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linux/net/smc/smc_wr.c

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/*
* 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 <linux/wait.h>
#include <rdma/ib_verbs.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) {
struct smc_link_group *lgr;
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);
}
/* terminate connections of this link group abnormally */
lgr = container_of(link, struct smc_link_group,
lnk[SMC_SINGLE_LINK]);
smc_lgr_terminate(lgr);
}
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) {
/* timeout - terminate connections */
struct smc_link_group *lgr;
lgr = container_of(link, struct smc_link_group,
lnk[SMC_SINGLE_LINK]);
smc_lgr_terminate(lgr);
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;
}
void smc_wr_tx_dismiss_slots(struct smc_link *link, u8 wr_rx_hdr_type,
smc_wr_tx_filter filter,
smc_wr_tx_dismisser dismisser,
unsigned long data)
{
struct smc_wr_tx_pend_priv *tx_pend;
struct smc_wr_rx_hdr *wr_rx;
int i;
for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
wr_rx = (struct smc_wr_rx_hdr *)&link->wr_rx_bufs[i];
if (wr_rx->type != wr_rx_hdr_type)
continue;
tx_pend = &link->wr_tx_pends[i].priv;
if (filter(tx_pend, data))
dismisser(tx_pend);
}
}
bool smc_wr_tx_has_pending(struct smc_link *link, u8 wr_rx_hdr_type,
smc_wr_tx_filter filter, unsigned long data)
{
struct smc_wr_tx_pend_priv *tx_pend;
struct smc_wr_rx_hdr *wr_rx;
int i;
for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
wr_rx = (struct smc_wr_rx_hdr *)&link->wr_rx_bufs[i];
if (wr_rx->type != wr_rx_hdr_type)
continue;
tx_pend = &link->wr_tx_pends[i].priv;
if (filter(tx_pend, data))
return true;
}
return false;
}
/****************************** 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 {
struct smc_link_group *lgr;
/* 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:
/* terminate connections of this link group
* abnormally
*/
lgr = container_of(link, struct smc_link_group,
lnk[SMC_SINGLE_LINK]);
smc_lgr_terminate(lgr);
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_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
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_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
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;
}
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