From: Hannes Reinecke <hare@xxxxxxxx>
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@xxxxxxxx>
Reviewed-by: Lee Duncan <lduncan@xxxxxxxx>
This patch is based on the "misc" branch of the SCSI tree
and the 5-patch series for st sent by Jeff Mahoney 8/18/2012
and Ack-ed by Kai on 8/20.
Changes in v2: patch meta-data corrected
---
drivers/scsi/st.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index ceca095..98156a9 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;
}
--
1.7.11.5
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