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authorMuhammad Hamza Farooq <mfarooq@visteon.com>2015-09-11 17:42:38 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-09-21 08:52:13 +0300
commitb05b7c7cc0324524dcda7fa7c2be1255290ee416 (patch)
treeecaff7f9aebc82187b5613789b43c9c76d530420 /drivers/misc/ti-st
parentf97ef759999485df485fe19a440d6af02d561140 (diff)
downloadlinux-b05b7c7cc0324524dcda7fa7c2be1255290ee416.tar.xz
ti-st: use worker instead of calling st_int_write in wake up
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>
Diffstat (limited to 'drivers/misc/ti-st')
-rw-r--r--drivers/misc/ti-st/st_core.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/drivers/misc/ti-st/st_core.c b/drivers/misc/ti-st/st_core.c
index c8c6a363069c..6e3af8b42cdd 100644
--- a/drivers/misc/ti-st/st_core.c
+++ b/drivers/misc/ti-st/st_core.c
@@ -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;
}