[PATCH V2 net-next 08/15] smc: work request (WR) base for use by LLC and CDC

Ursula Braun
2016-09-27T16:41:49Z

The base containers for RDMA transport are work requests and completion
queue entries processed through Infiniband verbs:
* allocate and initialize these areas
* map these areas to DMA
* implement the basic communication consisting of work request posting
and receival of completion queue events

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
---
net/smc/Makefile | 2 +-
net/smc/smc.h | 4 +
net/smc/smc_core.c | 11 ++
net/smc/smc_core.h | 30 +++
net/smc/smc_ib.c | 73 +++++++
net/smc/smc_ib.h | 11 ++
net/smc/smc_wr.c | 562 +++++++++++++++++++++++++++++++++++++++++++++++++++++
net/smc/smc_wr.h | 93 +++++++++
8 files changed, 785 insertions(+), 1 deletion(-)
create mode 100644 net/smc/smc_wr.c
create mode 100644 net/smc/smc_wr.h

diff --git a/net/smc/Makefile b/net/smc/Makefile
index cb8bcd9..b19120e 100644
--- a/net/smc/Makefile
+++ b/net/smc/Makefile
@@ -1,2 +1,2 @@
obj-$(CONFIG_SMC) += smc.o
-smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o smc_core.o
+smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o smc_core.o smc_wr.o
diff --git a/net/smc/smc.h b/net/smc/smc.h
index 96064a4..5967565 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -27,6 +27,10 @@ enum smc_state { /* possible states of an SMC socket */

struct smc_link_group;

+struct smc_wr_rx_hdr { /* common prefix part of LLC and CDC to demultiplex */
+ u8 type;
+} __packed;
+
struct smc_connection {
struct rb_node alert_node;
struct smc_link_group *lgr; /* link group of connection */
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index f9f981f..c05b3be 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -20,6 +20,7 @@
#include "smc_clc.h"
#include "smc_core.h"
#include "smc_ib.h"
+#include "smc_wr.h"

#define SMC_LGR_FREE_DELAY (600 * HZ)

@@ -159,12 +160,20 @@ static int smc_lgr_create(struct smc_sock *smc, __be32 peer_in_addr,
lnk->path_mtu = smcibdev->pattr[ibport - 1].active_mtu;
get_random_bytes(rndvec, sizeof(rndvec));
lnk->psn_initial = rndvec[0] + (rndvec[1] << 8) + (rndvec[2] << 16);
+ rc = smc_wr_alloc_link_mem(lnk);
+ if (rc)
+ goto free_lgr;
+ init_waitqueue_head(&lnk->wr_tx_wait);

smc->conn.lgr = lgr;
rwlock_init(&lgr->conns_lock);
spin_lock_bh(&smc_lgr_list.lock);
list_add_tail(&lgr->list, &smc_lgr_list.list);
spin_unlock_bh(&smc_lgr_list.lock);
+ return 0;
+
+free_lgr:
+ kfree(lgr);
out:
return rc;
}
@@ -200,6 +209,8 @@ void smc_conn_free(struct smc_connection *conn)
static void smc_link_clear(struct smc_link *lnk)
{
lnk->peer_qpn = 0;
+ smc_wr_free_link(lnk);
+ smc_wr_free_link_mem(lnk);
}

static void smc_lgr_free_sndbufs(struct smc_link_group *lgr)
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index ad9b16d..48325c7 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -11,6 +11,7 @@
#ifndef _SMC_CORE_H
#define _SMC_CORE_H

+#include <linux/atomic.h>
#include <rdma/ib_verbs.h>

#include "smc.h"
@@ -30,11 +31,40 @@ enum smc_lgr_role { /* possible roles of a link group */
SMC_SERV /* server */
};

