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Message-ID: <20081210010219.GB5073@infernal.debian.net>
Date: Wed, 10 Dec 2008 02:02:19 +0100
From: Andreas Bombe <aeb@...ian.org>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: linux-m68k@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] amiflop: get rid of sleep_on calls
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.
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@...ian.org>
---
This version changes the struct semaphore used as mutex into a struct
mutex. Still only compile tested.
I just tried out my Amiga and it appears to be in better shape than
expected. So I might get to actually test it when I find the time. My
Amiga has no Linux installation so I need to whip up a ramdisk or
something else sufficient to test it.
drivers/block/amiflop.c | 40 ++++++++++++++++------------------------
1 files changed, 16 insertions(+), 24 deletions(-)
diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c
index 4b1d4ac..8df436f 100644
--- a/drivers/block/amiflop.c
+++ b/drivers/block/amiflop.c
@@ -156,7 +156,7 @@ static volatile int fdc_busy = -1;
static volatile int fdc_nested;
static DECLARE_WAIT_QUEUE_HEAD(fdc_wait);
-static DECLARE_WAIT_QUEUE_HEAD(motor_wait);
+static DECLARE_COMPLETION(motor_on_completion);
static volatile int selected = -1; /* currently selected drive */
@@ -184,8 +184,7 @@ static unsigned char mfmencode[16]={
static unsigned char mfmdecode[128];
/* floppy internal millisecond timer stuff */
-static volatile int ms_busy = -1;
-static DECLARE_WAIT_QUEUE_HEAD(ms_wait);
+static DECLARE_COMPLETION(ms_wait_completion);
#define MS_TICKS ((amiga_eclock+50)/1000)
/*
@@ -211,8 +210,7 @@ static int fd_device[4] = { 0, 0, 0, 0 };
static irqreturn_t ms_isr(int irq, void *dummy)
{
- ms_busy = -1;
- wake_up(&ms_wait);
+ complete(&ms_wait_completion);
return IRQ_HANDLED;
}
@@ -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 DEFINE_MUTEX(mutex);
+
if (ms > 0) {
- local_irq_save(flags);
- while (ms_busy == 0)
- sleep_on(&ms_wait);
- ms_busy = 0;
- local_irq_restore(flags);
+ mutex_lock(&mutex);
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);
+ mutex_unlock(&mutex);
}
}
@@ -254,8 +250,7 @@ static void get_fdc(int drive)
printk("get_fdc: drive %d fdc_busy %d fdc_nested %d\n",drive,fdc_busy,fdc_nested);
#endif
local_irq_save(flags);
- while (!try_fdc(drive))
- sleep_on(&fdc_wait);
+ wait_event(fdc_wait, try_fdc(drive));
fdc_busy = drive;
fdc_nested++;
local_irq_restore(flags);
@@ -330,7 +325,7 @@ static void fd_deselect (int drive)
static void motor_on_callback(unsigned long nr)
{
if (!(ciaa.pra & DSKRDY) || --on_attempts == 0) {
- wake_up (&motor_wait);
+ complete_all(&motor_on_completion);
} else {
motor_on_timer.expires = jiffies + HZ/10;
add_timer(&motor_on_timer);
@@ -347,11 +342,12 @@ static int fd_motor_on(int nr)
unit[nr].motor = 1;
fd_select(nr);
+ INIT_COMPLETION(motor_on_completion);
motor_on_timer.data = nr;
mod_timer(&motor_on_timer, jiffies + HZ/2);
on_attempts = 10;
- sleep_on (&motor_wait);
+ wait_for_completion(&motor_on_completion);
fd_deselect(nr);
}
@@ -582,8 +578,7 @@ static void raw_read(int drive)
{
drive&=3;
get_fdc(drive);
- while (block_flag)
- sleep_on(&wait_fd_block);
+ wait_event(wait_fd_block, !block_flag);
fd_select(drive);
/* setup adkcon bits correctly */
custom.adkcon = ADK_MSBSYNC;
@@ -598,8 +593,7 @@ static void raw_read(int drive)
block_flag = 1;
- while (block_flag)
- sleep_on (&wait_fd_block);
+ wait_event(wait_fd_block, !block_flag);
custom.dsklen = 0;
fd_deselect(drive);
@@ -616,8 +610,7 @@ static int raw_write(int drive)
rel_fdc();
return 0;
}
- while (block_flag)
- sleep_on(&wait_fd_block);
+ wait_event(wait_fd_block, !block_flag);
fd_select(drive);
/* clear adkcon bits */
custom.adkcon = ADK_PRECOMP1|ADK_PRECOMP0|ADK_WORDSYNC|ADK_MSBSYNC;
@@ -1294,8 +1287,7 @@ static int non_int_flush_track (unsigned long nr)
writepending = 0;
return 0;
}
- while (block_flag == 2)
- sleep_on (&wait_fd_block);
+ wait_event(wait_fd_block, block_flag != 2);
}
else {
local_irq_restore(flags);
--
1.5.6.5
--
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