mirrors/scst
1
0
Fork 0
mirror of https://github.com/SCST-project/scst.git synced 2026-05-29 09:50:19 +00:00
Code Issues Packages Projects Releases Wiki Activity

Prevent reverse order of management commands

Browse Source 
git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@3887 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Vladislav Bolkhovitin
2011-10-05 02:11:19 +00:00
parent fdce259c4f
commit 3c54b0c18c
1 changed files with 46 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
scst/src/dev_handlers/scst_user.c
View File

@@ -1065,6 +1065,48 @@ static int dev_user_tape_done(struct scst_cmd *cmd)
return res;
}
static inline bool dev_user_mgmt_ucmd(struct scst_user_cmd *ucmd)
{
return (ucmd->state == UCMD_STATE_TM_EXECING) ||
(ucmd->state == UCMD_STATE_ATTACH_SESS) ||
(ucmd->state == UCMD_STATE_DETACH_SESS);
}
/* Supposed to be called under cmd_list_lock */
static inline void dev_user_add_to_ready_head(struct scst_user_cmd *ucmd)
{
struct scst_user_dev *dev = ucmd->dev;
struct list_head *entry;
TRACE_ENTRY();
__list_for_each(entry, &dev->ready_cmd_list) {
struct scst_user_cmd *u = list_entry(entry,
struct scst_user_cmd, ready_cmd_list_entry);
/*
* Skip other queued mgmt commands to not reverse order
* of them and prevent conditions, where DETACH_SESS or a SCSI
* command comes before ATTACH_SESS for the same session.
*/
if (unlikely(dev_user_mgmt_ucmd(u)))
continue;
TRACE_DBG("Adding ucmd %p (state %d) after mgmt ucmd %p (state "
"%d)", ucmd, ucmd->state, u, u->state);
list_add_tail(&ucmd->ready_cmd_list_entry,
&u->ready_cmd_list_entry);
goto out;
}
TRACE_DBG("Adding ucmd %p (state %d) to tail "
"of mgmt ready cmd list", ucmd, ucmd->state);
list_add_tail(&ucmd->ready_cmd_list_entry,
&dev->ready_cmd_list);
out:
TRACE_EXIT();
return;
}
static void dev_user_add_to_ready(struct scst_user_cmd *ucmd)
{
struct scst_user_dev *dev = ucmd->dev;
@@ -1091,25 +1133,16 @@ static void dev_user_add_to_ready(struct scst_user_cmd *ucmd)
* of our commands completed in NOP timeout to allow the head
* commands to go, then we are really overloaded and/or stuck.
*/
TRACE_DBG("Adding ucmd %p (state %d) to head of ready "
"cmd list", ucmd, ucmd->state);
list_add(&ucmd->ready_cmd_list_entry,
&dev->ready_cmd_list);
} else if (unlikely(ucmd->state == UCMD_STATE_TM_EXECING) ||
unlikely(ucmd->state == UCMD_STATE_ATTACH_SESS) ||
unlikely(ucmd->state == UCMD_STATE_DETACH_SESS)) {
TRACE_MGMT_DBG("Adding mgmt ucmd %p (state %d) to head of "
"ready cmd list", ucmd, ucmd->state);
list_add(&ucmd->ready_cmd_list_entry,
&dev->ready_cmd_list);
dev_user_add_to_ready_head(ucmd);
} else if (unlikely(dev_user_mgmt_ucmd(ucmd))) {
dev_user_add_to_ready_head(ucmd);
do_wake = 1;
} else {
if ((ucmd->cmd != NULL) &&
unlikely((ucmd->cmd->queue_type == SCST_CMD_QUEUE_HEAD_OF_QUEUE))) {
TRACE_DBG("Adding HQ ucmd %p to head of ready cmd list",
ucmd);
list_add(&ucmd->ready_cmd_list_entry,
&dev->ready_cmd_list);
dev_user_add_to_ready_head(ucmd);
} else {
TRACE_DBG("Adding ucmd %p to ready cmd list", ucmd);
list_add_tail(&ucmd->ready_cmd_list_entry,