,8 @@ 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..10ed646
--- /dev/null
+++ b/drivers/infiniband/core/umem_dmabuf.c
@@ -0,0 +1,291 @@
+// 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 <rdma/ib_umem_odp.h>
+
+#include "uverbs.h"
+
+struct ib_umem_dmabuf {
+ struct ib_umem_odp umem_odp;
+ struct dma_buf_attachment *attach;
+ struct sg_table *sgt;
+ atomic_t notifier_seq;
+};
+
+static inline struct ib_umem_dmabuf *to_ib_umem_dmabuf(struct ib_umem *umem)
+{
+ struct ib_umem_odp *umem_odp = to_ib_umem_odp(umem);
+ return container_of(umem_odp, struct ib_umem_dmabuf, umem_odp);
+}
+
+static void ib_umem_dmabuf_invalidate_cb(struct dma_buf_attachment *attach)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = attach->importer_priv;
+ struct ib_umem_odp *umem_odp = &umem_dmabuf->umem_odp;
+ struct mmu_notifier_range range = {};
+ unsigned long current_seq;
+
+ /* no concurrent invalidation due to the dma_resv lock */
+
+ dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
+
+ if (!umem_dmabuf->sgt)
+ return;
+
+ range.start = ib_umem_start(umem_odp);
+ range.end = ib_umem_end(umem_odp);
+ range.flags = MMU_NOTIFIER_RANGE_BLOCKABLE;
+ current_seq = atomic_read(&umem_dmabuf->notifier_seq);
+ umem_odp->notifier.ops->invalidate(&umem_odp->notifier, &range,
+ current_seq);
+
+ atomic_inc(&umem_dmabuf->notifier_seq);
+}
+
+static struct dma_buf_attach_ops ib_umem_dmabuf_attach_ops = {
+ .allow_peer2peer = 1,
+ .move_notify = ib_umem_dmabuf_invalidate_cb,
+};
+
+static inline int ib_umem_dmabuf_init_odp(struct ib_umem_odp *umem_odp)
+{
+ size_t page_size = 1UL << umem_odp->page_shift;
+ unsigned long start;
+ unsigned long end;
+ size_t pages;
+
+ umem_odp->umem.is_odp = 1;
+ mutex_init(&umem_odp->umem_mutex);
+
+ start = ALIGN_DOWN(umem_odp->umem.address, page_size);
+ if (check_add_overflow(umem_odp->umem.address,
+ (unsigned long)umem_odp->umem.length,
+ &end))
+ return -EOVERFLOW;
+ end = ALIGN(end, page_size);
+ if (unlikely(end < page_size))
+ return -EOVERFLOW;
+
+ pages = (end - start) >> umem_odp->page_shift;
+ if (!pages)
+ return -EINVAL;
+
+ /* used for ib_umem_start() & ib_umem_end() */
+ umem_odp->notifier.interval_tree.start = start;
+ umem_odp->notifier.interval_tree.last = end - 1;
+
+ /* umem_odp->page_list is never used for dma-buf */
+
+ umem_odp->dma_list = kvcalloc(
+ pages, sizeof(*umem_odp->dma_list), GFP_KERNEL);
+ if (!umem_odp->dma_list)
+ return -ENOMEM;
+
+ return 0;
+}
+
+struct ib_umem *ib_umem_dmabuf_get(struct ib_device *device,
+ unsigned long addr, size_t size,
+ int dmabuf_fd, int access,
+ const struct mmu_interval_notifier_ops *ops)
+{
+ struct dma_buf *dmabuf;
+ struct ib_umem_dmabuf *umem_dmabuf;
+ struct ib_umem *umem;
+ struct ib_umem_odp *umem_odp;
+ 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);
+
+ umem_dmabuf = kzalloc(sizeof(*umem_dmabuf), GFP_KERNEL);
+ if (!umem_dmabuf)
+ return ERR_PTR(-ENOMEM);
+
+ umem = &umem_dmabuf->umem_odp.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;
+ }
+
+ /* always attach dynamically to pass the allow_peer2peer flag */
+ 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;
+ }
+
+ umem_odp = &umem_dmabuf->umem_odp;
+ umem_odp->page_shift = PAGE_SHIFT;
+ if (access & IB_ACCESS_HUGETLB) {
+ /* don't support huge_tlb at this point */
+ ret = -EINVAL;
