[PATCH for-next v4 7/8] RDMA/rxe: Add support for Send/Recv/Write/Read with ODP
From: Daisuke Matsuda
Date: Wed Apr 19 2023 - 01:53:18 EST
rxe_mr_copy() is used widely to copy data to/from a user MR. requester uses
it to load payloads of requesting packets; responder uses it to process
Send, Write, and Read operaetions; completer uses it to copy data from
response packets of Read and Atomic operations to a user MR.
Allow these operations to be used with ODP by adding a subordinate function
rxe_odp_mr_copy(). It is comprised of the following steps:
1. Check the driver page table(umem_odp->dma_list) to see if pages being
accessed are present with appropriate permission.
2. If necessary, trigger page fault to map the pages.
3. Update the MR xarray using PFNs in umem_odp->pfn_list.
4. Execute data copy to/from the pages.
umem_mutex is used to ensure that dma_list (an array of addresses of an MR)
is not changed while it is being checked and that mapped pages are not
invalidated before data copy completes.
Signed-off-by: Daisuke Matsuda <matsuda-daisuke@xxxxxxxxxxx>
---
drivers/infiniband/sw/rxe/rxe.c | 10 +++
drivers/infiniband/sw/rxe/rxe_loc.h | 8 ++
drivers/infiniband/sw/rxe/rxe_mr.c | 2 +-
drivers/infiniband/sw/rxe/rxe_odp.c | 109 ++++++++++++++++++++++++++++
4 files changed, 128 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/infiniband/sw/rxe/rxe.c
index f2284d27229b..207a022156f0 100644
--- a/drivers/infiniband/sw/rxe/rxe.c
+++ b/drivers/infiniband/sw/rxe/rxe.c
@@ -79,6 +79,16 @@ static void rxe_init_device_param(struct rxe_dev *rxe)
/* IB_ODP_SUPPORT_IMPLICIT is not supported right now. */
rxe->attr.odp_caps.general_caps |= IB_ODP_SUPPORT;
+
+ rxe->attr.odp_caps.per_transport_caps.ud_odp_caps |= IB_ODP_SUPPORT_SEND;
+ rxe->attr.odp_caps.per_transport_caps.ud_odp_caps |= IB_ODP_SUPPORT_RECV;
+ rxe->attr.odp_caps.per_transport_caps.ud_odp_caps |= IB_ODP_SUPPORT_SRQ_RECV;
+
+ rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_SEND;
+ rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_RECV;
+ rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_WRITE;
+ rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_READ;
+ rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_SRQ_RECV;
}
}
diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index 0f91e23c151e..35c2ccb2fdd9 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -206,6 +206,8 @@ static inline unsigned int wr_opcode_mask(int opcode, struct rxe_qp *qp)
#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
int rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length,
u64 iova, int access_flags, struct rxe_mr *mr);
+int rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
+ enum rxe_mr_copy_dir dir);
#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
static inline int
rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
@@ -213,6 +215,12 @@ rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
{
return -EOPNOTSUPP;
}
+static inline int
+rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
+ int length, enum rxe_mr_copy_dir dir)
+{
+ return -EOPNOTSUPP;
+}
#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index cd368cd096c8..0e3cda59d702 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -319,7 +319,7 @@ int rxe_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
}
if (mr->odp_enabled)
- return -EOPNOTSUPP;
+ return rxe_odp_mr_copy(mr, iova, addr, length, dir);
else
return rxe_mr_copy_xarray(mr, iova, addr, length, dir);
}
diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
index e5497d09c399..cbe5d0c3fcc4 100644
--- a/drivers/infiniband/sw/rxe/rxe_odp.c
+++ b/drivers/infiniband/sw/rxe/rxe_odp.c
@@ -174,3 +174,112 @@ int rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length,
return err;
}
+
+static inline bool rxe_is_pagefault_neccesary(struct ib_umem_odp *umem_odp,
+ u64 iova, int length, u32 perm)
+{
+ int idx;
+ u64 addr;
+ bool need_fault = false;
+
+ addr = iova & (~(BIT(umem_odp->page_shift) - 1));
+
+ /* Skim through all pages that are to be accessed. */
+ while (addr < iova + length) {
+ idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
+
+ if (!(umem_odp->dma_list[idx] & perm)) {
+ need_fault = true;
+ break;
+ }
+
+ addr += BIT(umem_odp->page_shift);
+ }
+ return need_fault;
+}
+
+/* umem mutex must be locked before entering this function. */
+static int rxe_odp_map_range(struct rxe_mr *mr, u64 iova, int length, u32 flags)
+{
+ struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+ const int max_tries = 3;
+ int cnt = 0;
+
+ int err;
+ u64 perm;
+ bool need_fault;
+
+ if (unlikely(length < 1)) {
+ mutex_unlock(&umem_odp->umem_mutex);
+ return -EINVAL;
+ }
+
+ perm = ODP_READ_ALLOWED_BIT;
+ if (!(flags & RXE_PAGEFAULT_RDONLY))
+ perm |= ODP_WRITE_ALLOWED_BIT;
+
+ /*
+ * A successful return from rxe_odp_do_pagefault() does not guarantee
+ * that all pages in the range became present. Recheck the DMA address
+ * array, allowing max 3 tries for pagefault.
+ */
+ while ((need_fault = rxe_is_pagefault_neccesary(umem_odp,
+ iova, length, perm))) {
+ if (cnt >= max_tries)
+ break;
+
+ mutex_unlock(&umem_odp->umem_mutex);
+
+ /* umem_mutex is locked on success. */
+ err = rxe_odp_do_pagefault(mr, iova, length, flags);
+ if (err < 0)
+ return err;
+
+ cnt++;
+ }
+
+ if (need_fault)
+ return -EFAULT;
+
+ return 0;
+}
+
+int rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
+ enum rxe_mr_copy_dir dir)
+{
+ struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+ u32 flags = 0;
+ int err;
+
+ if (unlikely(!mr->odp_enabled))
+ return -EOPNOTSUPP;
+
+ switch (dir) {
+ case RXE_TO_MR_OBJ:
+ break;
+
+ case RXE_FROM_MR_OBJ:
+ flags = RXE_PAGEFAULT_RDONLY;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ /* If pagefault is not required, umem mutex will be held until data
+ * copy to the MR completes. Otherwise, it is released and locked
+ * again in rxe_odp_map_range() to let invalidation handler do its
+ * work meanwhile.
+ */
+ mutex_lock(&umem_odp->umem_mutex);
+
+ err = rxe_odp_map_range(mr, iova, length, flags);
+ if (err)
+ return err;
+
+ err = rxe_mr_copy_xarray(mr, iova, addr, length, dir);
+
+ mutex_unlock(&umem_odp->umem_mutex);
+
+ return err;
+}
--
2.39.1