[PATCH 5/9] srpt: use the new CQ API

Christoph Hellwig
2015-11-13T13:53:29Z

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/infiniband/ulp/srpt/ib_srpt.c | 327 +++++++++-------------------------
drivers/infiniband/ulp/srpt/ib_srpt.h | 28 +--
2 files changed, 88 insertions(+), 267 deletions(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 2b6dd71..d4bbad3 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -95,6 +95,8 @@ MODULE_PARM_DESC(srpt_service_guid,
static struct ib_client srpt_client;
static void srpt_release_channel(struct srpt_rdma_ch *ch);
static int srpt_queue_status(struct se_cmd *cmd);
+static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc);
+static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc);

/**
* opposite_dma_dir() - Swap DMA_TO_DEVICE and DMA_FROM_DEVICE.
@@ -780,12 +782,12 @@ static int srpt_post_recv(struct srpt_device *sdev,
struct ib_recv_wr wr, *bad_wr;

BUG_ON(!sdev);
- wr.wr_id = encode_wr_id(SRPT_RECV, ioctx->ioctx.index);
-
list.addr = ioctx->ioctx.dma;
list.length = srp_max_req_size;
list.lkey = sdev->pd->local_dma_lkey;

+ ioctx->ioctx.cqe.done = srpt_recv_done;
+ wr.wr_cqe = &ioctx->ioctx.cqe;
wr.next = NULL;
wr.sg_list = &list;
wr.num_sge = 1;
@@ -821,8 +823,9 @@ static int srpt_post_send(struct srpt_rdma_ch *ch,
list.length = len;
list.lkey = sdev->pd->local_dma_lkey;

+ ioctx->ioctx.cqe.done = srpt_send_done;
wr.next = NULL;
- wr.wr_id = encode_wr_id(SRPT_SEND, ioctx->ioctx.index);
+ wr.wr_cqe = &ioctx->ioctx.cqe;
wr.sg_list = &list;
wr.num_sge = 1;
wr.opcode = IB_WR_SEND;
@@ -1385,116 +1388,44 @@ out:
}

/**
- * srpt_handle_send_err_comp() - Process an IB_WC_SEND error completion.
- */
-static void srpt_handle_send_err_comp(struct srpt_rdma_ch *ch, u64 wr_id)
-{
- struct srpt_send_ioctx *ioctx;
- enum srpt_command_state state;
- u32 index;
-
- atomic_inc(&ch->sq_wr_avail);
-
- index = idx_from_wr_id(wr_id);
- ioctx = ch->ioctx_ring[index];
- state = srpt_get_cmd_state(ioctx);
-
- WARN_ON(state != SRPT_STATE_CMD_RSP_SENT
- && state != SRPT_STATE_MGMT_RSP_SENT
- && state != SRPT_STATE_NEED_DATA
- && state != SRPT_STATE_DONE);
-
- /* If SRP_RSP sending failed, undo the ch->req_lim change. */
- if (state == SRPT_STATE_CMD_RSP_SENT
- || state == SRPT_STATE_MGMT_RSP_SENT)
- atomic_dec(&ch->req_lim);
-
- srpt_abort_cmd(ioctx);
-}
-
-/**
- * srpt_handle_send_comp() - Process an IB send completion notification.
- */
-static void srpt_handle_send_comp(struct srpt_rdma_ch *ch,
- struct srpt_send_ioctx *ioctx)
-{
- enum srpt_command_state state;
-
- atomic_inc(&ch->sq_wr_avail);
-
- state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
-
- if (WARN_ON(state != SRPT_STATE_CMD_RSP_SENT
- && state != SRPT_STATE_MGMT_RSP_SENT
- && state != SRPT_STATE_DONE))
- pr_debug("state = %d\n", state);
-
- if (state != SRPT_STATE_DONE) {
- srpt_unmap_sg_to_ib_sge(ch, ioctx);
- transport_generic_free_cmd(&ioctx->cmd, 0);
- } else {
- pr_err("IB completion has been received too late for"
- " wr_id = %u.\n", ioctx->ioctx.index);
- }
-}
-
-/**
- * srpt_handle_rdma_comp() - Process an IB RDMA completion notification.
- *
* XXX: what is now target_execute_cmd used to be asynchronous, and unmapping
* the data that has been transferred via IB RDMA had to be postponed until the
* check_stop_free() callback. None of this is necessary anymore and needs to
* be cleaned up.
*/
-static void srpt_handle_rdma_comp(struct srpt_rdma_ch *ch,
- struct srpt_send_ioctx *ioctx,
- enum srpt_opcode opcode)
+static void srpt_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc)
{
+ struct srpt_rdma_ch *ch = cq->cq_context;
+ struct srpt_send_ioctx *ioctx =
+ container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);
+
WARN_ON(ioctx->n_rdma <= 0);
atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);

