scsi: autoconvert trivial BKL users to private mutex
All these files use the big kernel lock in a trivial
way to serialize their private file operations,
typically resulting from an earlier semi-automatic
pushdown from VFS.
None of these drivers appears to want to lock against
other code, and they all use the BKL as the top-level
lock in their file operations, meaning that there
is no lock-order inversion problem.
Consequently, we can remove the BKL completely,
replacing it with a per-file mutex in every case.
Using a scripted approach means we can avoid
typos.
file=$1
name=$2
if grep -q lock_kernel ${file} ; then
if grep -q 'include.*linux.mutex.h' ${file} ; then
sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
else
sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
fi
sed -i ${file} \
-e "/^#include.*linux.mutex.h/,$ {
1,/^\(static\|int\|long\)/ {
/^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);
} }" \
-e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
-e '/[ ]*cycle_kernel_lock();/d'
else
sed -i -e '/include.*\<smp_lock.h\>/d' ${file} \
-e '/cycle_kernel_lock()/d'
fi
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: linux-scsi@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@suse.de>
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 78d6163..b5507d5 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -49,7 +49,7 @@
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/blktrace_api.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include "scsi.h"
#include <scsi/scsi_dbg.h>
@@ -103,6 +103,8 @@
static int sg_add(struct device *, struct class_interface *);
static void sg_remove(struct device *, struct class_interface *);
+static DEFINE_MUTEX(sg_mutex);
+
static DEFINE_IDR(sg_index_idr);
static DEFINE_RWLOCK(sg_index_lock); /* Also used to lock
file descriptor list for device */
@@ -229,7 +231,7 @@
int res;
int retval;
- lock_kernel();
+ mutex_lock(&sg_mutex);
nonseekable_open(inode, filp);
SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
sdp = sg_get_dev(dev);
@@ -314,7 +316,7 @@
sg_put:
if (sdp)
sg_put_dev(sdp);
- unlock_kernel();
+ mutex_unlock(&sg_mutex);
return retval;
}
@@ -1092,9 +1094,9 @@
{
int ret;
- lock_kernel();
+ mutex_lock(&sg_mutex);
ret = sg_ioctl(filp, cmd_in, arg);
- unlock_kernel();
+ mutex_unlock(&sg_mutex);
return ret;
}