+#define SMC_WR_BUF_SIZE 48 /* size of work request buffer */
+
+struct smc_wr_buf {
+ u8 raw[SMC_WR_BUF_SIZE];
+} __packed;
+
struct smc_link {
struct smc_ib_device *smcibdev; /* ib-device */
u8 ibport; /* port - values 1 | 2 */
+ struct ib_pd *roce_pd; /* IB protection domain,
+ * unique for every RoCE QP
+ */
struct ib_qp *roce_qp; /* IB queue pair */
struct ib_qp_attr qp_attr; /* IB queue pair attributes */
+
+ struct smc_wr_buf *wr_tx_bufs; /* WR send payload buffers */
+ struct ib_send_wr *wr_tx_ibs; /* WR send meta data */
+ struct ib_sge *wr_tx_sges; /* WR send gather meta data */
+ struct smc_wr_tx_pend *wr_tx_pends; /* WR send waiting for CQE */
+ /* above four vectors have wr_tx_cnt elements and use the same index */
+ dma_addr_t wr_tx_dma_addr; /* DMA address of wr_tx_bufs */
+ atomic_long_t wr_tx_id; /* seq # of last sent WR */
+ unsigned long *wr_tx_mask; /* bit mask of used indexes */
+ u32 wr_tx_cnt; /* number of WR send buffers */
+ wait_queue_head_t wr_tx_wait; /* wait for free WR send buf */
+
+ struct smc_wr_buf *wr_rx_bufs; /* WR recv payload buffers */
+ struct ib_recv_wr *wr_rx_ibs; /* WR recv meta data */
+ struct ib_sge *wr_rx_sges; /* WR recv scatter meta data */
+ /* above three vectors have wr_rx_cnt elements and use the same index */
+ dma_addr_t wr_rx_dma_addr; /* DMA address of wr_rx_bufs */
+ u64 wr_rx_id; /* seq # of last recv WR */
+ u32 wr_rx_cnt; /* number of WR recv buffers */
+
union ib_gid gid; /* gid matching used vlan id */
u32 peer_qpn; /* QP number of peer */
enum ib_mtu path_mtu; /* used mtu */
diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index 9ca1412..20b7eea 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -17,6 +17,7 @@
#include "smc_pnet.h"
#include "smc_ib.h"
#include "smc_core.h"
+#include "smc_wr.h"
#include "smc.h"

struct smc_ib_devices smc_ib_devices = { /* smc-registered ib devices */
@@ -30,6 +31,78 @@ u8 local_systemid[SMC_SYSTEMID_LEN] = SMC_LOCAL_SYSTEMID_RESET; /* unique system
* identifier
*/

+void smc_ib_dealloc_protection_domain(struct smc_link *lnk)
+{
+ ib_dealloc_pd(lnk->roce_pd);
+ lnk->roce_pd = NULL;
+}
+
+int smc_ib_create_protection_domain(struct smc_link *lnk)
+{
+ int rc;
+
+ lnk->roce_pd = ib_alloc_pd(lnk->smcibdev->ibdev);
+ rc = PTR_ERR_OR_ZERO(lnk->roce_pd);
+ if (IS_ERR(lnk->roce_pd))
+ lnk->roce_pd = NULL;
+ return rc;
+}
+
+static void smc_ib_qp_event_handler(struct ib_event *ibevent, void *priv)
+{
+ switch (ibevent->event) {
+ case IB_EVENT_DEVICE_FATAL:
+ case IB_EVENT_GID_CHANGE:
+ case IB_EVENT_PORT_ERR:
+ case IB_EVENT_QP_ACCESS_ERR:
+ /* tbd in follow-on patch:
+ * abnormal close of corresponding connections
+ */
+ break;
+ default:
+ break;
+ }
+}
+
+void smc_ib_destroy_queue_pair(struct smc_link *lnk)
+{
+ ib_destroy_qp(lnk->roce_qp);
+ lnk->roce_qp = NULL;
+}
+
+/* create a queue pair within the protection domain for a link */
+int smc_ib_create_queue_pair(struct smc_link *lnk)
+{
+ struct ib_qp_init_attr qp_attr = {
+ .event_handler = smc_ib_qp_event_handler,
+ .qp_context = lnk,
+ .send_cq = lnk->smcibdev->roce_cq_send,
+ .recv_cq = lnk->smcibdev->roce_cq_recv,
+ .srq = NULL,
+ .cap = {
+ .max_send_wr = SMC_WR_BUF_CNT,
+ /* include unsolicited rdma_writes as well,
+ * there are max. 2 RDMA_WRITE per 1 WR_SEND
+ */
+ .max_recv_wr = SMC_WR_BUF_CNT * 3,
+ .max_send_sge = SMC_IB_MAX_SEND_SGE,
+ .max_recv_sge = 1,
+ .max_inline_data = SMC_WR_TX_SIZE,
+ },
+ .sq_sig_type = IB_SIGNAL_REQ_WR,
+ .qp_type = IB_QPT_RC,
+ };
+ int rc;
+
+ lnk->roce_qp = ib_create_qp(lnk->roce_pd, &qp_attr);
+ rc = PTR_ERR_OR_ZERO(lnk->roce_qp);
+ if (IS_ERR(lnk->roce_qp))
+ lnk->roce_qp = NULL;
+ else
+ smc_wr_remember_qp_attr(lnk);
+ return rc;
+}
+
/* 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 57167af..842a27f 100644
--- a/net/smc/smc_ib.h
+++ b/net/smc/smc_ib.h
@@ -16,6 +16,8 @@
#define SMC_MAX_PORTS 2 /* Max # of ports */
#define SMC_GID_SIZE sizeof(union ib_gid)

