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ib_srpt: Fix a (hard to trigger) race with regard to SRP login.

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git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@3532 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Bart Van Assche
2011-06-04 14:32:22 +00:00
parent bc913e9258
commit b9f4ee7bc8
1 changed files with 38 additions and 40 deletions
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78
srpt/src/ib_srpt.c
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@@ -186,6 +186,26 @@ srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new_state)
return prev;
}
static enum rdma_ch_state srpt_set_ch_state_to_disc(struct srpt_rdma_ch *ch)
{
unsigned long flags;
enum rdma_ch_state prev;
spin_lock_irqsave(&ch->spinlock, flags);
prev = ch->state;
switch (prev) {
case CH_CONNECTING:
case CH_LIVE:
ch->state = CH_DISCONNECTING;
break;
default:
break;
}
spin_unlock_irqrestore(&ch->spinlock, flags);
return prev;
}
static bool srpt_set_ch_state_to_draining(struct srpt_rdma_ch *ch)
{
unsigned long flags;
@@ -2017,27 +2037,21 @@ static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
* Reset the QP and make sure all resources associated with the channel will
* be deallocated at an appropriate time.
*
* Returns true if and only if the channel state has been modified from
* CH_CONNECTING or CH_LIVE into CH_DISCONNECTING.
*
* Note: The caller must hold ch->sport->sdev->spinlock.
*/
static void __srpt_close_ch(struct srpt_rdma_ch *ch)
static bool __srpt_close_ch(struct srpt_rdma_ch *ch)
{
struct srpt_device *sdev;
enum rdma_ch_state prev_state;
unsigned long flags;
bool was_live;
sdev = ch->sport->sdev;
was_live = false;
spin_lock_irqsave(&ch->spinlock, flags);
prev_state = ch->state;
switch (prev_state) {
case CH_CONNECTING:
case CH_LIVE:
ch->state = CH_DISCONNECTING;
break;
default:
break;
}
spin_unlock_irqrestore(&ch->spinlock, flags);
prev_state = srpt_set_ch_state_to_disc(ch);
switch (prev_state) {
case CH_CONNECTING:
@@ -2045,6 +2059,7 @@ static void __srpt_close_ch(struct srpt_rdma_ch *ch)
NULL, 0);
/* fall through */
case CH_LIVE:
was_live = true;
if (ib_send_cm_dreq(ch->cm_id, NULL, 0) < 0)
PRINT_ERROR("%s", "sending CM DREQ failed.");
break;
@@ -2053,6 +2068,8 @@ static void __srpt_close_ch(struct srpt_rdma_ch *ch)
case CH_RELEASING:
break;
}
return was_live;
}
/**
@@ -2340,19 +2357,11 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
&& param->port == ch->sport->port
&& param->listen_id == ch->sport->sdev->cm_id
&& ch->cm_id) {
enum rdma_ch_state ch_state;
ch_state = ch->state;
if (ch_state != CH_CONNECTING &&
ch_state != CH_LIVE)
if (!__srpt_close_ch(ch))
continue;
/* found an existing channel */
TRACE_DBG("Found existing channel name= %s"
" cm_id= %p state= %d",
ch->sess_name, ch->cm_id, ch_state);
__srpt_close_ch(ch);
TRACE_DBG("Found existing channel %s; cm_id ="
" %p", ch->sess_name, ch->cm_id);
rsp->rsp_flags =
SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
@@ -2600,8 +2609,6 @@ static void srpt_cm_rep_error(struct ib_cm_id *cm_id)
static void srpt_cm_dreq_recv(struct ib_cm_id *cm_id)
{
struct srpt_rdma_ch *ch;
unsigned long flags;
bool send_drep = false;
ch = srpt_find_channel(cm_id->context, cm_id);
if (!ch) {
@@ -2610,27 +2617,18 @@ static void srpt_cm_dreq_recv(struct ib_cm_id *cm_id)
goto out;
}
spin_lock_irqsave(&ch->spinlock, flags);
switch (ch->state) {
switch (srpt_set_ch_state_to_disc(ch)) {
case CH_CONNECTING:
case CH_LIVE:
send_drep = true;
ch->state = CH_DISCONNECTING;
break;
case CH_DISCONNECTING:
case CH_DRAINING:
case CH_RELEASING:
__WARN();
break;
}
spin_unlock_irqrestore(&ch->spinlock, flags);
if (send_drep) {
if (ib_send_cm_drep(ch->cm_id, NULL, 0) >= 0)
PRINT_INFO("Received DREQ and sent DREP for session %s",
ch->sess_name);
else
PRINT_ERROR("%s", "Sending DREP failed");
break;
default:
__WARN();
break;
}
out:
;