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>

diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c
index b1c9bd9c1bfde04fb3b73a049c45e9eff4ed4d51..b42c9c479d4ba039367b6006383fa340dfd404e9 100644 (file)
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -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:

diff --git a/drivers/scsi/3w-9xxx.h b/drivers/scsi/3w-9xxx.h
index b6c208cc474f0e4ae5d37b0c7465c99129121cc7..d88cd3499bd52a68d2753d0ddf63c9e99d35d021 100644 (file)
--- a/drivers/scsi/3w-9xxx.h
+++ b/drivers/scsi/3w-9xxx.h
@@ -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;