+#define SMC_IB_MAX_SEND_SGE 2
+
struct smc_ib_devices { /* list of smc ib devices definition */
struct list_head list;
spinlock_t lock; /* protects list of smc ib devices */
@@ -27,6 +29,10 @@ struct smc_ib_device { /* ib-device infos for smc */
struct list_head list;
struct ib_device *ibdev;
struct ib_port_attr pattr[SMC_MAX_PORTS]; /* ib dev. port attrs */
+ struct ib_cq *roce_cq_send; /* send completion queue */
+ struct ib_cq *roce_cq_recv; /* recv completion queue */
+ struct tasklet_struct send_tasklet; /* called by send cq handler */
+ struct tasklet_struct recv_tasklet; /* called by recv cq handler */
char mac[SMC_MAX_PORTS][6]; /* mac address per port*/
union ib_gid gid[SMC_MAX_PORTS]; /* gid per port */
u8 initialized : 1; /* ib dev CQ, evthdl done */
@@ -34,6 +40,7 @@ struct smc_ib_device { /* ib-device infos for smc */

struct smc_sock;
struct smc_buf_desc;
+struct smc_link;

int smc_ib_register_client(void) __init;
void smc_ib_unregister_client(void);
@@ -41,5 +48,9 @@ bool smc_ib_port_active(struct smc_ib_device *, u8);
int smc_ib_remember_port_attr(struct smc_ib_device *, u8);
int smc_ib_buf_map(struct smc_ib_device *, int, struct smc_buf_desc *,
enum dma_data_direction);
+void smc_ib_dealloc_protection_domain(struct smc_link *);
+int smc_ib_create_protection_domain(struct smc_link *);
+void smc_ib_destroy_queue_pair(struct smc_link *);
+int smc_ib_create_queue_pair(struct smc_link *);

