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- Fixed race with wake_up()

Browse Source 
- Some cleanups


git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@129 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Vladislav Bolkhovitin
2007-06-15 09:02:57 +00:00
parent 24922d550c
commit c7748b916b
2 changed files with 49 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files
qla2x00t/qla2x00-target/qla2x00t.c
+47 -24
View File
@@ -123,7 +123,20 @@ static struct qla2x_tgt_target tgt_data;
static inline int test_tgt_sess_count(struct q2t_tgt *tgt, scsi_qla_host_t *ha)
{
return (atomic_read(&tgt->sess_count) == 0);
unsigned long flags;
int res;
/*
* We need to protect against race, when tgt is freed before or
* inside wake_up()
*/
spin_lock_irqsave(&tgt->ha->hardware_lock, flags);
TRACE_DBG("tgt %p, empty(sess_list)=%d sess_count=%d",
tgt, list_empty(&tgt->sess_list), tgt->sess_count);
res = (tgt->sess_count == 0);
spin_unlock_irqrestore(&tgt->ha->hardware_lock, flags);
return res;
}
/* ha->hardware_lock supposed to be held on entry */
@@ -270,6 +283,8 @@ static void q2t_free_session_done(struct scst_session *scst_sess)
{
struct q2t_sess *sess;
struct q2t_tgt *tgt;
scsi_qla_host_t *ha;
unsigned long flags;
TRACE_ENTRY();
@@ -284,11 +299,19 @@ static void q2t_free_session_done(struct scst_session *scst_sess)
goto out;
TRACE_MGMT_DBG("tgt->handle %x empty(sess_list) %d sess_count %d",
tgt->handle, list_empty(&tgt->sess_list),
atomic_read(&tgt->sess_count));
tgt->handle, list_empty(&tgt->sess_list), tgt->sess_count);
if (atomic_dec_and_test(&tgt->sess_count))
ha = tgt->ha;
/*
* We need to protect against race, when tgt is freed before or
* inside wake_up()
*/
spin_lock_irqsave(&ha->hardware_lock, flags);
tgt->sess_count--;
if (tgt->sess_count == 0)
wake_up_all(&tgt->waitQ);
spin_unlock_irqrestore(&ha->hardware_lock, flags);
out:
TRACE_EXIT();
@@ -380,9 +403,10 @@ static int q2t_target_release(struct scst_tgt *scst_tgt)
TRACE_MGMT_DBG("Finished waiting for tgt %p: empty(sess_list)=%d "
"sess_count=%d", tgt, list_empty(&tgt->sess_list),
atomic_read(&tgt->sess_count));
tgt->sess_count);
scst_tgt_set_tgt_priv(scst_tgt, NULL);
ha->tgt = NULL;
kfree(tgt);
@@ -1134,7 +1158,7 @@ static void q2t_ctio_completion(scsi_qla_host_t *ha, uint32_t handle)
q2t_do_ctio_completion(ha, handle,
CTIO_SUCCESS, NULL);
} else {
TRACE_DBG("CTIO but target mode not enabled. ha %p handle %#x",
TRACE_DBG("CTIO, but target mode not enabled. ha %p handle %#x",
ha, handle);
}
TRACE_EXIT();
@@ -1347,8 +1371,8 @@ static int q2t_send_cmd_to_scst(scsi_qla_host_t *ha, atio_entry_t *atio)
if (tgt->tgt_shutdown) {
TRACE_DBG("New command while the device %p is shutting down",
tgt);
TRACE_MGMT_DBG("New command while device %p is shutting "
"down", tgt);
res = -EFAULT;
goto out;
}
@@ -1415,7 +1439,7 @@ static int q2t_send_cmd_to_scst(scsi_qla_host_t *ha, atio_entry_t *atio)
/* add session data to host data structure */
list_add(&sess->list, &tgt->sess_list);
atomic_inc(&tgt->sess_count);
tgt->sess_count++;
}
cmd->sess = sess;
@@ -1429,7 +1453,8 @@ out:
out_free_sess:
kfree(sess);
if (atomic_dec_and_test(&tgt->sess_count))
tgt->sess_count--;
