linux-kernel - [PATCH] block/floppy: Convert callback to pass timer

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Date:   Wed, 4 Oct 2017 17:49:29 -0700
From:   Kees Cook <keescook@...omium.org>
To:     linux-kernel@...r.kernel.org
Cc:     Jiri Kosina <jikos@...nel.org>, Jens Axboe <axboe@...nel.dk>,
        Ming Lei <tom.leiming@...il.com>,
        Al Viro <viro@...iv.linux.org.uk>,
        Geliang Tang <geliangtang@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH] block/floppy: Convert callback to pass timer_list

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to passing in the timer pointer explicitly.
Calculate the drive from the offset of the timer in the timer list.

Cc: Jiri Kosina <jikos@...nel.org>
Cc: Jens Axboe <axboe@...nel.dk>
Cc: Ming Lei <tom.leiming@...il.com>
Cc: Al Viro <viro@...iv.linux.org.uk>
Cc: Geliang Tang <geliangtang@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Kees Cook <keescook@...omium.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/floppy.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 60c086a53609..9390bd078fb0 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -899,10 +899,14 @@ static void unlock_fdc(void)
 }
 
 /* switches the motor off after a given timeout */
-static void motor_off_callback(unsigned long nr)
+static void motor_off_callback(struct timer_list *t)
 {
+	unsigned long nr = t - motor_off_timer;
 	unsigned char mask = ~(0x10 << UNIT(nr));
 
+	if (WARN_ON_ONCE(nr >= N_DRIVE))
+		return;
+
 	set_dor(FDC(nr), mask, 0);
 }
 
@@ -3043,7 +3047,7 @@ static void raw_cmd_done(int flag)
 		else
 			raw_cmd->flags &= ~FD_RAW_DISK_CHANGE;
 		if (raw_cmd->flags & FD_RAW_NO_MOTOR_AFTER)
-			motor_off_callback(current_drive);
+			motor_off_callback(&motor_off_timer[current_drive]);
 
 		if (raw_cmd->next &&
 		    (!(raw_cmd->flags & FD_RAW_FAILURE) ||
@@ -4538,7 +4542,7 @@ static int __init do_floppy_init(void)
 		disks[drive]->fops = &floppy_fops;
 		sprintf(disks[drive]->disk_name, "fd%d", drive);
 
-		setup_timer(&motor_off_timer[drive], motor_off_callback, drive);
+		timer_setup(&motor_off_timer[drive], motor_off_callback, 0);
 	}
 
 	err = register_blkdev(FLOPPY_MAJOR, "fd");
-- 
2.7.4


-- 
Kees Cook
Pixel Security