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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: Arnd Bergmann <arnd@arndb.de>
Acked-by: Adam Radford <aradford@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Arnd Bergmann 2017-11-10 16:58:27 +01:00 committed by Martin K. Petersen
parent bc8f91665b
commit 07ffd4ce80
2 changed files with 7 additions and 8 deletions
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13
drivers/scsi/3w-9xxx.c
View File

@ -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:

2
drivers/scsi/3w-9xxx.h
View File

@ -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;