- if (opcode == SRPT_RDMA_READ_LAST) {
- if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
- SRPT_STATE_DATA_IN))
- target_execute_cmd(&ioctx->cmd);
- else
- pr_err("%s[%d]: wrong state = %d\n", __func__,
- __LINE__, srpt_get_cmd_state(ioctx));
- } else {
- WARN(true, "unexpected opcode %d\n", opcode);
+ if (unlikely(wc->status != IB_WC_SUCCESS)) {
+ pr_info("RDMA_READ for ioctx 0x%p failed with status %d\n",
+ ioctx, wc->status);
+ srpt_abort_cmd(ioctx);
+ return;
}
+
+ if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
+ SRPT_STATE_DATA_IN))
+ target_execute_cmd(&ioctx->cmd);
+ else
+ pr_err("%s[%d]: wrong state = %d\n", __func__,
+ __LINE__, srpt_get_cmd_state(ioctx));
}

-/**
- * srpt_handle_rdma_err_comp() - Process an IB RDMA error completion.
- */
-static void srpt_handle_rdma_err_comp(struct srpt_rdma_ch *ch,
- struct srpt_send_ioctx *ioctx,
- enum srpt_opcode opcode)
+static void srpt_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc)
{
- enum srpt_command_state state;
+ struct srpt_send_ioctx *ioctx =
+ container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);

- state = srpt_get_cmd_state(ioctx);
- switch (opcode) {
- case SRPT_RDMA_READ_LAST:
- if (ioctx->n_rdma <= 0) {
- pr_err("Received invalid RDMA read"
- " error completion with idx %d\n",
- ioctx->ioctx.index);
- break;
- }
- atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
- if (state == SRPT_STATE_NEED_DATA)
- srpt_abort_cmd(ioctx);
- else
- pr_err("%s[%d]: wrong state = %d\n",
- __func__, __LINE__, state);
- break;
- case SRPT_RDMA_WRITE_LAST:
- break;
- default:
- pr_err("%s[%d]: opcode = %u\n", __func__, __LINE__, opcode);
- break;
+ if (unlikely(wc->status != IB_WC_SUCCESS)) {
+ pr_info("RDMA_WRITE for ioctx 0x%p failed with status %d\n",
+ ioctx, wc->status);
+ srpt_abort_cmd(ioctx);
}
}

@@ -1929,32 +1860,26 @@ out:
return;
}

-static void srpt_process_rcv_completion(struct ib_cq *cq,
- struct srpt_rdma_ch *ch,
- struct ib_wc *wc)
+static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc)
{
- struct srpt_device *sdev = ch->sport->sdev;
- struct srpt_recv_ioctx *ioctx;
- u32 index;
+ struct srpt_rdma_ch *ch = cq->cq_context;
+ struct srpt_recv_ioctx *ioctx =
+ container_of(wc->wr_cqe, struct srpt_recv_ioctx, ioctx.cqe);

- index = idx_from_wr_id(wc->wr_id);
if (wc->status == IB_WC_SUCCESS) {
int req_lim;

req_lim = atomic_dec_return(&ch->req_lim);
if (unlikely(req_lim < 0))
pr_err("req_lim = %d < 0\n", req_lim);
- ioctx = sdev->ioctx_ring[index];
srpt_handle_new_iu(ch, ioctx, NULL);
} else {
- pr_info("receiving failed for idx %u with status %d\n",
- index, wc->status);
+ pr_info("receiving failed for ioctx %p with status %d\n",
+ ioctx, wc->status);
}
}

