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| author | Muhammad Hamza Farooq <mfarooq@visteon.com> | 2015-09-11 16:42:38 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-09-20 22:52:13 -0700 |
| commit | b05b7c7cc0324524dcda7fa7c2be1255290ee416 (patch) | |
| tree | ecaff7f9aebc82187b5613789b43c9c76d530420 | |
| parent | f97ef759999485df485fe19a440d6af02d561140 (diff) | |
| download | linux-b05b7c7cc0324524dcda7fa7c2be1255290ee416.tar.gz linux-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>
| -rw-r--r-- | drivers/misc/ti-st/st_core.c | 18 | ||||
| -rw-r--r-- | include/linux/ti_wilink_st.h | 1 |
2 files changed, 17 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; } diff --git a/include/linux/ti_wilink_st.h b/include/linux/ti_wilink_st.h index d4217eff489f..0a0d56834c8e 100644 --- a/include/linux/ti_wilink_st.h +++ b/include/linux/ti_wilink_st.h @@ -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; }; /* |