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iscsi-scst: Move old TM response dropping to preparing new response stage

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The second TM request can come while the old one, response for which is
going to be delayed, is still being processed, hence no response
prepared yet, so the delayed response should be dropped on the stage of
the new response preparing. Otherwise in this place the old delayed
response will trigger BUG_ON().



git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@6456 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Vladislav Bolkhovitin
2015-07-31 01:09:58 +00:00
parent 06ef46415c
commit e5e54f312b
3 changed files with 44 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

61
iscsi-scst/kernel/iscsi.c
View File

@@ -2610,6 +2610,26 @@ again:
return;
}
/*
* Drops, but not releases(!) delayed TM response.
* sn_lock supposed to be held on entry.
*/
void iscsi_drop_delayed_tm_rsp(struct iscsi_cmnd *tm_rsp)
{
struct iscsi_conn *conn = tm_rsp->conn;
struct iscsi_session *sess = conn->session;
TRACE_ENTRY();
TRACE_MGMT_DBG("Dropping delayed TM rsp %p", tm_rsp);
sess->tm_rsp = NULL;
sess->tm_active--;
sBUG_ON(sess->tm_active < 0);
TRACE_EXIT();
return;
}
static void execute_task_management(struct iscsi_cmnd *req)
{
struct iscsi_conn *conn = req->conn;
@@ -2630,21 +2650,7 @@ static void execute_task_management(struct iscsi_cmnd *req)
spin_lock(&sess->sn_lock);
sess->tm_active++;
sess->tm_sn = req_hdr->cmd_sn;
if (sess->tm_rsp != NULL) {
struct iscsi_cmnd *tm_rsp = sess->tm_rsp;
TRACE_MGMT_DBG("Dropping delayed TM rsp %p", tm_rsp);
sess->tm_rsp = NULL;
sess->tm_active--;
spin_unlock(&sess->sn_lock);
sBUG_ON(sess->tm_active < 0);
rsp_cmnd_release(tm_rsp);
} else
spin_unlock(&sess->sn_lock);
spin_unlock(&sess->sn_lock);
scst_rx_mgmt_params_init(&params);
@@ -3593,6 +3599,11 @@ static bool iscsi_is_delay_tm_resp(struct iscsi_cmnd *rsp)
/* This should be checked for immediate TM commands as well */
#if 0
if (((scst_random() % 10) == 2))
res = 1;
#endif
switch (function) {
default:
if (before(sess->exp_cmd_sn, req_hdr->cmd_sn))
@@ -3684,9 +3695,22 @@ static void iscsi_send_task_mgmt_resp(struct iscsi_cmnd *req, int status,
rsp->should_close_all_conn = 1;
}
sBUG_ON(sess->tm_rsp != NULL);
again:
spin_lock(&sess->sn_lock);
if (sess->tm_rsp != NULL) {
struct iscsi_cmnd *old_tm_rsp = sess->tm_rsp;
/*
* It is assumed that if we have another TM request, the
* original command the delayed TM response is waiting for
* is not going to come, hence we can drop it.
*/
iscsi_drop_delayed_tm_rsp(old_tm_rsp);
spin_unlock(&sess->sn_lock);
rsp_cmnd_release(old_tm_rsp);
goto again;
}
if (iscsi_is_delay_tm_resp(rsp)) {
TRACE_MGMT_DBG("Delaying TM fn %d response %p "
"(req %p), because not all affected commands "
@@ -3698,9 +3722,8 @@ static void iscsi_send_task_mgmt_resp(struct iscsi_cmnd *req, int status,
goto out_release;
}
sess->tm_active--;
spin_unlock(&sess->sn_lock);
sBUG_ON(sess->tm_active < 0);
spin_unlock(&sess->sn_lock);
iscsi_cmnd_init_write(rsp, ISCSI_INIT_WRITE_WAKE);

1
iscsi-scst/kernel/iscsi.h
View File

@@ -548,6 +548,7 @@ extern void cmnd_tx_start(struct iscsi_cmnd *);
extern void cmnd_tx_end(struct iscsi_cmnd *);
extern void req_cmnd_release_force(struct iscsi_cmnd *req);
extern void rsp_cmnd_release(struct iscsi_cmnd *);
extern void iscsi_drop_delayed_tm_rsp(struct iscsi_cmnd *tm_rsp);
extern void cmnd_done(struct iscsi_cmnd *cmnd);
extern void conn_abort(struct iscsi_conn *conn);
extern void iscsi_restart_cmnd(struct iscsi_cmnd *cmnd);

5
iscsi-scst/kernel/nthread.c
View File

@@ -459,10 +459,7 @@ static void close_conn(struct iscsi_conn *conn)
spin_lock(&session->sn_lock);
if (session->tm_rsp && session->tm_rsp->conn == conn) {
struct iscsi_cmnd *tm_rsp = session->tm_rsp;
TRACE_MGMT_DBG("Dropping delayed TM rsp %p", tm_rsp);
session->tm_rsp = NULL;
session->tm_active--;
WARN_ON(session->tm_active < 0);
iscsi_drop_delayed_tm_rsp(tm_rsp);
spin_unlock(&session->sn_lock);
mutex_unlock(&target->target_mutex);