[PATCH net-next 04/10] net/smc: use separate memory regions for RMBs

Ursula Braun
2017-07-28T11:56:16Z

SMC currently uses the unsafe_global_rkey of the protection domain,
which exposes all memory for remote reads and writes once a connection
is established. This patch introduces separate memory regions with
separate rkeys for every RMB. Now the unsafe_global_rkey of the
protection domain is no longer needed.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
---
net/smc/smc_clc.c | 4 ++--
net/smc/smc_core.c | 18 ++++++++++++++++++
net/smc/smc_core.h | 6 +++++-
net/smc/smc_ib.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
net/smc/smc_ib.h | 5 +++--
5 files changed, 71 insertions(+), 7 deletions(-)

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 15cb76019009..3934913ab835 100644
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -204,7 +204,7 @@ int smc_clc_send_confirm(struct smc_sock *smc)
memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
hton24(cclc.qpn, link->roce_qp->qp_num);
cclc.rmb_rkey =
- htonl(link->roce_pd->unsafe_global_rkey);
+ htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
cclc.conn_idx = 1; /* for now: 1 RMB = 1 RMBE */
cclc.rmbe_alert_token = htonl(conn->alert_token_local);
cclc.qp_mtu = min(link->path_mtu, link->peer_mtu);
@@ -256,7 +256,7 @@ int smc_clc_send_accept(struct smc_sock *new_smc, int srv_first_contact)
memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
hton24(aclc.qpn, link->roce_qp->qp_num);
aclc.rmb_rkey =
- htonl(link->roce_pd->unsafe_global_rkey);
+ htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
aclc.conn_idx = 1; /* as long as 1 RMB = 1 RMBE */
aclc.rmbe_alert_token = htonl(conn->alert_token_local);
aclc.qp_mtu = link->path_mtu;
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index bfdbda795f67..f1dd4e1cd3e1 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -218,6 +218,7 @@ static void smc_sndbuf_unuse(struct smc_connection *conn)
static void smc_rmb_unuse(struct smc_connection *conn)
{
if (conn->rmb_desc) {
+ conn->rmb_desc->reused = true;
conn->rmb_desc->used = 0;
conn->rmbe_size = 0;
}
@@ -274,6 +275,8 @@ static void smc_lgr_free_rmbs(struct smc_link_group *lgr)
list_for_each_entry_safe(rmb_desc, bf_desc, &lgr->rmbs[i],
list) {
list_del(&rmb_desc->list);
+ smc_ib_put_memory_region(
+ rmb_desc->mr_rx[SMC_SINGLE_LINK]);
smc_ib_buf_unmap_sg(lnk->smcibdev, rmb_desc,
DMA_FROM_DEVICE);
kfree(rmb_desc->cpu_addr);
@@ -627,6 +630,21 @@ int smc_rmb_create(struct smc_sock *smc)
rmb_desc = NULL;
continue; /* if mapping failed, try smaller one */
}
+ rc = smc_ib_get_memory_region(lgr->lnk[SMC_SINGLE_LINK].roce_pd,
+ IB_ACCESS_REMOTE_WRITE |
+ IB_ACCESS_LOCAL_WRITE,
+ rmb_desc);
+ if (rc) {
+ smc_ib_buf_unmap_sg(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
+ rmb_desc, DMA_FROM_DEVICE);
+ sg_free_table(&rmb_desc->sgt[SMC_SINGLE_LINK]);
+ free_pages((unsigned long)rmb_desc->cpu_addr,
+ rmb_desc->order);
+ kfree(rmb_desc);
+ rmb_desc = NULL;
+ continue;
+ }
+
rmb_desc->used = 1;
write_lock_bh(&lgr->rmbs_lock);
list_add(&rmb_desc->list, &lgr->rmbs[bufsize_short]);
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 0ee450d69907..17b5fea09901 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -94,8 +94,13 @@ struct smc_buf_desc {
/* mapped address of buffer */
void *cpu_addr; /* virtual address of buffer */
struct sg_table sgt[SMC_LINKS_PER_LGR_MAX];/* virtual buffer */
+ struct ib_mr *mr_rx[SMC_LINKS_PER_LGR_MAX];
+ /* for rmb only: memory region
+ * incl. rkey provided to peer
+ */
u32 order; /* allocation order */
u32 used; /* currently used / unused */
+ bool reused; /* new created / reused */
};

