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ib_srpt: Rework waiting for last WQE

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After having changed the queue pair state into "error", queue an additional
work request instead of waiting for the last WQE event.


git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@5357 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Bart Van Assche
2014-03-20 15:25:34 +00:00
parent 46aa72be44
commit fe6ad820db
2 changed files with 38 additions and 41 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
srpt/src/ib_srpt.c
View File

@@ -328,6 +328,8 @@ static const char *get_ch_state_name(enum rdma_ch_state s)
return "live";
case CH_DISCONNECTING:
return "disconnecting";
case CH_DISCONNECTED:
return "disconnected";
}
return "???";
}
@@ -337,8 +339,6 @@ static const char *get_ch_state_name(enum rdma_ch_state s)
*/
static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
{
unsigned long flags;
TRACE_DBG("QP event %d on cm_id=%p sess_name=%s state=%s",
event->event, ch->cm_id, ch->sess_name,
get_ch_state_name(ch->state));
@@ -356,11 +356,6 @@ static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
case IB_EVENT_QP_LAST_WQE_REACHED:
TRACE_DBG("%s, state %s: received Last WQE event.",
ch->sess_name, get_ch_state_name(ch->state));
BUG_ON(!ch->thread);
spin_lock_irqsave(&ch->spinlock, flags);
ch->last_wqe_received = true;
wake_up_process(ch->thread);
spin_unlock_irqrestore(&ch->spinlock, flags);
break;
default:
PRINT_ERROR("received unrecognized IB QP event %d",
@@ -982,6 +977,25 @@ out:
return ret;
}
/**
* srpt_zerolength_write() - Perform a zero-length RDMA write.
*
* A quote from the InfiniBand specification: C9-88: For an HCA responder
* using Reliable Connection service, for each zero-length RDMA READ or WRITE
* request, the R_Key shall not be validated, even if the request includes
* Immediate data.
*/
static int srpt_zerolength_write(struct srpt_rdma_ch *ch)
{
struct ib_send_wr wr, *bad_wr;
memset(&wr, 0, sizeof(wr));
wr.opcode = IB_WR_RDMA_WRITE;
wr.wr_id = encode_wr_id(SRPT_RDMA_ZEROLENGTH_WRITE, 0xffffffffUL);
wr.send_flags = IB_SEND_SIGNALED;
return ib_post_send(ch->qp, &wr, &bad_wr);
}
/**
* srpt_get_desc_tbl() - Parse the data descriptors of an SRP_CMD request.
* @ioctx: Pointer to the I/O context associated with the request.
@@ -1928,6 +1942,8 @@ static void srpt_process_send_completion(struct ib_cq *cq,
opcode == SRPT_RDMA_ABORT) {
srpt_handle_rdma_comp(ch, ch->ioctx_ring[index], opcode,
srpt_xmt_rsp_context);
} else if (opcode == SRPT_RDMA_ZEROLENGTH_WRITE) {
WARN_ON_ONCE(!srpt_set_ch_state(ch, CH_DISCONNECTED));
} else {
WARN(true, "unexpected opcode %d", opcode);
}
@@ -1945,6 +1961,8 @@ static void srpt_process_send_completion(struct ib_cq *cq,
" and cables.", opcode, index, wc->status);
srpt_handle_rdma_err_comp(ch, ch->ioctx_ring[index],
opcode, srpt_xmt_rsp_context);
} else if (opcode == SRPT_RDMA_ZEROLENGTH_WRITE) {
WARN_ON_ONCE(!srpt_set_ch_state(ch, CH_DISCONNECTED));
} else if (opcode != SRPT_RDMA_MID) {
WARN(true, "unexpected opcode %d", opcode);
}
@@ -2011,11 +2029,6 @@ static void srpt_free_ch(struct kref *kref)
{
struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref);
/*
* The function call below will wait for the completion handler
* callback to finish and hence ensures that wake_up_process() won't
* be invoked anymore from that callback for the current thread.
*/
srpt_destroy_ch_ib(ch);
kfree(ch);
@@ -2062,36 +2075,12 @@ static int srpt_compl_thread(void *arg)
ch = arg;
BUG_ON(!ch);
set_current_state(TASK_INTERRUPTIBLE);
#if defined(__GNUC__)
#if (__GNUC__ * 100 + __GNUC_MINOR__) <= 406
/* See also http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52925. */
barrier();
#endif
#endif
while (!ch->last_wqe_received && ch->state <= CH_LIVE) {
while (ch->state < CH_DISCONNECTED) {
set_current_state(TASK_INTERRUPTIBLE);
if (srpt_process_completion(ch, poll_budget) >= poll_budget)
cond_resched();
else
schedule();
set_current_state(TASK_INTERRUPTIBLE);
}
set_current_state(TASK_RUNNING);
/*
* Process all IB (error) completions before invoking
* scst_unregister_session().
*/
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
srpt_process_completion(ch, poll_budget);
if (atomic_read(&ch->scst_sess->sess_cmd_count) == 0)
break;
schedule_timeout(HZ / 10);
}
if (!ch->last_wqe_received) {
schedule_timeout(HZ);
srpt_process_completion(ch, poll_budget);
}
set_current_state(TASK_RUNNING);
@@ -2238,6 +2227,13 @@ static bool __srpt_close_ch(struct srpt_rdma_ch *ch)
PRINT_ERROR("%s: changing queue pair into error state"
" failed: %d", ch->sess_name, ret);
ret = srpt_zerolength_write(ch);
if (ret < 0) {
PRINT_ERROR("%s: queuing zero-length write failed: %d",
ch->sess_name, ret);
WARN_ON_ONCE(!srpt_set_ch_state(ch, CH_DISCONNECTED));
}
kref_put(&ch->kref, srpt_free_ch);
spin_lock_irq(&srpt_tgt->spinlock);
@@ -3168,7 +3164,7 @@ static int srpt_perform_rdmas(struct srpt_rdma_ch *ch,
}
PRINT_INFO("Waiting until RDMA abort finished [%d]",
ioctx->ioctx.index);
while (ch->state == CH_LIVE && !ioctx->rdma_aborted) {
while (ch->state < CH_DISCONNECTED && !ioctx->rdma_aborted) {
PRINT_INFO("Waiting until RDMA abort finished [%d]",
ioctx->ioctx.index);
msleep(1000);