#endif
diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
new file mode 100644
index 0000000..ff77e1d
--- /dev/null
+++ b/net/smc/smc_wr.c
@@ -0,0 +1,562 @@
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ * Work Requests exploiting Infiniband API
+ *
+ * Work requests (WR) of type ib_post_send or ib_post_recv respectively
+ * are submitted to either RC SQ or RC RQ respectively
+ * (reliably connected send/receive queue)
+ * and become work queue entries (WQEs).
+ * While an SQ WR/WQE is pending, we track it until transmission completion.
+ * Through a send or receive completion queue (CQ) respectively,
+ * we get completion queue entries (CQEs) [aka work completions (WCs)].
+ * Since the CQ callback is called from IRQ context, we split work by using
+ * bottom halves implemented by tasklets.
+ *
+ * SMC uses this to exchange LLC (link layer control)
+ * and CDC (connection data control) messages.
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * Author(s): Steffen Maier <maier@linux.vnet.ibm.com>
+ */
+
+#include <linux/atomic.h>
+#include <linux/hashtable.h>
+#include <asm/div64.h>
+
+#include "smc.h"
+#include "smc_wr.h"
+
+#define SMC_WR_MAX_POLL_CQE 10 /* max. # of compl. queue elements in 1 poll */
+
+#define SMC_WR_RX_HASH_BITS 4
+static DEFINE_HASHTABLE(smc_wr_rx_hash, SMC_WR_RX_HASH_BITS);
+static DEFINE_SPINLOCK(smc_wr_rx_hash_lock);
+
+struct smc_wr_tx_pend { /* control data for a pending send request */
+ u64 wr_id; /* work request id sent */
+ smc_wr_tx_handler handler;
+ enum ib_wc_status wc_status; /* CQE status */
+ struct smc_link *link;
+ u32 idx;
+ struct smc_wr_tx_pend_priv priv;
+};
+
+/******************************** send queue *********************************/
+
+/*------------------------------- completion --------------------------------*/
+
+static inline int smc_wr_tx_find_pending_index(struct smc_link *link, u64 wr_id)
+{
+ u32 i;
+
+ for (i = 0; i < link->wr_tx_cnt; i++) {
+ if (link->wr_tx_pends[i].wr_id == wr_id)
+ return i;
+ }
+ return link->wr_tx_cnt;
+}
+
+static inline void smc_wr_tx_process_cqe(struct ib_wc *wc)
+{
+ struct smc_wr_tx_pend pnd_snd;
+ struct smc_link *link;
+ u32 pnd_snd_idx;
+ int i;
+
+ link = wc->qp->qp_context;
+ pnd_snd_idx = smc_wr_tx_find_pending_index(link, wc->wr_id);
+ if (pnd_snd_idx == link->wr_tx_cnt)
+ return;
+ link->wr_tx_pends[pnd_snd_idx].wc_status = wc->status;
+ memcpy(&pnd_snd, &link->wr_tx_pends[pnd_snd_idx], sizeof(pnd_snd));
+ /* clear the full struct smc_wr_tx_pend including .priv */
+ memset(&link->wr_tx_pends[pnd_snd_idx], 0,
+ sizeof(link->wr_tx_pends[pnd_snd_idx]));
+ memset(&link->wr_tx_bufs[pnd_snd_idx], 0,
+ sizeof(link->wr_tx_bufs[pnd_snd_idx]));
+ if (!test_and_clear_bit(pnd_snd_idx, link->wr_tx_mask))
+ return;
+ if (wc->status) {
+ for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
+ /* clear full struct smc_wr_tx_pend including .priv */
+ memset(&link->wr_tx_pends[i], 0,
+ sizeof(link->wr_tx_pends[i]));
+ memset(&link->wr_tx_bufs[i], 0,
+ sizeof(link->wr_tx_bufs[i]));
+ clear_bit(i, link->wr_tx_mask);
+ }
+ /* tbd in future patch: terminate connections of this link
+ * group abnormally
+ */
+ }
+ if (pnd_snd.handler)
+ pnd_snd.handler(&pnd_snd.priv, link, wc->status);
+ wake_up(&link->wr_tx_wait);
+}
+
+static void smc_wr_tx_tasklet_fn(unsigned long data)
+{
+ struct smc_ib_device *dev = (struct smc_ib_device *)data;
+ struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
+ int i = 0, rc;
+ int polled = 0;
+
+again:
+ polled++;
+ do {
+ rc = ib_poll_cq(dev->roce_cq_send, SMC_WR_MAX_POLL_CQE, wc);
+ if (polled == 1) {
+ ib_req_notify_cq(dev->roce_cq_send,
+ IB_CQ_NEXT_COMP |
+ IB_CQ_REPORT_MISSED_EVENTS);
