renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-18 18:23:53 +08:00
Code

nozomi: Fix mutex handling

Browse Source 
The original author didn't realise the kernel lock was a drop while sleep
lock so did clever (and wrong) things to work around the non need to avoid
deadlocks. Remove the cleverness and the comment (as we don't hold the BKL
now anyway in those paths)

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Cox 2010-02-08 10:07:04 +00:00 committed by Greg Kroah-Hartman
parent 266794eb71
commit e8c65d143a
1 changed files with 12 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/char/nozomi.c
View File

@ -1693,15 +1693,7 @@ static int ntty_write(struct tty_struct *tty, const unsigned char *buffer,
if (!dc || !port)
return -ENODEV;
if (unlikely(!mutex_trylock(&port->tty_sem))) {
/*
* must test lock as tty layer wraps calls
* to this function with BKL
*/
dev_err(&dc->pdev->dev, "Would have deadlocked - "
"return EAGAIN\n");
return -EAGAIN;
}
mutex_lock(&port->tty_sem);
if (unlikely(!port->port.count)) {
DBG1(" ");
@ -1741,25 +1733,23 @@ exit:
* This method is called by the upper tty layer.
* #according to sources N_TTY.c it expects a value >= 0 and
* does not check for negative values.
*
* If the port is unplugged report lots of room and let the bits
* dribble away so we don't block anything.
*/
static int ntty_write_room(struct tty_struct *tty)
{
struct port *port = tty->driver_data;
int room = 0;
int room = 4096;
const struct nozomi *dc = get_dc_by_tty(tty);
if (!dc || !port)
return 0;
if (!mutex_trylock(&port->tty_sem))
return 0;
if (!port->port.count)
goto exit;
room = port->fifo_ul.size - kfifo_len(&port->fifo_ul);
exit:
mutex_unlock(&port->tty_sem);
if (dc) {
mutex_lock(&port->tty_sem);
if (port->port.count)
room = port->fifo_ul.size -
kfifo_len(&port->fifo_ul);
mutex_unlock(&port->tty_sem);
}
return room;
}