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ib_srpt: Unregister sessions properly / fix RTU race (merged r4192 and r4193

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from trunk).


git-svn-id: http://svn.code.sf.net/p/scst/svn/branches/2.2.x@4195 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Bart Van Assche
2012-04-07 08:49:41 +00:00
parent 0d8b8df7e9
commit 9869575cc2
2 changed files with 34 additions and 72 deletions
Download Patch File Download Diff File Expand all files Collapse all files

104
srpt/src/ib_srpt.c
View File

@@ -153,7 +153,6 @@ static void srpt_unmap_sg_to_ib_sge(struct srpt_rdma_ch *ch,
struct srpt_send_ioctx *ioctx);
static void srpt_drain_channel(struct ib_cm_id *cm_id);
static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch);
static void srpt_free_ch(struct scst_session *sess);
static enum rdma_ch_state srpt_set_ch_state_to_disc(struct srpt_rdma_ch *ch)
{
@@ -351,8 +350,6 @@ static const char *get_ch_state_name(enum rdma_ch_state s)
return "disconnecting";
case CH_DRAINING:
return "draining";
case CH_FREEING:
return "freeing";
}
return "???";
}
@@ -2002,13 +1999,14 @@ static void srpt_completion(struct ib_cq *cq, void *ctx)
static int srpt_compl_thread(void *arg)
{
struct srpt_rdma_ch *ch;
struct srpt_device *sdev;
/* Hibernation / freezing of the SRPT kernel thread is not supported. */
current->flags |= PF_NOFREEZE;
ch = arg;
BUG_ON(!ch);
while (!kthread_should_stop() && !ch->last_wqe_received) {
while (!ch->last_wqe_received) {
set_current_state(TASK_INTERRUPTIBLE);
srpt_process_completion(ch->cq, ch, SCST_CONTEXT_THREAD,
SCST_CONTEXT_DIRECT);
@@ -2016,35 +2014,46 @@ static int srpt_compl_thread(void *arg)
}
set_current_state(TASK_RUNNING);
srpt_process_completion(ch->cq, ch, SCST_CONTEXT_THREAD,
SCST_CONTEXT_DIRECT);
/*
* Note: scst_unregister_session() must only be invoked after the last
* WQE event has been received.
* Process all IB (error) completions before invoking
* scst_unregister_session().
*/
TRACE_DBG("ch %s: about to invoke scst_unregister_session()",
ch->sess_name);
scst_unregister_session(ch->scst_sess, false, srpt_free_ch);
/*
* Some HCAs can queue send completions after the Last WQE
* event. Make sure to process these work completions.
*/
while (ch->state < CH_FREEING) {
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
srpt_process_completion(ch->cq, ch, SCST_CONTEXT_THREAD,
SCST_CONTEXT_DIRECT);
schedule();
if (atomic_read(&ch->scst_sess->sess_cmd_count) == 0)
break;
schedule_timeout(HZ / 10);
}
set_current_state(TASK_RUNNING);
TRACE_DBG("ch %s: about to invoke scst_unregister_session()",
ch->sess_name);
scst_unregister_session(ch->scst_sess, true, NULL);
sdev = ch->sport->sdev;
srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
sdev, ch->rq_size,
ch->max_rsp_size, DMA_TO_DEVICE);
spin_lock_irq(&sdev->spinlock);
list_del(&ch->list);
spin_unlock_irq(&sdev->spinlock);
ib_destroy_cm_id(ch->cm_id);
/*
* 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);
/* Avoid that wake_up_process() races with thread exit. */
spin_lock_irq(&ch->spinlock);
spin_unlock_irq(&ch->spinlock);
kfree(ch);
ch = NULL;
wake_up(&sdev->ch_releaseQ);
return 0;
}
@@ -2182,7 +2191,6 @@ static bool __srpt_close_ch(struct srpt_rdma_ch *ch)
break;
case CH_DISCONNECTING:
case CH_DRAINING:
case CH_FREEING:
break;
}
@@ -2230,42 +2238,6 @@ static void srpt_drain_channel(struct ib_cm_id *cm_id)
}
}
static void srpt_free_ch(struct scst_session *sess)
{
struct srpt_rdma_ch *ch;
struct srpt_device *sdev;
TRACE_ENTRY();
ch = scst_sess_get_tgt_priv(sess);
BUG_ON(ch->scst_sess != sess);
sdev = ch->sport->sdev;
BUG_ON(!sdev);
WARN_ON(!srpt_test_and_set_ch_state(ch, CH_DRAINING, CH_FREEING));
WARN_ON(!ch->last_wqe_received);
BUG_ON(!ch->thread);
BUG_ON(ch->thread == current);
srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
sdev, ch->rq_size,
ch->max_rsp_size, DMA_TO_DEVICE);
spin_lock_irq(&sdev->spinlock);
list_del(&ch->list);
spin_unlock_irq(&sdev->spinlock);
kthread_stop(ch->thread);
ch->thread = NULL;
kfree(ch);
wake_up(&sdev->ch_releaseQ);
TRACE_EXIT();
}
#if !defined(CONFIG_SCST_PROC)
/**
* srpt_enable_target() - Allows to enable a target via sysfs.
@@ -2591,7 +2563,8 @@ reject_and_release:
srpt_close_ch(ch);
out_keep_cm_id:
/*
* Tell the caller not to free cm_id since srpt_free_ch() will do that.
* Tell the caller not to free cm_id since srpt_compl_thread() will do
* that.
*/
ret = 0;
goto out;
@@ -2649,16 +2622,7 @@ static void srpt_cm_rtu_recv(struct ib_cm_id *cm_id)
BUG_ON(!ch);
if (srpt_test_and_set_ch_state(ch, CH_CONNECTING, CH_LIVE)) {
struct srpt_recv_ioctx *ioctx, *ioctx_tmp;
ret = srpt_ch_qp_rts(ch, ch->qp);
list_for_each_entry_safe(ioctx, ioctx_tmp, &ch->cmd_wait_list,
wait_list) {
list_del(&ioctx->wait_list);
srpt_handle_new_iu(ch, ioctx, NULL,
SCST_CONTEXT_THREAD);
}
if (ret)
srpt_close_ch(ch);
}
@@ -2717,7 +2681,7 @@ static void srpt_cm_drep_recv(struct ib_cm_id *cm_id)
* Note: srpt_cm_handler() must only return a non-zero value when transferring
* ownership of the cm_id to a channel if srpt_cm_req_recv() failed. Returning
* a non-zero value in any other case will trigger a race with the
* ib_destroy_cm_id() call in srpt_free_ch().
* ib_destroy_cm_id() call in srpt_compl_thread().
*/
static int srpt_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
{

2
srpt/src/ib_srpt.h
View File

@@ -272,14 +272,12 @@ struct srpt_send_ioctx {
* been sent and waiting for DREP or channel is being closed
* for another reason.
* @CH_DRAINING: QP is in ERR state.
* @CH_FREEING: QP resources are being freed.
*/
enum rdma_ch_state {
CH_CONNECTING,
CH_LIVE,
CH_DISCONNECTING,
CH_DRAINING,
CH_FREEING,
};
/**