+ }
+ if (!rc)
+ break;
+ for (i = 0; i < rc; i++)
+ smc_wr_tx_process_cqe(&wc[i]);
+ } while (rc > 0);
+ if (polled == 1)
+ goto again;
+}
+
+void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
+{
+ struct smc_ib_device *dev = (struct smc_ib_device *)cq_context;
+
+ tasklet_schedule(&dev->send_tasklet);
+}
+
+/*---------------------------- request submission ---------------------------*/
+
+static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
+{
+ *idx = link->wr_tx_cnt;
+ for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
+ if (!test_and_set_bit(*idx, link->wr_tx_mask))
+ return 0;
+ }
+ *idx = link->wr_tx_cnt;
+ return -EBUSY;
+}
+
+/**
+ * smc_wr_tx_get_free_slot() - returns buffer for message assembly,
+ * and sets info for pending transmit tracking
+ * @link: Pointer to smc_link used to later send the message.
+ * @handler: Send completion handler function pointer.
+ * @wr_buf: Out value returns pointer to message buffer.
+ * @wr_pend_priv: Out value returns pointer serving as handler context.
+ *
+ * Return: 0 on success, or -errno on error.
+ */
+int smc_wr_tx_get_free_slot(struct smc_link *link,
+ smc_wr_tx_handler handler,
+ struct smc_wr_buf **wr_buf,
+ struct smc_wr_tx_pend_priv **wr_pend_priv)
+{
+ struct smc_wr_tx_pend *wr_pend;
+ struct ib_send_wr *wr_ib;
+ u64 wr_id;
+ u32 idx;
+ int rc;
+
+ *wr_buf = NULL;
+ *wr_pend_priv = NULL;
+ if (in_softirq()) {
+ rc = smc_wr_tx_get_free_slot_index(link, &idx);
+ if (rc)
+ return rc;
+ } else {
+ rc = wait_event_interruptible_timeout(
+ link->wr_tx_wait,
+ (smc_wr_tx_get_free_slot_index(link, &idx) != -EBUSY),
+ SMC_WR_TX_WAIT_FREE_SLOT_TIME);
+ if (!rc) {
+ /* tbd in future patch: timeout - terminate connections
+ * of this link group abnormally
+ */
+ return -EPIPE;
+ }
+ if (rc == -ERESTARTSYS)
+ return -EINTR;
+ if (idx == link->wr_tx_cnt)
+ return -EPIPE;
+ }
+ wr_id = smc_wr_tx_get_next_wr_id(link);
+ wr_pend = &link->wr_tx_pends[idx];
+ wr_pend->wr_id = wr_id;
+ wr_pend->handler = handler;
+ wr_pend->link = link;
+ wr_pend->idx = idx;
+ wr_ib = &link->wr_tx_ibs[idx];
+ wr_ib->wr_id = wr_id;
+ *wr_buf = &link->wr_tx_bufs[idx];
+ *wr_pend_priv = &wr_pend->priv;
+ return 0;
+}
+
+int smc_wr_tx_put_slot(struct smc_link *link,
+ struct smc_wr_tx_pend_priv *wr_pend_priv)
+{
+ struct smc_wr_tx_pend *pend;
+
+ pend = container_of(wr_pend_priv, struct smc_wr_tx_pend, priv);
+ if (pend->idx < link->wr_tx_cnt) {
+ /* clear the full struct smc_wr_tx_pend including .priv */
+ memset(&link->wr_tx_pends[pend->idx], 0,
+ sizeof(link->wr_tx_pends[pend->idx]));
+ memset(&link->wr_tx_bufs[pend->idx], 0,
+ sizeof(link->wr_tx_bufs[pend->idx]));
+ test_and_clear_bit(pend->idx, link->wr_tx_mask);
+ return 1;
+ }
+
+ return 0;
+}
+
+/* Send prepared WR slot via ib_post_send.
+ * @priv: pointer to smc_wr_tx_pend_priv identifying prepared message buffer
+ */
+int smc_wr_tx_send(struct smc_link *link, struct smc_wr_tx_pend_priv *priv)
+{
+ struct ib_send_wr *failed_wr = NULL;
+ struct smc_wr_tx_pend *pend;
+ int rc;
+
+ ib_req_notify_cq(link->smcibdev->roce_cq_send,
+ IB_CQ_SOLICITED_MASK | IB_CQ_REPORT_MISSED_EVENTS);
+ pend = container_of(priv, struct smc_wr_tx_pend, priv);
+ rc = ib_post_send(link->roce_qp, &link->wr_tx_ibs[pend->idx],
+ &failed_wr);
+ if (rc)
+ smc_wr_tx_put_slot(link, priv);
+ return rc;
+}
+
+/****************************** receive queue ********************************/
+
+int smc_wr_rx_register_handler(struct smc_wr_rx_handler *handler)
+{
+ struct smc_wr_rx_handler *h_iter;
+ int rc = 0;
+
+ spin_lock(&smc_wr_rx_hash_lock);
+ hash_for_each_possible(smc_wr_rx_hash, h_iter, list, handler->type) {
+ if (h_iter->type == handler->type) {
+ rc = -EEXIST;