+ goto out_detach_dmabuf;
+ }
+
+ ret = ib_umem_dmabuf_init_odp(umem_odp);
+ if (ret)
+ goto out_detach_dmabuf;
+
+ umem_odp->notifier.ops = ops;
+ return umem;
+
+out_detach_dmabuf:
+ dma_buf_detach(dmabuf, umem_dmabuf->attach);
+
+out_release_dmabuf:
+ dma_buf_put(dmabuf);
+
+out_free_umem:
+ kfree(umem_dmabuf);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_get);
+
+unsigned long ib_umem_dmabuf_notifier_read_begin(struct ib_umem_odp *umem_odp)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(&umem_odp->umem);
+
+ return atomic_read(&umem_dmabuf->notifier_seq);
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_notifier_read_begin);
+
+int ib_umem_dmabuf_notifier_read_retry(struct ib_umem_odp *umem_odp,
+ unsigned long current_seq)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(&umem_odp->umem);
+
+ return (atomic_read(&umem_dmabuf->notifier_seq) != current_seq);
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_notifier_read_retry);
+
+int ib_umem_dmabuf_map_pages(struct ib_umem *umem, u64 user_virt, u64 bcnt,
+ u64 access_mask, unsigned long current_seq)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(umem);
+ struct ib_umem_odp *umem_odp = &umem_dmabuf->umem_odp;
+ u64 start, end, addr;
+ int j, k, ret = 0, user_pages, pages, total_pages;
+ unsigned int page_shift;
+ size_t page_size;
+ struct scatterlist *sg;
+ struct sg_table *sgt;
+
+ if (access_mask == 0)
+ return -EINVAL;
+
+ if (user_virt < ib_umem_start(umem_odp) ||
+ user_virt + bcnt > ib_umem_end(umem_odp))
+ return -EFAULT;
+
+ page_shift = umem_odp->page_shift;
+ page_size = 1UL << page_shift;
+ start = ALIGN_DOWN(user_virt, page_size);
+ end = ALIGN(user_virt + bcnt, page_size);
+ user_pages = (end - start) >> page_shift;
+
+ mutex_lock(&umem_odp->umem_mutex);
+
+ /* check for on-ongoing invalidations */
+ if (ib_umem_dmabuf_notifier_read_retry(umem_odp, current_seq)) {
+ ret = -EAGAIN;
+ goto out;
+ }
+
+ ret = user_pages;
+ if (umem_dmabuf->sgt)
+ goto out;
+
+ dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL);
+ sgt = dma_buf_map_attachment(umem_dmabuf->attach,
+ DMA_BIDIRECTIONAL);
+ dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
+
+ if (IS_ERR(sgt)) {
+ ret = PTR_ERR(sgt);
+ goto out;
+ }
+
+ umem->sg_head = *sgt;
+ umem->nmap = sgt->nents;
+ umem_dmabuf->sgt = sgt;
+
+ k = 0;
+ total_pages = ib_umem_odp_num_pages(umem_odp);
+ for_each_sg(umem->sg_head.sgl, sg, umem->sg_head.nents, j) {
+ addr = sg_dma_address(sg);
+ pages = sg_dma_len(sg) >> page_shift;
+ while (pages > 0 && k < total_pages) {
+ umem_odp->dma_list[k++] = addr | access_mask;
+ umem_odp->npages++;
+ addr += page_size;
+ pages--;
+ }
+ }
+
+ WARN_ON(k != total_pages);
+
+out:
+ mutex_unlock(&umem_odp->umem_mutex);
+ return ret;
+}
+
+void ib_umem_dmabuf_unmap_pages(struct ib_umem *umem)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(umem);
+ struct ib_umem_odp *umem_odp = &umem_dmabuf->umem_odp;
+ int npages = ib_umem_odp_num_pages(umem_odp);
+ int i;
+
+ lockdep_assert_held(&umem_odp->umem_mutex);
+ dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
+
+ if (!umem_dmabuf->sgt)
+ return;
+
+ dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt,
+ DMA_BIDIRECTIONAL);
+
+ umem_dmabuf->sgt = NULL;
+
+ for (i = 0; i < npages; i++)
+ umem_odp->dma_list[i] = 0;