/**
- * srpt_process_send_completion() - Process an IB send completion.
- *
* Note: Although this has not yet been observed during tests, at least in
* theory it is possible that the srpt_get_send_ioctx() call invoked by
* srpt_handle_new_iu() fails. This is possible because the req_lim_delta
@@ -1967,108 +1892,52 @@ static void srpt_process_rcv_completion(struct ib_cq *cq,
* are queued on cmd_wait_list. The code below processes these delayed
* requests one at a time.
*/
-static void srpt_process_send_completion(struct ib_cq *cq,
- struct srpt_rdma_ch *ch,
- struct ib_wc *wc)
+static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc)
{
- struct srpt_send_ioctx *send_ioctx;
- uint32_t index;
- enum srpt_opcode opcode;
+ struct srpt_rdma_ch *ch = cq->cq_context;
+ struct srpt_send_ioctx *ioctx =
+ container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);
+ enum srpt_command_state state;
+
+ state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);

- index = idx_from_wr_id(wc->wr_id);
- opcode = opcode_from_wr_id(wc->wr_id);
- send_ioctx = ch->ioctx_ring[index];
- if (wc->status == IB_WC_SUCCESS) {
- if (opcode == SRPT_SEND)
- srpt_handle_send_comp(ch, send_ioctx);
- else {
- WARN_ON(wc->opcode != IB_WC_RDMA_READ);
- srpt_handle_rdma_comp(ch, send_ioctx, opcode);
- }
+ WARN_ON(state != SRPT_STATE_CMD_RSP_SENT &&
+ state != SRPT_STATE_MGMT_RSP_SENT);
+
+ atomic_inc(&ch->sq_wr_avail);
+
+ if (wc->status != IB_WC_SUCCESS) {
+ pr_info("sending response for ioctx 0x%p failed"
+ " with status %d\n", ioctx, wc->status);
+
+ atomic_dec(&ch->req_lim);
+ srpt_abort_cmd(ioctx);
+ goto out;
+ }
+
+ if (state != SRPT_STATE_DONE) {
+ srpt_unmap_sg_to_ib_sge(ch, ioctx);
+ transport_generic_free_cmd(&ioctx->cmd, 0);
} else {
- if (opcode == SRPT_SEND) {
- pr_info("sending response for idx %u failed"
- " with status %d\n", index, wc->status);
- srpt_handle_send_err_comp(ch, wc->wr_id);
- } else if (opcode != SRPT_RDMA_MID) {
- pr_info("RDMA t %d for idx %u failed with"
- " status %d\n", opcode, index, wc->status);
- srpt_handle_rdma_err_comp(ch, send_ioctx, opcode);
- }
+ pr_err("IB completion has been received too late for"
+ " wr_id = %u.\n", ioctx->ioctx.index);
}

- while (unlikely(opcode == SRPT_SEND
- && !list_empty(&ch->cmd_wait_list)
- && srpt_get_ch_state(ch) == CH_LIVE
- && (send_ioctx = srpt_get_send_ioctx(ch)) != NULL)) {
+out:
+ while (!list_empty(&ch->cmd_wait_list) &&
+ srpt_get_ch_state(ch) == CH_LIVE &&
+ (ioctx = srpt_get_send_ioctx(ch)) != NULL) {
struct srpt_recv_ioctx *recv_ioctx;

recv_ioctx = list_first_entry(&ch->cmd_wait_list,
struct srpt_recv_ioctx,
wait_list);
list_del(&recv_ioctx->wait_list);
- srpt_handle_new_iu(ch, recv_ioctx, send_ioctx);
- }
-}
-
-static void srpt_process_completion(struct ib_cq *cq, struct srpt_rdma_ch *ch)
-{
- struct ib_wc *const wc = ch->wc;
- int i, n;
-
- WARN_ON(cq != ch->cq);
-
- ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
- while ((n = ib_poll_cq(cq, ARRAY_SIZE(ch->wc), wc)) > 0) {
- for (i = 0; i < n; i++) {
- if (opcode_from_wr_id(wc[i].wr_id) == SRPT_RECV)
- srpt_process_rcv_completion(cq, ch, &wc[i]);
- else
- srpt_process_send_completion(cq, ch, &wc[i]);
- }
+ srpt_handle_new_iu(ch, recv_ioctx, ioctx);
}
}

