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tcm_fc: Convert to wake_up_process and schedule_timeout_interruptible

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This patch converts ft_queue_cmd() to use wake_up_process() and
ft_thread() to use schedule_timeout_interruptible(MAX_SCHEDULE_TIMEOUT)
instead of wait_event_interruptible().  This fixes a potential race with
the wait_event_interruptible() conditional with qobj->queue_cnt in
ft_thread().

This patch also drops the unnecessary set_user_nice(current, -20) in
ft_thread(), and drops extra () around two if (!(acl)) conditionals in
tfc_conf.c.

Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger
2011-05-27 13:58:48 -07:00
parent a1fa375958
commit 2be18149d9
2 changed files with 10 additions and 11 deletions
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17
drivers/target/tcm_fc/tfc_cmd.c
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@@ -94,15 +94,17 @@ void ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
static void ft_queue_cmd(struct ft_sess *sess, struct ft_cmd *cmd)
{
struct se_queue_obj *qobj;
struct ft_tpg *tpg = sess->tport->tpg;
struct se_queue_obj *qobj = &tpg->qobj;
unsigned long flags;
qobj = &sess->tport->tpg->qobj;
spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
list_add_tail(&cmd->se_req.qr_list, &qobj->qobj_list);
spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
atomic_inc(&qobj->queue_cnt);
wake_up_interruptible(&qobj->thread_wq);
spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
wake_up_process(tpg->thread);
}
static struct ft_cmd *ft_dequeue_cmd(struct se_queue_obj *qobj)
@@ -688,15 +690,12 @@ int ft_thread(void *arg)
struct ft_tpg *tpg = arg;
struct se_queue_obj *qobj = &tpg->qobj;
struct ft_cmd *cmd;
int ret;
set_user_nice(current, -20);
while (!kthread_should_stop()) {
ret = wait_event_interruptible(qobj->thread_wq,
atomic_read(&qobj->queue_cnt) || kthread_should_stop());
if (ret < 0 || kthread_should_stop())
schedule_timeout_interruptible(MAX_SCHEDULE_TIMEOUT);
if (kthread_should_stop())
goto out;
cmd = ft_dequeue_cmd(qobj);
if (cmd)
ft_exec_req(cmd);