[RFC PATCH v3 2/2] RDMA/rxe: Add dma-buf support

From: Shunsuke Mie
Date: Fri Oct 29 2021 - 03:03:25 EST


Implement a ib device operation ‘reg_user_mr_dmabuf’. Generate a
rxe_map from the memory space linked the passed dma-buf.

Signed-off-by: Shunsuke Mie <mie@xxxxxxxxxx>
---
drivers/infiniband/sw/rxe/rxe_loc.h | 2 +
drivers/infiniband/sw/rxe/rxe_mr.c | 113 ++++++++++++++++++++++++++
drivers/infiniband/sw/rxe/rxe_verbs.c | 34 ++++++++
3 files changed, 149 insertions(+)

diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index 1ca43b859d80..8bc19ea1a376 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -75,6 +75,8 @@ u8 rxe_get_next_key(u32 last_key);
void rxe_mr_init_dma(struct rxe_pd *pd, int access, struct rxe_mr *mr);
int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
int access, struct rxe_mr *mr);
+int rxe_mr_dmabuf_init_user(struct rxe_pd *pd, int fd, u64 start, u64 length,
+ u64 iova, int access, struct rxe_mr *mr);
int rxe_mr_init_fast(struct rxe_pd *pd, int max_pages, struct rxe_mr *mr);
int rxe_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
enum rxe_mr_copy_dir dir);
diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 53271df10e47..ba1282b99772 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -4,6 +4,8 @@
* Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
*/

+#include <linux/dma-buf.h>
+#include <linux/dma-buf-map.h>
#include "rxe.h"
#include "rxe_loc.h"

@@ -245,6 +247,114 @@ int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
return err;
}

+static int rxe_map_dmabuf_mr(struct rxe_mr *mr,
+ struct ib_umem_dmabuf *umem_dmabuf)
+{
+ struct rxe_map_set *set;
+ struct rxe_phys_buf *buf = NULL;
+ struct rxe_map **map;
+ void *vaddr, *vaddr_end;
+ int num_buf = 0;
+ int err;
+ size_t remain;
+ struct dma_buf_map dmabuf_map;
+
+ err = dma_buf_vmap(umem_dmabuf->dmabuf, &dmabuf_map);
+ if (err || dmabuf_map.is_iomem)
+ goto err_out;
+
+ set = mr->cur_map_set;
+ set->page_shift = PAGE_SHIFT;
+ set->page_mask = PAGE_SIZE - 1;
+
+ map = set->map;
+ buf = map[0]->buf;
+
+ vaddr = dmabuf_map.vaddr;
+ vaddr_end = vaddr + umem_dmabuf->dmabuf->size;
+ remain = umem_dmabuf->dmabuf->size;
+
+ for (; remain; vaddr += PAGE_SIZE) {
+ if (num_buf >= RXE_BUF_PER_MAP) {
+ map++;
+ buf = map[0]->buf;
+ num_buf = 0;
+ }
+
+ buf->addr = (uintptr_t)vaddr;
+ if (remain >= PAGE_SIZE)
+ buf->size = PAGE_SIZE;
+ else
+ buf->size = remain;
+ remain -= buf->size;
+
+ num_buf++;
+ buf++;
+ }
+
+ return 0;
+
+err_out:
+ return err;
+}
+
+static void rxe_unmap_dmabuf_mr(struct rxe_mr *mr)
+{
+ struct ib_umem_dmabuf *umem_dmabuf = to_ib_umem_dmabuf(mr->umem);
+ struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(
+ (void *)mr->cur_map_set->map[0]->buf->addr);
+
+ dma_buf_vunmap(umem_dmabuf->dmabuf, &map);
+}
+
+int rxe_mr_dmabuf_init_user(struct rxe_pd *pd, int fd, u64 start, u64 length,
+ u64 iova, int access, struct rxe_mr *mr)
+{
+ struct ib_umem_dmabuf *umem_dmabuf;
+ struct rxe_map_set *set;
+ int err;
+
+ umem_dmabuf = ib_umem_dmabuf_get(pd->ibpd.device, start, length, fd,
+ access, NULL);
+ if (IS_ERR(umem_dmabuf)) {
+ err = PTR_ERR(umem_dmabuf);
+ goto err_out;
+ }
+
+ rxe_mr_init(access, mr);
+
+ err = rxe_mr_alloc(mr, ib_umem_num_pages(&umem_dmabuf->umem), 0);
+ if (err) {
+ pr_warn("%s: Unable to allocate memory for map\n", __func__);
+ goto err_release_umem;
+ }
+
+ mr->ibmr.pd = &pd->ibpd;
+ mr->umem = &umem_dmabuf->umem;
+ mr->access = access;
+ mr->state = RXE_MR_STATE_VALID;
+ mr->type = IB_MR_TYPE_USER;
+
+ set = mr->cur_map_set;
+ set->length = length;
+ set->iova = iova;
+ set->va = start;
+ set->offset = ib_umem_offset(mr->umem);
+
+ err = rxe_map_dmabuf_mr(mr, umem_dmabuf);
+ if (err)
+ goto err_free_map_set;
+
+ return 0;
+
+err_free_map_set:
+ rxe_mr_free_map_set(mr->num_map, mr->cur_map_set);
+err_release_umem:
+ ib_umem_release(&umem_dmabuf->umem);
+err_out:
+ return err;
+}
+
int rxe_mr_init_fast(struct rxe_pd *pd, int max_pages, struct rxe_mr *mr)
{
int err;
@@ -703,6 +813,9 @@ void rxe_mr_cleanup(struct rxe_pool_entry *arg)
{
struct rxe_mr *mr = container_of(arg, typeof(*mr), pelem);