/**
- * srpt_completion() - IB completion queue callback function.
- *
- * Notes:
- * - It is guaranteed that a completion handler will never be invoked
- * concurrently on two different CPUs for the same completion queue. See also
- * Documentation/infiniband/core_locking.txt and the implementation of
- * handle_edge_irq() in kernel/irq/chip.c.
- * - When threaded IRQs are enabled, completion handlers are invoked in thread
- * context instead of interrupt context.
- */
-static void srpt_completion(struct ib_cq *cq, void *ctx)
-{
- struct srpt_rdma_ch *ch = ctx;
-
- wake_up_interruptible(&ch->wait_queue);
-}
-
-static int srpt_compl_thread(void *arg)
-{
- struct srpt_rdma_ch *ch;
-
- /* Hibernation / freezing of the SRPT kernel thread is not supported. */
- current->flags |= PF_NOFREEZE;
-
- ch = arg;
- BUG_ON(!ch);
- pr_info("Session %s: kernel thread %s (PID %d) started\n",
- ch->sess_name, ch->thread->comm, current->pid);
- while (!kthread_should_stop()) {
- wait_event_interruptible(ch->wait_queue,
- (srpt_process_completion(ch->cq, ch),
- kthread_should_stop()));
- }
- pr_info("Session %s: kernel thread %s (PID %d) stopped\n",
- ch->sess_name, ch->thread->comm, current->pid);
- return 0;
-}
-
-/**
* srpt_create_ch_ib() - Create receive and send completion queues.
*/
static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
@@ -2077,7 +1946,6 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
struct srpt_port *sport = ch->sport;
struct srpt_device *sdev = sport->sdev;
u32 srp_sq_size = sport->port_attrib.srp_sq_size;
- struct ib_cq_init_attr cq_attr = {};
int ret;

WARN_ON(ch->rq_size < 1);
@@ -2088,9 +1956,8 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
goto out;

retry:
- cq_attr.cqe = ch->rq_size + srp_sq_size;
- ch->cq = ib_create_cq(sdev->device, srpt_completion, NULL, ch,
- &cq_attr);
+ ch->cq = ib_alloc_cq(sdev->device, ch, ch->rq_size + srp_sq_size,
+ 0 /* XXX: spread CQs */, IB_POLL_WORKQUEUE);
if (IS_ERR(ch->cq)) {
ret = PTR_ERR(ch->cq);
pr_err("failed to create CQ cqe= %d ret= %d\n",
@@ -2133,18 +2000,6 @@ retry:
if (ret)
goto err_destroy_qp;

- init_waitqueue_head(&ch->wait_queue);
-
- pr_debug("creating thread for session %s\n", ch->sess_name);
-
- ch->thread = kthread_run(srpt_compl_thread, ch, "ib_srpt_compl");
- if (IS_ERR(ch->thread)) {
- pr_err("failed to create kernel thread %ld\n",
- PTR_ERR(ch->thread));
- ch->thread = NULL;
- goto err_destroy_qp;
- }
-
out:
kfree(qp_init);
return ret;
@@ -2152,17 +2007,14 @@ out:
err_destroy_qp:
ib_destroy_qp(ch->qp);
err_destroy_cq:
- ib_destroy_cq(ch->cq);
+ ib_free_cq(ch->cq);
goto out;
}

static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
{
- if (ch->thread)
- kthread_stop(ch->thread);
-
ib_destroy_qp(ch->qp);
- ib_destroy_cq(ch->cq);
+ ib_free_cq(ch->cq);
}

/**
@@ -2824,9 +2676,7 @@ static int srpt_perform_rdmas(struct srpt_rdma_ch *ch,
struct srpt_send_ioctx *ioctx)
{
struct ib_send_wr *bad_wr;
- int i;
- int ret;
- int sq_wr_avail;
+ int sq_wr_avail, ret, i;
enum dma_data_direction dir;
const int n_rdma = ioctx->n_rdma;