struct smc_rtoken { /* address/key of remote RMB */
@@ -175,5 +180,4 @@ int smc_sndbuf_create(struct smc_sock *smc);
int smc_rmb_create(struct smc_sock *smc);
int smc_rmb_rtoken_handling(struct smc_connection *conn,
struct smc_clc_msg_accept_confirm *clc);
-
#endif
diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index fcfeb89b05d9..08233492ec45 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -192,8 +192,7 @@ int smc_ib_create_protection_domain(struct smc_link *lnk)
{
int rc;

- lnk->roce_pd = ib_alloc_pd(lnk->smcibdev->ibdev,
- IB_PD_UNSAFE_GLOBAL_RKEY);
+ lnk->roce_pd = ib_alloc_pd(lnk->smcibdev->ibdev, 0);
rc = PTR_ERR_OR_ZERO(lnk->roce_pd);
if (IS_ERR(lnk->roce_pd))
lnk->roce_pd = NULL;
@@ -254,6 +253,48 @@ int smc_ib_create_queue_pair(struct smc_link *lnk)
return rc;
}

+void smc_ib_put_memory_region(struct ib_mr *mr)
+{
+ ib_dereg_mr(mr);
+}
+
+static int smc_ib_map_mr_sg(struct smc_buf_desc *buf_slot)
+{
+ unsigned int offset = 0;
+ int sg_num;
+
+ /* map the largest prefix of a dma mapped SG list */
+ sg_num = ib_map_mr_sg(buf_slot->mr_rx[SMC_SINGLE_LINK],
+ buf_slot->sgt[SMC_SINGLE_LINK].sgl,
+ buf_slot->sgt[SMC_SINGLE_LINK].orig_nents,
+ &offset, PAGE_SIZE);
+
+ return sg_num;
+}
+
+/* Allocate a memory region and map the dma mapped SG list of buf_slot */
+int smc_ib_get_memory_region(struct ib_pd *pd, int access_flags,
+ struct smc_buf_desc *buf_slot)
+{
+ if (buf_slot->mr_rx[SMC_SINGLE_LINK])
+ return 0; /* already done */
+
+ buf_slot->mr_rx[SMC_SINGLE_LINK] =
+ ib_alloc_mr(pd, IB_MR_TYPE_MEM_REG, 1 << buf_slot->order);
+ if (IS_ERR(buf_slot->mr_rx[SMC_SINGLE_LINK])) {
+ int rc;
+
+ rc = PTR_ERR(buf_slot->mr_rx[SMC_SINGLE_LINK]);
+ buf_slot->mr_rx[SMC_SINGLE_LINK] = NULL;
+ return rc;
+ }
+
+ if (smc_ib_map_mr_sg(buf_slot) != 1)
+ return -EINVAL;
+
+ return 0;
+}
+
/* map a new TX or RX buffer to DMA */
int smc_ib_buf_map(struct smc_ib_device *smcibdev, int buf_size,
struct smc_buf_desc *buf_slot,
diff --git a/net/smc/smc_ib.h b/net/smc/smc_ib.h
index b30e387854b6..b57d29f29042 100644
--- a/net/smc/smc_ib.h
+++ b/net/smc/smc_ib.h
@@ -71,6 +71,7 @@ int smc_ib_ready_link(struct smc_link *lnk);
int smc_ib_modify_qp_rts(struct smc_link *lnk);
int smc_ib_modify_qp_reset(struct smc_link *lnk);
long smc_ib_setup_per_ibdev(struct smc_ib_device *smcibdev);
-
-
+int smc_ib_get_memory_region(struct ib_pd *pd, int access_flags,
+ struct smc_buf_desc *buf_slot);
+void smc_ib_put_memory_region(struct ib_mr *mr);
#endif
--
2.11.2