+ if (mr->umem && mr->umem->is_dmabuf)
+ rxe_unmap_dmabuf_mr(mr);
+
ib_umem_release(mr->umem);

if (mr->cur_map_set)
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 0aa0d7e52773..dc7d27b3cb90 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -940,6 +940,39 @@ static struct ib_mr *rxe_reg_user_mr(struct ib_pd *ibpd,
return ERR_PTR(err);
}

+static struct ib_mr *rxe_reg_user_mr_dmabuf(struct ib_pd *ibpd, u64 start,
+ u64 length, u64 iova, int fd,
+ int access, struct ib_udata *udata)
+{
+ int err;
+ struct rxe_dev *rxe = to_rdev(ibpd->device);
+ struct rxe_pd *pd = to_rpd(ibpd);
+ struct rxe_mr *mr;
+
+ mr = rxe_alloc(&rxe->mr_pool);
+ if (!mr) {
+ err = -ENOMEM;
+ goto err2;
+ }
+
+ rxe_add_index(mr);
+
+ rxe_add_ref(pd);
+
+ err = rxe_mr_dmabuf_init_user(pd, fd, start, length, iova, access, mr);
+ if (err)
+ goto err3;
+
+ return &mr->ibmr;
+
+err3:
+ rxe_drop_ref(pd);
+ rxe_drop_index(mr);
+ rxe_drop_ref(mr);
+err2:
+ return ERR_PTR(err);
+}
+
static struct ib_mr *rxe_alloc_mr(struct ib_pd *ibpd, enum ib_mr_type mr_type,
u32 max_num_sg)
{
@@ -1105,6 +1138,7 @@ static const struct ib_device_ops rxe_dev_ops = {
.query_qp = rxe_query_qp,
.query_srq = rxe_query_srq,
.reg_user_mr = rxe_reg_user_mr,
+ .reg_user_mr_dmabuf = rxe_reg_user_mr_dmabuf,
.req_notify_cq = rxe_req_notify_cq,
.resize_cq = rxe_resize_cq,

--
2.17.1