+ goto out_unlock;
+ }
+ }
+ hash_add(smc_wr_rx_hash, &handler->list, handler->type);
+out_unlock:
+ spin_unlock(&smc_wr_rx_hash_lock);
+ return rc;
+}
+
+/* Demultiplex a received work request based on the message type to its handler.
+ * Relies on smc_wr_rx_hash having been completely filled before any IB WRs,
+ * and not being modified any more afterwards so we don't need to lock it.
+ */
+static inline void smc_wr_rx_demultiplex(struct ib_wc *wc)
+{
+ struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
+ struct smc_wr_rx_handler *handler;
+ struct smc_wr_rx_hdr *wr_rx;
+ u64 temp_wr_id;
+ u32 index;
+
+ if (wc->byte_len < sizeof(*wr_rx))
+ return; /* short message */
+ temp_wr_id = wc->wr_id;
+ index = do_div(temp_wr_id, link->wr_rx_cnt);
+ wr_rx = (struct smc_wr_rx_hdr *)&link->wr_rx_bufs[index];
+ hash_for_each_possible(smc_wr_rx_hash, handler, list, wr_rx->type) {
+ if (handler->type == wr_rx->type)
+ handler->handler(wc, wr_rx);
+ }
+}
+
+static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num)
+{
+ struct smc_link *link;
+ int i;
+
+ for (i = 0; i < num; i++) {
+ link = wc[i].qp->qp_context;
+ if (wc[i].status == IB_WC_SUCCESS) {
+ smc_wr_rx_demultiplex(&wc[i]);
+ smc_wr_rx_post(link); /* refill WR RX */
+ } else {
+ /* handle status errors */
+ switch (wc[i].status) {
+ case IB_WC_RETRY_EXC_ERR:
+ case IB_WC_RNR_RETRY_EXC_ERR:
+ case IB_WC_WR_FLUSH_ERR:
+ /* tbd in future patch: terminate connections of this
+ * link group abnormally
+ */
+ break;
+ default:
+ smc_wr_rx_post(link); /* refill WR RX */
+ break;
+ }
+ }
+ }
+}
+
+static void smc_wr_rx_tasklet_fn(unsigned long data)
+{
+ struct smc_ib_device *dev = (struct smc_ib_device *)data;
+ struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
+ int polled = 0;
+ int rc;
+
+again:
+ polled++;
+ do {
+ memset(&wc, 0, sizeof(wc));
+ rc = ib_poll_cq(dev->roce_cq_recv, SMC_WR_MAX_POLL_CQE, wc);
+ if (polled == 1) {
+ ib_req_notify_cq(dev->roce_cq_recv,
+ IB_CQ_SOLICITED_MASK
+ | IB_CQ_REPORT_MISSED_EVENTS);
+ }
+ if (!rc)
+ break;
+ smc_wr_rx_process_cqes(&wc[0], rc);
+ } while (rc > 0);
+ if (polled == 1)
+ goto again;
+}
+
+void smc_wr_rx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
+{
+ struct smc_ib_device *dev = (struct smc_ib_device *)cq_context;
+
+ tasklet_schedule(&dev->recv_tasklet);
+}
+
+int smc_wr_rx_post_init(struct smc_link *link)
+{
+ u32 i;
+ int rc = 0;
+
+ for (i = 0; i < link->wr_rx_cnt; i++)
+ rc = smc_wr_rx_post(link);
+ return rc;
+}
+
+/***************************** init, exit, misc ******************************/
+
+void smc_wr_remember_qp_attr(struct smc_link *lnk)
+{
+ struct ib_qp_attr *attr = &lnk->qp_attr;
+ struct ib_qp_init_attr init_attr;
+
+ memset(attr, 0, sizeof(*attr));
+ memset(&init_attr, 0, sizeof(init_attr));
+ ib_query_qp(lnk->roce_qp, attr,
+ IB_QP_STATE |
+ IB_QP_CUR_STATE |
+ IB_QP_PKEY_INDEX |
+ IB_QP_PORT |
+ IB_QP_QKEY |
+ IB_QP_AV |
+ IB_QP_PATH_MTU |
+ IB_QP_TIMEOUT |
+ IB_QP_RETRY_CNT |
+ IB_QP_RNR_RETRY |
+ IB_QP_RQ_PSN |
+ IB_QP_ALT_PATH |
+ IB_QP_MIN_RNR_TIMER |
+ IB_QP_SQ_PSN |
+ IB_QP_PATH_MIG_STATE |
+ IB_QP_CAP |
+ IB_QP_DEST_QPN,
+ &init_attr);
+
+ lnk->wr_tx_cnt = min_t(size_t, SMC_WR_BUF_CNT,
+ lnk->qp_attr.cap.max_send_wr);
+ lnk->wr_rx_cnt = min_t(size_t, SMC_WR_BUF_CNT * 3,
+ lnk->qp_attr.cap.max_recv_wr);
+}
+
+static void smc_wr_init_sge(struct smc_link *lnk)
+{
+ u32 i;
+
+ for (i = 0; i < lnk->wr_tx_cnt; i++) {
+ lnk->wr_tx_sges[i].addr =
+ lnk->wr_tx_dma_addr + i * SMC_WR_BUF_SIZE;
+ lnk->wr_tx_sges[i].length = SMC_WR_TX_SIZE;
+ lnk->wr_tx_ibs[i].next = NULL;
+ lnk->wr_tx_ibs[i].sg_list = &lnk->wr_tx_sges[i];
+ lnk->wr_tx_ibs[i].num_sge = 1;
+ lnk->wr_tx_ibs[i].opcode = IB_WR_SEND;
