[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>

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index ceca095..98156a9 100644 (file)
--- 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;
 
 }