5
srpt/src/ib_srpt.h
View File

@@ -147,6 +147,7 @@ enum srpt_opcode {
SRPT_RDMA_ABORT,
SRPT_RDMA_READ_LAST,
SRPT_RDMA_WRITE_LAST,
SRPT_RDMA_ZEROLENGTH_WRITE,
};
static inline u64 encode_wr_id(enum srpt_opcode opcode, u32 idx)
@@ -282,11 +283,13 @@ struct srpt_send_ioctx {
* @CH_DISCONNECTING: DREQ has been received and waiting for DREP or DREQ has
* been sent and waiting for DREP or channel is being closed
* for another reason.
* @CH_DISCONNECTED: Last WQE has been received.
*/
enum rdma_ch_state {
CH_CONNECTING,
CH_LIVE,
CH_DISCONNECTING,
CH_DISCONNECTED,
};
/**
@@ -317,7 +320,6 @@ enum rdma_ch_state {
* @wc: Work completion array.
* @state: channel state. See also enum rdma_ch_state.
* @processing_wait_list: Whether or not cmd_wait_list is being processed.
* @last_wqe_received: Whether the Last WQE QP event has been received.
* @list: Entry in srpt_nexus.ch_list;
* @cmd_wait_list: list of SCST commands that arrived before the RTU event. This
* list contains struct srpt_ioctx elements and is protected
@@ -351,7 +353,6 @@ struct srpt_rdma_ch {
struct list_head cmd_wait_list;
uint16_t pkey_index;
bool processing_wait_list;
bool last_wqe_received;
struct scst_session *scst_sess;
u8 sess_name[40];