+ lnk->wr_tx_ibs[i].send_flags =
+ IB_SEND_SIGNALED | IB_SEND_SOLICITED | IB_SEND_INLINE;
+ }
+ for (i = 0; i < lnk->wr_rx_cnt; i++) {
+ lnk->wr_rx_sges[i].addr =
+ lnk->wr_rx_dma_addr + i * SMC_WR_BUF_SIZE;
+ lnk->wr_rx_sges[i].length = SMC_WR_BUF_SIZE;
+ lnk->wr_rx_ibs[i].next = NULL;
+ lnk->wr_rx_ibs[i].sg_list = &lnk->wr_rx_sges[i];
+ lnk->wr_rx_ibs[i].num_sge = 1;
+ }
+}
+
+void smc_wr_free_link(struct smc_link *lnk)
+{
+ struct ib_device *ibdev;
+
+ memset(lnk->wr_tx_mask, 0,
+ BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
+
+ if (!lnk->smcibdev)
+ return;
+ ibdev = lnk->smcibdev->ibdev;
+
+ if (lnk->wr_rx_dma_addr) {
+ ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
+ SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
+ DMA_FROM_DEVICE);
+ lnk->wr_rx_dma_addr = 0;
+ }
+ if (lnk->wr_tx_dma_addr) {
+ ib_dma_unmap_single(ibdev, lnk->wr_tx_dma_addr,
+ SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
+ DMA_TO_DEVICE);
+ lnk->wr_tx_dma_addr = 0;
+ }
+}
+
+void smc_wr_free_link_mem(struct smc_link *lnk)
+{
+ kfree(lnk->wr_tx_pends);
+ lnk->wr_tx_pends = NULL;
+ kfree(lnk->wr_tx_mask);
+ lnk->wr_tx_mask = NULL;
+ kfree(lnk->wr_tx_sges);
+ lnk->wr_tx_sges = NULL;
+ kfree(lnk->wr_rx_sges);
+ lnk->wr_rx_sges = NULL;
+ kfree(lnk->wr_rx_ibs);
+ lnk->wr_rx_ibs = NULL;
+ kfree(lnk->wr_tx_ibs);
+ lnk->wr_tx_ibs = NULL;
+ kfree(lnk->wr_tx_bufs);
+ lnk->wr_tx_bufs = NULL;
+ kfree(lnk->wr_rx_bufs);
+ lnk->wr_rx_bufs = NULL;
+}
+
+int smc_wr_alloc_link_mem(struct smc_link *link)
+{
+ /* allocate link related memory */
+ link->wr_tx_bufs = kcalloc(SMC_WR_BUF_CNT, SMC_WR_BUF_SIZE, GFP_KERNEL);
+ if (!link->wr_tx_bufs)
+ goto no_mem;
+ link->wr_rx_bufs = kcalloc(SMC_WR_BUF_CNT * 3, SMC_WR_BUF_SIZE,
+ GFP_KERNEL);
+ if (!link->wr_rx_bufs)
+ goto no_mem_wr_tx_bufs;
+ link->wr_tx_ibs = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_ibs[0]),
+ GFP_KERNEL);
+ if (!link->wr_tx_ibs)
+ goto no_mem_wr_rx_bufs;
+ link->wr_rx_ibs = kcalloc(SMC_WR_BUF_CNT * 3,
+ sizeof(link->wr_rx_ibs[0]),
+ GFP_KERNEL);
+ if (!link->wr_rx_ibs)
+ goto no_mem_wr_tx_ibs;
+ link->wr_tx_sges = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_sges[0]),
+ GFP_KERNEL);
+ if (!link->wr_tx_sges)
+ goto no_mem_wr_rx_ibs;
+ link->wr_rx_sges = kcalloc(SMC_WR_BUF_CNT * 3,
+ sizeof(link->wr_rx_sges[0]),
+ GFP_KERNEL);
+ if (!link->wr_rx_sges)
+ goto no_mem_wr_tx_sges;
+ link->wr_tx_mask = kzalloc(
+ BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*link->wr_tx_mask),
+ GFP_KERNEL);
+ if (!link->wr_tx_mask)
+ goto no_mem_wr_rx_sges;
+ link->wr_tx_pends = kcalloc(SMC_WR_BUF_CNT,
+ sizeof(link->wr_tx_pends[0]),
+ GFP_KERNEL);
+ if (!link->wr_tx_pends)
+ goto no_mem_wr_tx_mask;
+ return 0;
+
+no_mem_wr_tx_mask:
+ kfree(link->wr_tx_mask);
+no_mem_wr_rx_sges:
+ kfree(link->wr_rx_sges);
+no_mem_wr_tx_sges:
+ kfree(link->wr_tx_sges);
+no_mem_wr_rx_ibs:
+ kfree(link->wr_rx_ibs);
+no_mem_wr_tx_ibs:
+ kfree(link->wr_tx_ibs);
+no_mem_wr_rx_bufs:
+ kfree(link->wr_rx_bufs);
+no_mem_wr_tx_bufs:
+ kfree(link->wr_tx_bufs);
+no_mem:
+ return -ENOMEM;
+}
+
+void smc_wr_remove_dev(struct smc_ib_device *smcibdev)
+{
+ tasklet_kill(&smcibdev->recv_tasklet);
+ tasklet_kill(&smcibdev->send_tasklet);
+}
+
+void smc_wr_add_dev(struct smc_ib_device *smcibdev)
+{
+ tasklet_init(&smcibdev->recv_tasklet, smc_wr_rx_tasklet_fn,
+ (unsigned long)smcibdev);
+ tasklet_init(&smcibdev->send_tasklet, smc_wr_tx_tasklet_fn,
+ (unsigned long)smcibdev);
+}
+
+int smc_wr_create_link(struct smc_link *lnk)
+{
+ struct ib_device *ibdev = lnk->smcibdev->ibdev;
+ int rc = 0;
+
+ smc_wr_tx_set_wr_id(&lnk->wr_tx_id, 0);
+ lnk->wr_rx_id = 0;
+ lnk->wr_rx_dma_addr = ib_dma_map_single(
