st: cdev lock_kernel() pushdown

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index e8db66ad0bde..e93544dd81bf 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -38,6 +38,7 @@ static const char *verstr = "20080224";
 #include <linux/cdev.h>
 #include <linux/delay.h>
 #include <linux/mutex.h>
+#include <linux/smp_lock.h>
 
 #include <asm/uaccess.h>
 #include <asm/dma.h>
@@ -1113,7 +1114,7 @@ static int check_tape(struct scsi_tape *STp, struct file *filp)
 }
 
 
-/* Open the device. Needs to be called with BKL only because of incrementing the SCSI host
+/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
    module count. */
 static int st_open(struct inode *inode, struct file *filp)
 {
@@ -1123,6 +1124,7 @@ static int st_open(struct inode *inode, struct file *filp)
         int dev = TAPE_NR(inode);
         char *name;
 
+        lock_kernel();
         /*
          * 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
@@ -1130,8 +1132,10 @@ static int st_open(struct inode *inode, struct file *filp)
          */
         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
 
-        if (!(STp = scsi_tape_get(dev)))
+        if (!(STp = scsi_tape_get(dev))) {
+                unlock_kernel();
                 return -ENXIO;
+        }
 
         write_lock(&st_dev_arr_lock);
         filp->private_data = STp;
@@ -1140,6 +1144,7 @@ static int st_open(struct inode *inode, struct file *filp)
         if (STp->in_use) {
                 write_unlock(&st_dev_arr_lock);
                 scsi_tape_put(STp);
+                unlock_kernel();
                 DEB( printk(ST_DEB_MSG "%s: Device already in use.\n", name); )
                 return (-EBUSY);
         }
@@ -1188,12 +1193,14 @@ static int st_open(struct inode *inode, struct file *filp)
                         retval = (-EIO);
                 goto err_out;
         }
+        unlock_kernel();
         return 0;
 
  err_out:
         normalize_buffer(STp->buffer);
         STp->in_use = 0;
         scsi_tape_put(STp);
+        unlock_kernel();
         return retval;
 
 }