@@ -2843,29 +2693,24 @@ static int srpt_perform_rdmas(struct srpt_rdma_ch *ch,
}

for (i = 0; i < n_rdma; i++) {
- struct ib_rdma_wr *wr = &ioctx->rdma_ius[i];
-
- if (dir == DMA_FROM_DEVICE) {
- wr->wr.opcode = IB_WR_RDMA_WRITE;
- wr->wr.wr_id = encode_wr_id(i == n_rdma - 1 ?
- SRPT_RDMA_WRITE_LAST :
- SRPT_RDMA_MID,
- ioctx->ioctx.index);
- } else {
- wr->wr.opcode = IB_WR_RDMA_READ;
- wr->wr.wr_id = encode_wr_id(i == n_rdma - 1 ?
- SRPT_RDMA_READ_LAST :
- SRPT_RDMA_MID,
- ioctx->ioctx.index);
- }
+ struct ib_send_wr *wr = &ioctx->rdma_ius[i].wr;
+
+ wr->opcode = (dir == DMA_FROM_DEVICE) ?
+ IB_WR_RDMA_WRITE : IB_WR_RDMA_READ;

if (i == n_rdma - 1) {
/* only get completion event for the last rdma read */
- if (dir == DMA_TO_DEVICE)
- wr->wr.send_flags = IB_SEND_SIGNALED;
- wr->wr.next = NULL;
+ if (dir == DMA_TO_DEVICE) {
+ wr->send_flags = IB_SEND_SIGNALED;
+ ioctx->rdma_cqe.done = srpt_rdma_read_done;
+ } else {
+ ioctx->rdma_cqe.done = srpt_rdma_write_done;
+ }
+ wr->wr_cqe = &ioctx->rdma_cqe;
+ wr->next = NULL;
} else {
- wr->wr.next = &ioctx->rdma_ius[i + 1].wr;
+ wr->wr_cqe = NULL;
+ wr->next = &ioctx->rdma_ius[i + 1].wr;
}
}

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h
index fd6097e..f9568f5 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.h
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.h
@@ -128,27 +128,6 @@ enum {
DEFAULT_MAX_RDMA_SIZE = 65536,
};

-enum srpt_opcode {
- SRPT_RECV,
- SRPT_SEND,
- SRPT_RDMA_MID,
- SRPT_RDMA_READ_LAST,
- SRPT_RDMA_WRITE_LAST,
-};
-
-static inline u64 encode_wr_id(u8 opcode, u32 idx)
-{
- return ((u64)opcode << 32) | idx;
-}
-static inline enum srpt_opcode opcode_from_wr_id(u64 wr_id)
-{
- return wr_id >> 32;
-}
-static inline u32 idx_from_wr_id(u64 wr_id)
-{
- return (u32)wr_id;
-}
-
/**
* enum srpt_command_state - SCSI command state managed by SRPT.
* @SRPT_STATE_NEW: New command arrived and is being processed.
@@ -180,6 +159,7 @@ enum srpt_command_state {
* @index: Index of the I/O context in its ioctx_ring array.
*/
struct srpt_ioctx {
+ struct ib_cqe cqe;
void *buf;
dma_addr_t dma;
uint32_t index;
@@ -218,6 +198,7 @@ struct srpt_send_ioctx {
struct srpt_ioctx ioctx;
struct srpt_rdma_ch *ch;
struct ib_rdma_wr *rdma_ius;
+ struct ib_cqe rdma_cqe;
struct srp_direct_buf *rbufs;
struct srp_direct_buf single_rbuf;
struct scatterlist *sg;
@@ -255,9 +236,6 @@ enum rdma_ch_state {

/**
* struct srpt_rdma_ch - RDMA channel.
- * @wait_queue: Allows the kernel thread to wait for more work.
- * @thread: Kernel thread that processes the IB queues associated with
- * the channel.
* @cm_id: IB CM ID associated with the channel.
* @qp: IB queue pair used for communicating over this channel.
* @cq: IB completion queue for this channel.
@@ -287,8 +265,6 @@ enum rdma_ch_state {
* @release_done: Enables waiting for srpt_release_channel() completion.
*/
struct srpt_rdma_ch {
- wait_queue_head_t wait_queue;
- struct task_struct *thread;
struct ib_cm_id *cm_id;
struct ib_qp *qp;
struct ib_cq *cq;
--
1.9.1