[PATCH for-next v4 0/6] Replace AV by AH in UD sends

[PATCH for-next v4 0/6] Replace AV by AH in UD sends

[Bob Pearson]

Currently the rdma_rxe driver and its user space provider exchange
addressing information for UD sends by having the provider compute an
address vector (AV) and send it with each WQE. This is not the way
that the RDMA verbs API was intended to operate.

This series of patches modifies the way UD send WQEs work by exchanging
an index identifying the AH replacing the 88 byte AV by a 4 byte AH
index. In order to not break compatibility with the existing API the
rdma_rxe driver will recognise when an older version of the provider
is not sending an index (i.e. it is 0) and will use the AV instead.

This series of patches is almost identical to an earlier version
but rebased to 5.15.0-rc1+. It applies cleanly to

    450f4f6aa1a369cc3ffadc1c7e27dfab3e90199f (for-next)

v4:
  Rebase to 5.15.0-rc1+

v3:
  Split up commits into smaller steps.

v2:
  Rearranged AV in rxe_send_wqe to be in the ud struct but padded to the
  same offset as the original preserving ABI compatibility.

Bob Pearson (6):
  RDMA/rxe: Move AV from rxe_send_wqe to rxe_send_wr
  RDMA/rxe: Change AH objects to indexed
  RDMA/rxe: Create AH index and return to user space
  RDMA/rxe: Replace ah->pd by ah->ibah.pd
  RDMA/rxe: Lookup kernel AH from ah index in UD WQEs
  RDMA/rxe: Convert kernel UD post send to use ah_num

 drivers/infiniband/sw/rxe/rxe_av.c    | 20 +++++++++++++-
 drivers/infiniband/sw/rxe/rxe_param.h |  4 ++-
 drivers/infiniband/sw/rxe/rxe_pool.c  |  4 ++-
 drivers/infiniband/sw/rxe/rxe_req.c   |  8 +++---
 drivers/infiniband/sw/rxe/rxe_verbs.c | 39 ++++++++++++++++++++++-----
 drivers/infiniband/sw/rxe/rxe_verbs.h |  8 +++++-
 include/uapi/rdma/rdma_user_rxe.h     | 10 ++++++-
 7 files changed, 79 insertions(+), 14 deletions(-)

-- 
2.30.2

[PATCH for-next v4 1/6] RDMA/rxe: Move AV from rxe_send_wqe to rxe_send_wr

[Bob Pearson]

Move the struct rxe_av av from struct rxe_send_wqe to struct rxe_send_wr
placing it in wr.ud at the same offset as it was previously. This has the
effect of increasing the size of struct rxe_send_wr while keeping the size of
struct rxe_send_wqe the same. This better reflects the use of this field
which is only used for UD sends. This change has no effect on ABI
compatibility so the modified rxe driver will operate with older versions
of rdma-core.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_av.c    | 2 +-
 drivers/infiniband/sw/rxe/rxe_verbs.c | 3 ++-
 include/uapi/rdma/rdma_user_rxe.h     | 4 +++-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_av.c b/drivers/infiniband/sw/rxe/rxe_av.c
index da2e867a1ed9..85580ea5eed0 100644
--- a/drivers/infiniband/sw/rxe/rxe_av.c
+++ b/drivers/infiniband/sw/rxe/rxe_av.c
@@ -107,5 +107,5 @@ struct rxe_av *rxe_get_av(struct rxe_pkt_info *pkt)
 	if (qp_type(pkt->qp) == IB_QPT_RC || qp_type(pkt->qp) == IB_QPT_UC)
 		return &pkt->qp->pri_av;
 