+ umem_odp->npages = 0;
+}
+
+void ib_umem_dmabuf_release(struct ib_umem *umem)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(umem);
+ struct ib_umem_odp *umem_odp = &umem_dmabuf->umem_odp;
+ struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
+
+ mutex_lock(&umem_odp->umem_mutex);
+ dma_resv_lock(umem_dmabuf->attach->dmabuf->resv, NULL);
+ ib_umem_dmabuf_unmap_pages(umem);
+ dma_resv_unlock(umem_dmabuf->attach->dmabuf->resv);
+ mutex_unlock(&umem_odp->umem_mutex);
+ kvfree(umem_odp->dma_list);
+ 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..b9378bd
--- /dev/null
+++ b/drivers/infiniband/core/umem_dmabuf.h
@@ -0,0 +1,14 @@
+/* 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
+
+int ib_umem_dmabuf_map_pages(struct ib_umem *umem, u64 user_virt, u64 bcnt,
+ u64 access_mask, unsigned long current_seq);
+void ib_umem_dmabuf_unmap_pages(struct ib_umem *umem);
+void ib_umem_dmabuf_release(struct ib_umem *umem);
+
+#endif /* UMEM_DMABUF_H */
diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
index cc6b4be..7e11619 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -1,5 +1,6 @@
/*
* Copyright (c) 2014 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
@@ -47,6 +48,7 @@
#include <rdma/ib_umem_odp.h>
#include "uverbs.h"
+#include "umem_dmabuf.h"
static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
const struct mmu_interval_notifier_ops *ops)
@@ -263,6 +265,9 @@ struct ib_umem_odp *ib_umem_odp_get(struct ib_device *device,
void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
{
+ if (umem_odp->umem.is_dmabuf)
+ return ib_umem_dmabuf_release(&umem_odp->umem);
+
/*
* Ensure that no more pages are mapped in the umem.
*
@@ -392,6 +397,10 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,
unsigned int flags = 0, page_shift;
phys_addr_t p = 0;
+ if (umem_odp->umem.is_dmabuf)
+ return ib_umem_dmabuf_map_pages(&umem_odp->umem, user_virt,
+ bcnt, access_mask, current_seq);
+
if (access_mask == 0)
return -EINVAL;
@@ -517,6 +526,9 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
u64 addr;
struct ib_device *dev = umem_odp->umem.ibdev;
+ if (umem_odp->umem.is_dmabuf)
+ return ib_umem_dmabuf_unmap_pages(&umem_odp->umem);
+
lockdep_assert_held(&umem_odp->umem_mutex);
virt = max_t(u64, virt, ib_umem_start(umem_odp));
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 71f573a..b8ea693 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
@@ -13,6 +14,7 @@
struct ib_ucontext;
struct ib_umem_odp;
+struct ib_umem_dmabuf;
struct ib_umem {
struct ib_device *ibdev;
@@ -21,6 +23,7 @@ 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;
@@ -51,6 +54,13 @@ 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 mmu_interval_notifier_ops *ops);
+unsigned long ib_umem_dmabuf_notifier_read_begin(struct ib_umem_odp *umem_odp);
+int ib_umem_dmabuf_notifier_read_retry(struct ib_umem_odp *umem_odp,
+ unsigned long current_seq);
#else /* CONFIG_INFINIBAND_USER_MEM */
@@ -73,7 +83,14 @@ static inline int ib_umem_find_best_pgsz(struct ib_umem *umem,
unsigned long virt) {
return -EINVAL;
}
+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 mmu_interval_notifier_ops *ops)
+{
+ return ERR_PTR(-EINVAL);
+}
#endif /* CONFIG_INFINIBAND_USER_MEM */
-
#endif /* IB_UMEM_H */
--
1.8.3.1
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