[PATCH] amifloppy: Convert timers to use timer_setup()

[PATCH] amifloppy: Convert timers to use timer_setup()

[Kees Cook]

This converts the amifloppy driver to pass the timer pointer to the
callback instead of the drive number (and flags). It eliminates the
decusagecounter flag, as it was unused, and drops the ininterrupt flag
which appeared to be a needless optimization. The drive can then be
calculated from the offset of the timer in the drive timer array.

Additionally moves to a static data variable instead of the
soon-to-be-gone timer->data field.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Krzysztof Halasa <khc@pm.waw.pl>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
This requires commit 686fef928bba ("timer: Prepare to change timer
callback argument type") in v4.14-rc3, but should be otherwise
stand-alone.
---
 drivers/block/amiflop.c | 58 ++++++++++++++++++++++---------------------------
 1 file changed, 26 insertions(+), 32 deletions(-)

diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c
index 49908c74bfcb..e5aa62fcf5a8 100644
--- a/drivers/block/amiflop.c
+++ b/drivers/block/amiflop.c
@@ -146,6 +146,7 @@ static struct amiga_floppy_struct unit[FD_MAX_UNITS];
 
 static struct timer_list flush_track_timer[FD_MAX_UNITS];
 static struct timer_list post_write_timer;
+static unsigned long post_write_timer_drive;
 static struct timer_list motor_on_timer;
 static struct timer_list motor_off_timer[FD_MAX_UNITS];
 static int on_attempts;
@@ -323,7 +324,7 @@ static void fd_deselect (int drive)
 
 }
 
-static void motor_on_callback(unsigned long nr)
+static void motor_on_callback(struct timer_list *unused)
 {
 	if (!(ciaa.pra & DSKRDY) || --on_attempts == 0) {
 		complete_all(&motor_on_completion);
@@ -344,7 +345,6 @@ static int fd_motor_on(int nr)
 		fd_select(nr);
 
 		reinit_completion(&motor_on_completion);
-		motor_on_timer.data = nr;
 		mod_timer(&motor_on_timer, jiffies + HZ/2);
 
 		on_attempts = 10;
@@ -356,7 +356,7 @@ static int fd_motor_on(int nr)
 		on_attempts = -1;
 #if 0
 		printk (KERN_ERR "motor_on failed, turning motor off\n");
-		fd_motor_off (nr);
+		fd_motor_off (motor_off_timer + nr);
 		return 0;
 #else
 		printk (KERN_WARNING "DSKRDY not set after 1.5 seconds - assuming drive is spinning notwithstanding\n");
@@ -366,20 +366,17 @@ static int fd_motor_on(int nr)
 	return 1;
 }
 
-static void fd_motor_off(unsigned long drive)
+static void fd_motor_off(struct timer_list *timer)
 {
-	long calledfromint;
-#ifdef MODULE
-	long decusecount;
+	unsigned long drive = ((unsigned long)timer -
+			       (unsigned long)&motor_off_timer[0]) /
+					sizeof(motor_off_timer[0]);
 
-	decusecount = drive & 0x40000000;
-#endif
-	calledfromint = drive & 0x80000000;
 	drive&=3;
-	if (calledfromint && !try_fdc(drive)) {
+	if (!try_fdc(drive)) {
 		/* We would be blocked in an interrupt, so try again later */
-		motor_off_timer[drive].expires = jiffies + 1;
-		add_timer(motor_off_timer + drive);
+		timer->expires = jiffies + 1;
+		add_timer(timer);
 		return;
 	}
 	unit[drive].motor = 0;
@@ -393,8 +390,6 @@ static void floppy_off (unsigned int nr)
 	int drive;
 
 	drive = nr & 3;
-	/* called this way it is always from interrupt */
-	motor_off_timer[drive].data = nr | 0x80000000;
 	mod_timer(motor_off_timer + drive, jiffies + 3*HZ);
 }
 