-	return (pkt->wqe) ? &pkt->wqe->av : NULL;
+	return (pkt->wqe) ? &pkt->wqe->wr.wr.ud.av : NULL;
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 9d0bb9aa7514..c09e1c25ce66 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -584,7 +584,8 @@ static void init_send_wqe(struct rxe_qp *qp, const struct ib_send_wr *ibwr,
 	if (qp_type(qp) == IB_QPT_UD ||
 	    qp_type(qp) == IB_QPT_SMI ||
 	    qp_type(qp) == IB_QPT_GSI)
-		memcpy(&wqe->av, &to_rah(ud_wr(ibwr)->ah)->av, sizeof(wqe->av));
+		memcpy(&wqe->wr.wr.ud.av, &to_rah(ud_wr(ibwr)->ah)->av,
+		       sizeof(struct rxe_av));
 
 	if (unlikely(ibwr->send_flags & IB_SEND_INLINE))
 		copy_inline_data_to_wqe(wqe, ibwr);
diff --git a/include/uapi/rdma/rdma_user_rxe.h b/include/uapi/rdma/rdma_user_rxe.h
index e283c2220aba..2f1ebbe96434 100644
--- a/include/uapi/rdma/rdma_user_rxe.h
+++ b/include/uapi/rdma/rdma_user_rxe.h
@@ -98,6 +98,9 @@ struct rxe_send_wr {
 			__u32	remote_qpn;
 			__u32	remote_qkey;
 			__u16	pkey_index;
+			__u16	reserved;
+			__u32	pad[5];
+			struct rxe_av av;
 		} ud;
 		struct {
 			__aligned_u64	addr;
@@ -148,7 +151,6 @@ struct rxe_dma_info {
 
 struct rxe_send_wqe {
 	struct rxe_send_wr	wr;
-	struct rxe_av		av;
 	__u32			status;
 	__u32			state;
 	__aligned_u64		iova;
-- 
2.30.2

[PATCH for-next v4 2/6] RDMA/rxe: Change AH objects to indexed

[Bob Pearson]

Make changes to rxe_param.h and rxe_pool.c to allow indexing of AH
objects. Valid indices are non-zero so older providers can be detected.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_param.h | 4 +++-
 drivers/infiniband/sw/rxe/rxe_pool.c  | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_param.h b/drivers/infiniband/sw/rxe/rxe_param.h
index b5a70cbe94aa..d92d7edd712b 100644
--- a/drivers/infiniband/sw/rxe/rxe_param.h
+++ b/drivers/infiniband/sw/rxe/rxe_param.h
@@ -67,7 +67,9 @@ enum rxe_device_param {
 	RXE_MAX_MCAST_GRP		= 8192,
 	RXE_MAX_MCAST_QP_ATTACH		= 56,
 	RXE_MAX_TOT_MCAST_QP_ATTACH	= 0x70000,
-	RXE_MAX_AH			= 100,
+	RXE_MAX_AH			= 16383,
+	RXE_MIN_AH_INDEX		= 1,
+	RXE_MAX_AH_INDEX		= 16383,
 	RXE_MAX_SRQ_WR			= 0x4000,
 	RXE_MIN_SRQ_WR			= 1,
 	RXE_MAX_SRQ_SGE			= 27,
diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index ffa8420b4765..7b4cb46edfd9 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -26,7 +26,9 @@ struct rxe_type_info rxe_type_info[RXE_NUM_TYPES] = {
 		.name		= "rxe-ah",
 		.size		= sizeof(struct rxe_ah),
 		.elem_offset	= offsetof(struct rxe_ah, pelem),
-		.flags		= RXE_POOL_NO_ALLOC,
+		.flags		= RXE_POOL_INDEX | RXE_POOL_NO_ALLOC,
+		.min_index	= RXE_MIN_AH_INDEX,
+		.max_index	= RXE_MAX_AH_INDEX,
 	},
 	[RXE_TYPE_SRQ] = {
 		.name		= "rxe-srq",
-- 
2.30.2

[PATCH for-next v4 3/6] RDMA/rxe: Create AH index and return to user space

[Bob Pearson]

Make changes to rdma_user_rxe.h to allow indexing AH objects, passing
the index in UD send WRs to the driver and returning the index to the rxe
provider.

