On Mon, 8 Dec 2008, Andreas Bombe wrote:
Apart from sleep_on() calls that could be easily converted to
wait_event() and completion calls amiflop also used a flag in ms_delay()
and ms_isr() as a custom mutex for ms_delay() without a need for
explicit unlocking. I converted that to a standard mutex semaphore.
The replacement for the unconditional sleep_on() in fd_motor_on() is a
complete_all() together with a INIT_COMPLETION() before the mod_timer()
call. It appears to me that fd_motor_on() might be called concurrently
and fd_select() does not guarantee mutual exclusivity in the case the
same drive gets selected again.
Signed-off-by: Andreas Bombe <aeb@xxxxxxxxxx>
---
Note: I haven't tested these changes beyond correct compilation.
The complete_all() with INIT_COMPLETION() was because I'm not sure about
whether fd_motor_on() might run concurrently. Better safe than sorry.
I'm afraid my Amiga floppy drive doesn't work anymore...
Any other testers available?
--- a/drivers/block/amiflop.c
+++ b/drivers/block/amiflop.c
@@ -220,19 +218,17 @@ static irqreturn_t ms_isr(int irq, void *dummy)
A more generic routine would do a schedule a la timer.device */
static void ms_delay(int ms)
{
- unsigned long flags;
int ticks;
+ static DECLARE_MUTEX(mutex);
^^^^^^^^^^^^^
Shouldn't this be a real mutex (declared using DEFINE_MUTEX(mutex)) instead of
a semaphore used as a mutex?
+
if (ms > 0) {
- local_irq_save(flags);
- while (ms_busy == 0)
- sleep_on(&ms_wait);
- ms_busy = 0;
- local_irq_restore(flags);
+ down(&mutex);
^^^^
mutex_lock
ticks = MS_TICKS*ms-1;
ciaa.tblo=ticks%256;
ciaa.tbhi=ticks/256;
ciaa.crb=0x19; /*count eclock, force load, one-shoot, start */
- sleep_on(&ms_wait);
+ wait_for_completion(&ms_wait_completion);
+ up(&mutex);
mutex_unlock
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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