@@ -436,7 +431,7 @@ static int fd_calibrate(int drive)
 			break;
 		if (--n == 0) {
 			printk (KERN_ERR "fd%d: calibrate failed, turning motor off\n", drive);
-			fd_motor_off (drive);
+			fd_motor_off (motor_off_timer + drive);
 			unit[drive].track = -1;
 			rel_fdc();
 			return 0;
@@ -565,7 +560,7 @@ static irqreturn_t fd_block_done(int irq, void *dummy)
 	if (block_flag == 2) { /* writing */
 		writepending = 2;
 		post_write_timer.expires = jiffies + 1; /* at least 2 ms */
-		post_write_timer.data = selected;
+		post_write_timer_drive = selected;
 		add_timer(&post_write_timer);
 	}
 	else {                /* reading */
@@ -652,6 +647,10 @@ static void post_write (unsigned long drive)
 	rel_fdc(); /* corresponds to get_fdc() in raw_write */
 }
 
+static void post_write_callback(struct timer_list *timer)
+{
+	post_write(post_write_timer_drive);
+}
 
 /*
  * The following functions are to convert the block contents into raw data
@@ -1245,8 +1244,12 @@ static void dos_write(int disk)
 /* FIXME: this assumes the drive is still spinning -
  * which is only true if we complete writing a track within three seconds
  */
-static void flush_track_callback(unsigned long nr)
+static void flush_track_callback(struct timer_list *timer)
 {
+	unsigned long nr = ((unsigned long)timer -
+			       (unsigned long)&flush_track_timer[0]) /
+					sizeof(flush_track_timer[0]);
+
 	nr&=3;
 	writefromint = 1;
 	if (!try_fdc(nr)) {
@@ -1650,8 +1653,7 @@ static void floppy_release(struct gendisk *disk, fmode_t mode)
 		fd_ref[drive] = 0;
 	}
 #ifdef MODULE
-/* the mod_use counter is handled this way */
-	floppy_off (drive | 0x40000000);
+	floppy_off (drive);
 #endif
 	mutex_unlock(&amiflop_mutex);
 }
@@ -1792,27 +1794,19 @@ static int __init amiga_floppy_probe(struct platform_device *pdev)
 				floppy_find, NULL, NULL);
 
 	/* initialize variables */
-	init_timer(&motor_on_timer);
+	timer_setup(&motor_on_timer, motor_on_callback, 0);
 	motor_on_timer.expires = 0;
-	motor_on_timer.data = 0;
-	motor_on_timer.function = motor_on_callback;
 	for (i = 0; i < FD_MAX_UNITS; i++) {
-		init_timer(&motor_off_timer[i]);
+		timer_setup(&motor_off_timer[i], fd_motor_off, 0);
 		motor_off_timer[i].expires = 0;
-		motor_off_timer[i].data = i|0x80000000;
-		motor_off_timer[i].function = fd_motor_off;
-		init_timer(&flush_track_timer[i]);
+		timer_setup(&flush_track_timer[i], flush_track_callback, 0);
 		flush_track_timer[i].expires = 0;
-		flush_track_timer[i].data = i;
-		flush_track_timer[i].function = flush_track_callback;
 
 		unit[i].track = -1;
 	}
 
-	init_timer(&post_write_timer);
+	timer_setup(&post_write_timer, post_write_callback, 0);
 	post_write_timer.expires = 0;
-	post_write_timer.data = 0;
-	post_write_timer.function = post_write;
   
 	for (i = 0; i < 128; i++)
 		mfmdecode[i]=255;
-- 
2.7.4


-- 
Kees Cook
Pixel Security

Re: [PATCH] amifloppy: Convert timers to use timer_setup()

[Jens Axboe]

On 10/04/2017 06:48 PM, Kees Cook wrote:
> This converts the amifloppy driver to pass the timer pointer to the
> callback instead of the drive number (and flags). It eliminates the
> decusagecounter flag, as it was unused, and drops the ininterrupt flag
> which appeared to be a needless optimization. The drive can then be
> calculated from the offset of the timer in the drive timer array.

Applied for 4.15.

-- 
Jens Axboe