Modify rxe_create_ah() to add an index to AH when created and if
called from a new user provider return it to user space. If called
from an old provider mark the AH as not having a useful index.
Modify rxe_destroy_ah to drop the index before deleting the object.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_verbs.c | 31 ++++++++++++++++++++++++++-
 drivers/infiniband/sw/rxe/rxe_verbs.h |  2 ++
 include/uapi/rdma/rdma_user_rxe.h     |  8 ++++++-
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index c09e1c25ce66..8854ace63acd 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -158,9 +158,19 @@ static int rxe_create_ah(struct ib_ah *ibah,
 			 struct ib_udata *udata)
 
 {
-	int err;
 	struct rxe_dev *rxe = to_rdev(ibah->device);
 	struct rxe_ah *ah = to_rah(ibah);
+	struct rxe_create_ah_resp __user *uresp = NULL;
+	int err;
+
+	if (udata) {
+		/* test if new user provider */
+		if (udata->outlen >= sizeof(*uresp))
+			uresp = udata->outbuf;
+		ah->is_user = true;
+	} else {
+		ah->is_user = false;
+	}
 
 	err = rxe_av_chk_attr(rxe, init_attr->ah_attr);
 	if (err)
@@ -170,6 +180,24 @@ static int rxe_create_ah(struct ib_ah *ibah,
 	if (err)
 		return err;
 
+	/* create index > 0 */
+	rxe_add_index(ah);
+	ah->ah_num = ah->pelem.index;
+
+	if (uresp) {
+		/* only if new user provider */
+		err = copy_to_user(&uresp->ah_num, &ah->ah_num,
+					 sizeof(uresp->ah_num));
+		if (err) {
+			rxe_drop_index(ah);
+			rxe_drop_ref(ah);
+			return -EFAULT;
+		}
+	} else if (ah->is_user) {
+		/* only if old user provider */
+		ah->ah_num = 0;
+	}
+
 	rxe_init_av(init_attr->ah_attr, &ah->av);
 	return 0;
 }
@@ -202,6 +230,7 @@ static int rxe_destroy_ah(struct ib_ah *ibah, u32 flags)
 {
 	struct rxe_ah *ah = to_rah(ibah);
 
+	rxe_drop_index(ah);
 	rxe_drop_ref(ah);
 	return 0;
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h b/drivers/infiniband/sw/rxe/rxe_verbs.h
index c807639435eb..9cd203f1fa22 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.h
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.h
@@ -48,6 +48,8 @@ struct rxe_ah {
 	struct rxe_pool_entry	pelem;
 	struct rxe_pd		*pd;
 	struct rxe_av		av;
+	bool			is_user;
+	int			ah_num;
 };
 
 struct rxe_cqe {
diff --git a/include/uapi/rdma/rdma_user_rxe.h b/include/uapi/rdma/rdma_user_rxe.h
index 2f1ebbe96434..dc9f7a5e203a 100644
--- a/include/uapi/rdma/rdma_user_rxe.h
+++ b/include/uapi/rdma/rdma_user_rxe.h
@@ -99,7 +99,8 @@ struct rxe_send_wr {
 			__u32	remote_qkey;
 			__u16	pkey_index;
 			__u16	reserved;
-			__u32	pad[5];
+			__u32	ah_num;
+			__u32	pad[4];
 			struct rxe_av av;
 		} ud;
 		struct {
@@ -170,6 +171,11 @@ struct rxe_recv_wqe {
 	struct rxe_dma_info	dma;
 };
 
+struct rxe_create_ah_resp {
+	__u32 ah_num;
+	__u32 reserved;
+};
+
 struct rxe_create_cq_resp {
 	struct mminfo mi;
 };
-- 
2.30.2

[PATCH for-next v4 4/6] RDMA/rxe: Replace ah->pd by ah->ibah.pd

[Bob Pearson]