+ ibdev, lnk->wr_rx_bufs, SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
+ DMA_FROM_DEVICE);
+ if (ib_dma_mapping_error(ibdev, lnk->wr_rx_dma_addr)) {
+ lnk->wr_rx_dma_addr = 0;
+ rc = -EIO;
+ goto out;
+ }
+ lnk->wr_tx_dma_addr = ib_dma_map_single(
+ ibdev, lnk->wr_tx_bufs, SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
+ DMA_TO_DEVICE);
+ if (ib_dma_mapping_error(ibdev, lnk->wr_tx_dma_addr)) {
+ rc = -EIO;
+ goto dma_unmap;
+ }
+ smc_wr_init_sge(lnk);
+ memset(lnk->wr_tx_mask, 0,
+ BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
+ return rc;
+
+dma_unmap:
+ ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
+ SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
+ DMA_FROM_DEVICE);
+ lnk->wr_rx_dma_addr = 0;
+out:
+ return rc;
+}
diff --git a/net/smc/smc_wr.h b/net/smc/smc_wr.h
new file mode 100644
index 0000000..95eb900
--- /dev/null
+++ b/net/smc/smc_wr.h
@@ -0,0 +1,93 @@
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ * Work Requests exploiting Infiniband API
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * Author(s): Steffen Maier <maier@linux.vnet.ibm.com>
+ */
+
+#ifndef SMC_WR_H
+#define SMC_WR_H
+
+#include <linux/atomic.h>
+#include <rdma/ib_verbs.h>
+#include <asm/div64.h>
+
+#include "smc.h"
+#include "smc_core.h"
+
+#define SMC_WR_MAX_CQE 32768 /* max. # of completion queue elements */
+#define SMC_WR_BUF_CNT 16 /* # of ctrl buffers per link */
+
+#define SMC_WR_TX_WAIT_FREE_SLOT_TIME (10 * HZ)
+#define SMC_WR_TX_WAIT_PENDING_TIME (5 * HZ)
+
+#define SMC_WR_TX_SIZE 44 /* actual size of wr_send data (<=SMC_WR_BUF_SIZE) */
+
+#define SMC_WR_TX_PEND_PRIV_SIZE 32
+
+struct smc_wr_tx_pend_priv {
+ u8 priv[SMC_WR_TX_PEND_PRIV_SIZE];
+};
+
+typedef void (*smc_wr_tx_handler)(struct smc_wr_tx_pend_priv *,
+ struct smc_link *,
+ enum ib_wc_status);
+
+struct smc_wr_rx_handler {
+ struct hlist_node list; /* hash table collision resolution */
+ void (*handler)(struct ib_wc *, void *);
+ u8 type;
+};
+
+/* Only used by RDMA write WRs.
+ * All other WRs (CDC/LLC) use smc_wr_tx_send handling WR_ID implicitly
+ */
+static inline long smc_wr_tx_get_next_wr_id(struct smc_link *link)
+{
+ return atomic_long_inc_return(&link->wr_tx_id);
+}
+
+static inline void smc_wr_tx_set_wr_id(atomic_long_t *wr_tx_id, long val)
+{
+ atomic_long_set(wr_tx_id, val);
+}
+
+/* post a new receive work request to fill a completed old work request entry */
+static inline int smc_wr_rx_post(struct smc_link *link)
+{
+ struct ib_recv_wr *bad_recv_wr = NULL;
+ int rc;
+ u64 wr_id, temp_wr_id;
+ u32 index;
+
+ wr_id = ++link->wr_rx_id; /* tasklet context, thus not atomic */
+ temp_wr_id = wr_id;
+ index = do_div(temp_wr_id, link->wr_rx_cnt);
+ link->wr_rx_ibs[index].wr_id = wr_id;
+ rc = ib_post_recv(link->roce_qp, &link->wr_rx_ibs[index], &bad_recv_wr);
+ return rc;
+}
+
+int smc_wr_create_link(struct smc_link *);
+int smc_wr_alloc_link_mem(struct smc_link *);
+void smc_wr_free_link(struct smc_link *);
+void smc_wr_free_link_mem(struct smc_link *);
+void smc_wr_remember_qp_attr(struct smc_link *);
+void smc_wr_remove_dev(struct smc_ib_device *);
+void smc_wr_add_dev(struct smc_ib_device *);
+
+int smc_wr_tx_get_free_slot(struct smc_link *, smc_wr_tx_handler,
+ struct smc_wr_buf **,
+ struct smc_wr_tx_pend_priv **);
+int smc_wr_tx_put_slot(struct smc_link *, struct smc_wr_tx_pend_priv *);
+int smc_wr_tx_send(struct smc_link *, struct smc_wr_tx_pend_priv *);
+void smc_wr_tx_cq_handler(struct ib_cq *, void *);
+
+int smc_wr_rx_register_handler(struct smc_wr_rx_handler *);
+int smc_wr_rx_post_init(struct smc_link *);
+void smc_wr_rx_cq_handler(struct ib_cq *, void *);
+
+#endif /* SMC_WR_H */
--
2.8.4