Commit 07ffd4ce authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Martin K. Petersen
Browse files

scsi: 3w-9xxx: rework lock timeouts 



The TW_IOCTL_GET_LOCK ioctl uses do_gettimeofday() to check whether a
lock has expired. This can misbehave due to a concurrent settimeofday()
call, as it is based on 'real' time, and it will overflow in y2038 on
32-bit architectures, producing unexpected results when used across the
overflow time.

This changes it to using monotonic time, using ktime_get() to simplify
the code.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarAdam Radford <aradford@gmail.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent bc8f9166

drivers/scsi/3w-9xxx.c

+6 −7
Original line number Diff line number Diff line
@@ -645,8 +645,7 @@ static long twa_chrdev_ioctl(struct file *file, unsigned int cmd, unsigned long 
	TW_Command_Full *full_command_packet;

	TW_Compatibility_Info *tw_compat_info;

	TW_Event *event;

	struct timeval current_time;

	u32 current_time_ms;

	ktime_t current_time;

	TW_Device_Extension *tw_dev = twa_device_extension_list[iminor(inode)];

	int retval = TW_IOCTL_ERROR_OS_EFAULT;

	void __user *argp = (void __user *)arg;
@@ -837,17 +836,17 @@ static long twa_chrdev_ioctl(struct file *file, unsigned int cmd, unsigned long 
		break;

	case TW_IOCTL_GET_LOCK:

		tw_lock = (TW_Lock *)tw_ioctl->data_buffer;

		do_gettimeofday(&current_time);

		current_time_ms = (current_time.tv_sec * 1000) + (current_time.tv_usec / 1000);

		current_time = ktime_get();



		if ((tw_lock->force_flag == 1) || (tw_dev->ioctl_sem_lock == 0) || (current_time_ms >= tw_dev->ioctl_msec)) {

		if ((tw_lock->force_flag == 1) || (tw_dev->ioctl_sem_lock == 0) ||

		    ktime_after(current_time, tw_dev->ioctl_time)) {

			tw_dev->ioctl_sem_lock = 1;

			tw_dev->ioctl_msec = current_time_ms + tw_lock->timeout_msec;

			tw_dev->ioctl_time = ktime_add_ms(current_time, tw_lock->timeout_msec);

			tw_ioctl->driver_command.status = 0;

			tw_lock->time_remaining_msec = tw_lock->timeout_msec;

		} else {

			tw_ioctl->driver_command.status = TW_IOCTL_ERROR_STATUS_LOCKED;

			tw_lock->time_remaining_msec = tw_dev->ioctl_msec - current_time_ms;

			tw_lock->time_remaining_msec = ktime_ms_delta(tw_dev->ioctl_time, current_time);

		}

		break;

	case TW_IOCTL_RELEASE_LOCK:

drivers/scsi/3w-9xxx.h

+1 −1
Original line number Diff line number Diff line
@@ -666,7 +666,7 @@ typedef struct TAG_TW_Device_Extension { 
	unsigned char		event_queue_wrapped;

	unsigned int            error_sequence_id;

	int                     ioctl_sem_lock;

	u32                     ioctl_msec;

	ktime_t                 ioctl_time;

	int			chrdev_request_id;

	wait_queue_head_t	ioctl_wqueue;

	struct mutex		ioctl_lock;

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