The pd field in struct rxe_ah is redundant with the pd field in the
rdma-core's ib_ah. Eliminate the pd field in rxe_ah and add an inline
to extract the pd from the ibah field.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_verbs.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h b/drivers/infiniband/sw/rxe/rxe_verbs.h
index 9cd203f1fa22..881a5159a7d0 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.h
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.h
@@ -46,7 +46,6 @@ struct rxe_pd {
 struct rxe_ah {
 	struct ib_ah		ibah;
 	struct rxe_pool_entry	pelem;
-	struct rxe_pd		*pd;
 	struct rxe_av		av;
 	bool			is_user;
 	int			ah_num;
@@ -471,6 +470,11 @@ static inline struct rxe_mw *to_rmw(struct ib_mw *mw)
 	return mw ? container_of(mw, struct rxe_mw, ibmw) : NULL;
 }
 
+static inline struct rxe_pd *rxe_ah_pd(struct rxe_ah *ah)
+{
+	return to_rpd(ah->ibah.pd);
+}
+
 static inline struct rxe_pd *mr_pd(struct rxe_mr *mr)
 {
 	return to_rpd(mr->ibmr.pd);
-- 
2.30.2

[PATCH for-next v4 5/6] RDMA/rxe: Lookup kernel AH from ah index in UD WQEs

[Bob Pearson]

Add code to rxe_get_av in rxe_av.c to use the AH index in UD send WQEs
to lookup the kernel AH. For old user providers continue to use the AV
passed in WQEs. Move setting pkt->rxe to before the call to rxe_get_av()
to get access to the AH pool.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_av.c  | 20 +++++++++++++++++++-
 drivers/infiniband/sw/rxe/rxe_req.c |  8 +++++---
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_av.c b/drivers/infiniband/sw/rxe/rxe_av.c
index 85580ea5eed0..38c7b6fb39d7 100644
--- a/drivers/infiniband/sw/rxe/rxe_av.c
+++ b/drivers/infiniband/sw/rxe/rxe_av.c
@@ -101,11 +101,29 @@ void rxe_av_fill_ip_info(struct rxe_av *av, struct rdma_ah_attr *attr)
 
 struct rxe_av *rxe_get_av(struct rxe_pkt_info *pkt)
 {
+	struct rxe_ah *ah;
+	u32 ah_num;
+
 	if (!pkt || !pkt->qp)
 		return NULL;
 
 	if (qp_type(pkt->qp) == IB_QPT_RC || qp_type(pkt->qp) == IB_QPT_UC)
 		return &pkt->qp->pri_av;
 
-	return (pkt->wqe) ? &pkt->wqe->wr.wr.ud.av : NULL;
+	if (!pkt->wqe)
+		return NULL;
+
+	ah_num = pkt->wqe->wr.wr.ud.ah_num;
+	if (ah_num) {
+		/* only new user provider or kernel client */
+		ah = rxe_pool_get_index(&pkt->rxe->ah_pool, ah_num);
+		if (!ah || ah->ah_num != ah_num || rxe_ah_pd(ah) != pkt->qp->pd) {
+			pr_warn("Unable to find AH matching ah_num\n");
+			return NULL;
+		}
+		return &ah->av;
+	}
+
+	/* only old user provider for UD sends*/
+	return &pkt->wqe->wr.wr.ud.av;
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
index 2981b3ef3cc0..06f642f942f7 100644
--- a/drivers/infiniband/sw/rxe/rxe_req.c
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -379,9 +379,8 @@ static struct sk_buff *init_req_packet(struct rxe_qp *qp,
 	/* length from start of bth to end of icrc */
 	paylen = rxe_opcode[opcode].length + payload + pad + RXE_ICRC_SIZE;
 
-	/* pkt->hdr, rxe, port_num and mask are initialized in ifc
-	 * layer
-	 */
+	/* pkt->hdr, port_num and mask are initialized in ifc layer */
+	pkt->rxe	= rxe;
 	pkt->opcode	= opcode;
 	pkt->qp		= qp;
 	pkt->psn	= qp->req.psn;
@@ -391,6 +390,9 @@ static struct sk_buff *init_req_packet(struct rxe_qp *qp,
 
