[SCSI] st: Use mutex instead of semaphore

The SCSI Tape driver uses a semaphore as mutex. Use the mutex API
instead of the (binary) semaphore.

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Acked-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

2 files changed, 10 insertions, 9 deletions

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index a4f7b8465773..73c44cbdea47 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -1485,7 +1485,7 @@ st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
         struct st_buffer *STbp;
         char *name = tape_name(STp);
 
-        if (down_interruptible(&STp->lock))
+        if (mutex_lock_interruptible(&STp->lock))
                 return -ERESTARTSYS;
 
         retval = rw_checks(STp, filp, count);
@@ -1736,7 +1736,7 @@ st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
         if (SRpnt != NULL)
                 st_release_request(SRpnt);
         release_buffering(STp, 0);
-        up(&STp->lock);
+        mutex_unlock(&STp->lock);
 
         return retval;
 }
@@ -1942,7 +1942,7 @@ st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
         struct st_buffer *STbp = STp->buffer;
         DEB( char *name = tape_name(STp); )
 
-        if (down_interruptible(&STp->lock))
+        if (mutex_lock_interruptible(&STp->lock))
                 return -ERESTARTSYS;
 
         retval = rw_checks(STp, filp, count);
@@ -2069,7 +2069,7 @@ st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
                 release_buffering(STp, 1);
                 STbp->buffer_bytes = 0;
         }
-        up(&STp->lock);
+        mutex_unlock(&STp->lock);
 
         return retval;
 }
@@ -3226,7 +3226,7 @@ static int st_ioctl(struct inode *inode, struct file *file,
         char *name = tape_name(STp);
         void __user *p = (void __user *)arg;
 
-        if (down_interruptible(&STp->lock))
+        if (mutex_lock_interruptible(&STp->lock))
                 return -ERESTARTSYS;
 
         DEB(
@@ -3537,7 +3537,7 @@ static int st_ioctl(struct inode *inode, struct file *file,
                         retval = (-EFAULT);
                 goto out;
         }
-        up(&STp->lock);
+        mutex_unlock(&STp->lock);
         switch (cmd_in) {
                 case SCSI_IOCTL_GET_IDLUN:
                 case SCSI_IOCTL_GET_BUS_NUMBER:
@@ -3563,7 +3563,7 @@ static int st_ioctl(struct inode *inode, struct file *file,
         return retval;
 
  out:
-        up(&STp->lock);
+        mutex_unlock(&STp->lock);
         return retval;
 }
 
@@ -4029,7 +4029,7 @@ static int st_probe(struct device *dev)
 
         tpnt->density_changed = tpnt->compression_changed =
             tpnt->blksize_changed = 0;
-        init_MUTEX(&tpnt->lock);
+        mutex_init(&tpnt->lock);
 
         st_nr_dev++;
         write_unlock(&st_dev_arr_lock);
diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h
index 50f3deb1f9ed..6c8075712974 100644
--- a/drivers/scsi/st.h
+++ b/drivers/scsi/st.h
@@ -3,6 +3,7 @@
 #define _ST_H
 
 #include <linux/completion.h>
+#include <linux/mutex.h>
 #include <linux/kref.h>
 #include <scsi/scsi_cmnd.h>
 
@@ -98,7 +99,7 @@ struct st_partstat {
 struct scsi_tape {
         struct scsi_driver *driver;
         struct scsi_device *device;
-        struct semaphore lock;  /* For serialization */
+        struct mutex lock;      /* For serialization */
         struct completion wait; /* For SCSI commands */
         struct st_buffer *buffer;