if (tgt->sess_count == 0)
wake_up_all(&tgt->waitQ);
/* go through */
@@ -1765,14 +1790,16 @@ static void q2t_response_pkt(scsi_qla_host_t *ha, sts_entry_t *pkt)
q2t_send_term_exchange(ha, NULL, atio, 1);
#endif
} else {
PRINT_INFO("qla2x00tgt(%ld): Unable to "
"send the command to SCSI target "
"mid-level, sending BUSY status",
ha->instance);
if (!ha->tgt->tgt_shutdown) {
PRINT_INFO("qla2x00tgt(%ld): Unable to "
"send the command to SCSI target "
"mid-level, sending BUSY status",
ha->instance);
}
q2t_send_busy(ha, atio);
}
}
} else {
} else if (!ha->tgt->tgt_shutdown) {
PRINT_ERROR("qla2x00tgt(%ld): ATIO, but target mode "
"disabled", ha->instance);
}
@@ -1786,7 +1813,7 @@ static void q2t_response_pkt(scsi_qla_host_t *ha, sts_entry_t *pkt)
q2t_do_ctio_completion(ha, entry->handle,
le16_to_cpu(entry->status),
entry);
} else {
} else if (!ha->tgt->tgt_shutdown) {
PRINT_ERROR("qla2x00tgt(%ld): CTIO, but target mode "
"disabled", ha->instance);
}
@@ -1799,7 +1826,7 @@ static void q2t_response_pkt(scsi_qla_host_t *ha, sts_entry_t *pkt)
q2t_do_ctio_completion(ha, entry->handle,
le16_to_cpu(entry->status),
entry);
} else {
} else if (!ha->tgt->tgt_shutdown) {
PRINT_ERROR("qla2x00tgt(%ld): CTIO_A64, but target "
"mode disabled", ha->instance);
}
@@ -1853,8 +1880,6 @@ static void q2t_response_pkt(scsi_qla_host_t *ha, sts_entry_t *pkt)
entry->status);
}
tgt->disable_lun_status = entry->status;
wake_up_all(&tgt->waitQ);
} else {
PRINT_ERROR("qla2x00tgt(%ld): Unexpected MODIFY_LUN "
"received", (ha != NULL) ?ha->instance :-1);
@@ -1874,8 +1899,8 @@ static void q2t_response_pkt(scsi_qla_host_t *ha, sts_entry_t *pkt)
entry->status);
entry->status = ENABLE_LUN_SUCCESS;
} else if (entry->status == ENABLE_LUN_RC_NONZERO) {
TRACE_DBG("ENABLE_LUN succeeded but with error: "
"%#x", entry->status);
TRACE_DBG("ENABLE_LUN succeeded, but with "
"error: %#x", entry->status);
entry->status = ENABLE_LUN_SUCCESS;
} else if (entry->status != ENABLE_LUN_SUCCESS) {
PRINT_ERROR("qla2x00tgt(%ld): ENABLE_LUN "
@@ -1885,7 +1910,6 @@ static void q2t_response_pkt(scsi_qla_host_t *ha, sts_entry_t *pkt)
~ha->flags.enable_target_mode;
} /* else success */
tgt->disable_lun_status = entry->status;
wake_up_all(&tgt->waitQ);
}
break;
@@ -1910,7 +1934,7 @@ static void q2t_async_event(uint16_t code, scsi_qla_host_t *ha, uint16_t *mailbo
if (ha->tgt == NULL) {
TRACE(TRACE_DEBUG|TRACE_MGMT,
"ASYNC EVENT %#x but no tgt. ha %p tgt_flag %d",
"ASYNC EVENT %#x, but no tgt. ha %p tgt_flag %d",
code, ha, ha->flags.enable_target_mode);
goto out;
}
@@ -2007,7 +2031,6 @@ static void q2t_host_action(scsi_qla_host_t *ha,
tgt->ha = ha;
tgt->disable_lun_status = Q2T_DISABLE_LUN_STATUS_NOT_SET;
INIT_LIST_HEAD(&tgt->sess_list);
atomic_set(&tgt->sess_count, 0);
init_waitqueue_head(&tgt->waitQ);
if (ha->flags.enable_64bit_addressing) {
qla2x00t/qla2x00-target/qla2x00t.h
+2 -1
View File
@@ -133,7 +133,8 @@ struct q2t_tgt
int notify_ack_expected;
volatile int modify_lun_expected;
volatile int disable_lun_status;
atomic_t sess_count; /* count sessions refing q2t_tgt */
/* Count of sessions refering q2t_tgt, protected by hardware_lock */
int sess_count;
struct list_head sess_list;
};