lkml.org 
[lkml]   [2012]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH] tty: the briq panel isn't a tty, make it use its own locking
From
Date
On Thu, 2012-02-23 at 13:39 +0000, Alan Cox wrote:
> From: Alan Cox <alan@linux.intel.com>
>
> The driver appears to be terminall broken, if nobody is maintaining it then
> perhaps it should go into staging and the out-tray.

Hrm, I don't think anybody maintains it but I do have a BriQ somewhere
in storage, so I suppose I could pick it up, not that I need another
crap driver to deal with right now though...

Cheers,
Ben.

> (Fixed bug noted by Jiri)
>
> Signed-off-by: Alan Cox <alan@linux.intel.com>
> ---
>
> drivers/char/briq_panel.c | 26 +++++++-------------------
> 1 files changed, 7 insertions(+), 19 deletions(-)
>
>
> diff --git a/drivers/char/briq_panel.c b/drivers/char/briq_panel.c
> index 095ab90..3335d07 100644
> --- a/drivers/char/briq_panel.c
> +++ b/drivers/char/briq_panel.c
> @@ -20,6 +20,7 @@
> #include <linux/mm.h>
> #include <linux/init.h>
>
> +#include <asm/bitops.h>
> #include <asm/uaccess.h>
> #include <asm/io.h>
> #include <asm/prom.h>
> @@ -30,7 +31,7 @@
> #define BRIQ_PANEL_VER "1.1 (04/20/2002)"
> #define BRIQ_PANEL_MSG0 "Loading Linux"
>
> -static int vfd_is_open;
> +static unsigned long vfd_is_open;
> static unsigned char vfd[40];
> static int vfd_cursor;
> static unsigned char ledpb, led;
> @@ -66,37 +67,27 @@ static void set_led(char state)
>
> static int briq_panel_open(struct inode *ino, struct file *filep)
> {
> - tty_lock();
> - /* enforce single access, vfd_is_open is protected by BKL */
> - if (vfd_is_open) {
> - tty_unlock();
> + /* enforce single open */
> + if (test_and_set_bit(0, &vfd_is_open))
> return -EBUSY;
> }
> - vfd_is_open = 1;
> -
> - tty_unlock();
> return 0;
> }
>
> static int briq_panel_release(struct inode *ino, struct file *filep)
> {
> - if (!vfd_is_open)
> - return -ENODEV;
> -
> - vfd_is_open = 0;
> -
> + clear_bit(0, &vfd_is_open);
> return 0;
> }
>
> +/* Note that single open doesn't mean single threaded read or write so all
> + this code is unsafe */
> static ssize_t briq_panel_read(struct file *file, char __user *buf, size_t count,
> loff_t *ppos)
> {
> unsigned short c;
> unsigned char cp;
>
> - if (!vfd_is_open)
> - return -ENODEV;
> -
> c = (inb(BRIQ_PANEL_LED_IOPORT) & 0x000c) | (ledpb & 0x0003);
> set_led(' ');
> /* upper button released */
> @@ -137,9 +128,6 @@ static ssize_t briq_panel_write(struct file *file, const char __user *buf, size_
> size_t indx = len;
> int i, esc = 0;
>
> - if (!vfd_is_open)
> - return -EBUSY;
> -
> for (;;) {
> char c;
> if (!indx)




\
 
 \ /
  Last update: 2012-02-23 21:45    [W:0.055 / U:39.468 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site