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ti-st: use worker instead of calling st_int_write in wake up

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The wake up method is called with the port lock held. The st_int_write
method calls port->ops->write with tries to acquire the lock again,
causing CPU to wait infinitely. Right way to do is to write data to port
in worker thread.

Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com>
Signed-off-by: Jacob Siverskog <jacob@teenage.engineering>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Muhammad Hamza Farooq 2015-09-11 16:42:38 +02:00 committed by Greg Kroah-Hartman
parent f97ef75999
commit b05b7c7cc0
2 changed files with 17 additions and 2 deletions
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18
drivers/misc/ti-st/st_core.c
View file

@ -460,6 +460,13 @@ static void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
* - TTY layer when write's finished
* - st_write (in context of the protocol stack)
*/
static void work_fn_write_wakeup(struct work_struct *work)
{
struct st_data_s *st_gdata = container_of(work, struct st_data_s,
work_write_wakeup);
st_tx_wakeup((void *)st_gdata);
}
void st_tx_wakeup(struct st_data_s *st_data)
{
struct sk_buff *skb;
@ -812,8 +819,12 @@ static void st_tty_wakeup(struct tty_struct *tty)
/* don't do an wakeup for now */
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
/* call our internal wakeup */
st_tx_wakeup((void *)st_gdata);
/*
* schedule the internal wakeup instead of calling directly to
* avoid lockup (port->lock needed in tty->ops->write is
* already taken here
*/
schedule_work(&st_gdata->work_write_wakeup);
}
static void st_tty_flush_buffer(struct tty_struct *tty)
@ -881,6 +892,9 @@ int st_core_init(struct st_data_s **core_data)
pr_err("unable to un-register ldisc");
return err;
}
INIT_WORK(&st_gdata->work_write_wakeup, work_fn_write_wakeup);
*core_data = st_gdata;
return 0;
}

1
include/linux/ti_wilink_st.h
View file

@ -158,6 +158,7 @@ struct st_data_s {
unsigned long ll_state;
void *kim_data;
struct tty_struct *tty;
struct work_struct work_write_wakeup;
};
/*