[SCSI] st: remove st_mutex

The st_mutex was created when the BKL was removed, and
prevents simultaneous st_open calls. It is better to
protect just the necessary data.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Lee Duncan <lduncan@suse.com>
Acked-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 2 insertions, 6 deletions

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index ceca095e5d8d..98156a97c472 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -75,7 +75,6 @@ static const char *verstr = "20101219";
 #include "st_options.h"
 #include "st.h"
 
-static DEFINE_MUTEX(st_mutex);
 static int buffer_kbs;
 static int max_sg_segs;
 static int try_direct_io = TRY_DIRECT_IO;
@@ -1185,7 +1184,6 @@ static int st_open(struct inode *inode, struct file *filp)
         int dev = TAPE_NR(inode);
         char *name;
 
-        mutex_lock(&st_mutex);
         /*
          * We really want to do nonseekable_open(inode, filp); here, but some
          * versions of tar incorrectly call lseek on tapes and bail out if that
@@ -1194,7 +1192,6 @@ static int st_open(struct inode *inode, struct file *filp)
         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
 
         if (!(STp = scsi_tape_get(dev))) {
-                mutex_unlock(&st_mutex);
                 return -ENXIO;
         }
 
@@ -1205,7 +1202,6 @@ static int st_open(struct inode *inode, struct file *filp)
         if (STp->in_use) {
                 spin_unlock(&st_use_lock);
                 scsi_tape_put(STp);
-                mutex_unlock(&st_mutex);
                 DEB( printk(ST_DEB_MSG "%s: Device already in use.\n", name); )
                 return (-EBUSY);
         }
@@ -1259,16 +1255,16 @@ static int st_open(struct inode *inode, struct file *filp)
                         retval = (-EIO);
                 goto err_out;
         }
-        mutex_unlock(&st_mutex);
         return 0;
 
  err_out:
         normalize_buffer(STp->buffer);
+        spin_lock(&st_use_lock);
         STp->in_use = 0;
+        spin_unlock(&st_use_lock);
         scsi_tape_put(STp);
         if (resumed)
                 scsi_autopm_put_device(STp->device);
-        mutex_unlock(&st_mutex);
         return retval;
 
 }