 	/* init skb */
 	av = rxe_get_av(pkt);
+	if (!av)
+		return NULL;
+
 	skb = rxe_init_packet(rxe, av, paylen, pkt);
 	if (unlikely(!skb))
 		return NULL;
-- 
2.30.2

[PATCH for-next v4 6/6] RDMA/rxe: Convert kernel UD post send to use ah_num

[Bob Pearson]

Modify ib_post_send for kernel UD sends to put the AH index into the
WQE instead of the address vector.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe_verbs.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 8854ace63acd..b808777e2221 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -537,8 +537,11 @@ static void init_send_wr(struct rxe_qp *qp, struct rxe_send_wr *wr,
 	if (qp_type(qp) == IB_QPT_UD ||
 	    qp_type(qp) == IB_QPT_SMI ||
 	    qp_type(qp) == IB_QPT_GSI) {
+		struct ib_ah *ibah = ud_wr(ibwr)->ah;
+
 		wr->wr.ud.remote_qpn = ud_wr(ibwr)->remote_qpn;
 		wr->wr.ud.remote_qkey = ud_wr(ibwr)->remote_qkey;
+		wr->wr.ud.ah_num = to_rah(ibah)->ah_num;
 		if (qp_type(qp) == IB_QPT_GSI)
 			wr->wr.ud.pkey_index = ud_wr(ibwr)->pkey_index;
 		if (wr->opcode == IB_WR_SEND_WITH_IMM)
@@ -610,12 +613,6 @@ static void init_send_wqe(struct rxe_qp *qp, const struct ib_send_wr *ibwr,
 		return;
 	}
 
-	if (qp_type(qp) == IB_QPT_UD ||
-	    qp_type(qp) == IB_QPT_SMI ||
-	    qp_type(qp) == IB_QPT_GSI)
-		memcpy(&wqe->wr.wr.ud.av, &to_rah(ud_wr(ibwr)->ah)->av,
-		       sizeof(struct rxe_av));
-
 	if (unlikely(ibwr->send_flags & IB_SEND_INLINE))
 		copy_inline_data_to_wqe(wqe, ibwr);
 	else
-- 
2.30.2

Re: [PATCH for-next v4 0/6] Replace AV by AH in UD sends

[Jason Gunthorpe]

On Wed, Sep 29, 2021 at 11:25:58PM -0500, Bob Pearson wrote:
> Currently the rdma_rxe driver and its user space provider exchange
> addressing information for UD sends by having the provider compute an
> address vector (AV) and send it with each WQE. This is not the way
> that the RDMA verbs API was intended to operate.
> 
> This series of patches modifies the way UD send WQEs work by exchanging
> an index identifying the AH replacing the 88 byte AV by a 4 byte AH
> index. In order to not break compatibility with the existing API the
> rdma_rxe driver will recognise when an older version of the provider
> is not sending an index (i.e. it is 0) and will use the AV instead.
> 
> This series of patches is almost identical to an earlier version
> but rebased to 5.15.0-rc1+. It applies cleanly to
> 
>     450f4f6aa1a369cc3ffadc1c7e27dfab3e90199f (for-next)

It looks OK, but please rebase/resend it across Rao's patch to here:

commit 0994a1bcd5f7c0bf7ca3b4938d4f0f6928ac7886
Author: Rao Shoaib <Rao.Shoaib@oracle.com>
Date:   Tue Sep 14 18:12:20 2021 -0700

    RDMA/rxe: Bump up default maximum values used via uverbs
    
    In our internal testing we have found that default maximum values are too
    small.  Ideally there should be no limits, but since maximum values are
    reported via ibv_query_device, we have to return some value. So, the
    default maximums have been changed to large values.
    
    Link: https://lore.kernel.org/r/20210915011220.307585-1-Rao.Shoaib@oracle.com
    Signed-off-by: Rao Shoaib <Rao.Shoaib@oracle.com>
    Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Jason