isdn: 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: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 13 deletions

diff --git a/drivers/isdn/i4l/isdn_common.c b/drivers/isdn/i4l/isdn_common.c
index a44cdb4..15632bd 100644
--- a/drivers/isdn/i4l/isdn_common.c
+++ b/drivers/isdn/i4l/isdn_common.c
@@ -17,7 +17,7 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/isdn.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include "isdn_common.h"
 #include "isdn_tty.h"
 #include "isdn_net.h"
@@ -42,6 +42,7 @@ MODULE_LICENSE("GPL");
 
 isdn_dev *dev;
 
+static DEFINE_MUTEX(isdn_mutex);
 static char *isdn_revision = "$Revision: 1.1.2.3 $";
 
 extern char *isdn_net_revision;
@@ -1070,7 +1071,7 @@ isdn_read(struct file *file, char __user *buf, size_t count, loff_t * off)
 	int retval;
 	char *p;
 
-	lock_kernel();
+	mutex_lock(&isdn_mutex);
 	if (minor == ISDN_MINOR_STATUS) {
 		if (!file->private_data) {
 			if (file->f_flags & O_NONBLOCK) {
@@ -1163,7 +1164,7 @@ isdn_read(struct file *file, char __user *buf, size_t count, loff_t * off)
 #endif
 	retval = -ENODEV;
  out:
-	unlock_kernel();
+	mutex_unlock(&isdn_mutex);
 	return retval;
 }
 
@@ -1180,7 +1181,7 @@ isdn_write(struct file *file, const char __user *buf, size_t count, loff_t * off
 	if (!dev->drivers)
 		return -ENODEV;
 
-	lock_kernel();
+	mutex_lock(&isdn_mutex);
 	if (minor <= ISDN_MINOR_BMAX) {
 		printk(KERN_WARNING "isdn_write minor %d obsolete!\n", minor);
 		drvidx = isdn_minor2drv(minor);
@@ -1225,7 +1226,7 @@ isdn_write(struct file *file, const char __user *buf, size_t count, loff_t * off
 #endif
 	retval = -ENODEV;
  out:
-	unlock_kernel();
+	mutex_unlock(&isdn_mutex);
 	return retval;
 }
 
@@ -1236,7 +1237,7 @@ isdn_poll(struct file *file, poll_table * wait)
 	unsigned int minor = iminor(file->f_path.dentry->d_inode);
 	int drvidx = isdn_minor2drv(minor - ISDN_MINOR_CTRL);
 
-	lock_kernel();
+	mutex_lock(&isdn_mutex);
 	if (minor == ISDN_MINOR_STATUS) {
 		poll_wait(file, &(dev->info_waitq), wait);
 		/* mask = POLLOUT | POLLWRNORM; */
@@ -1266,7 +1267,7 @@ isdn_poll(struct file *file, poll_table * wait)
 #endif
 	mask = POLLERR;
  out:
-	unlock_kernel();
+	mutex_unlock(&isdn_mutex);
 	return mask;
 }
 
@@ -1727,9 +1728,9 @@ isdn_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	int ret;
 
-	lock_kernel();
+	mutex_lock(&isdn_mutex);
 	ret = isdn_ioctl(file, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&isdn_mutex);
 
 	return ret;
 }
@@ -1745,7 +1746,7 @@ isdn_open(struct inode *ino, struct file *filep)
 	int chidx;
 	int retval = -ENODEV;
 
-	lock_kernel();
+	mutex_lock(&isdn_mutex);
 	if (minor == ISDN_MINOR_STATUS) {
 		infostruct *p;
 
@@ -1796,7 +1797,7 @@ isdn_open(struct inode *ino, struct file *filep)
 #endif
  out:
 	nonseekable_open(ino, filep);
-	unlock_kernel();
+	mutex_unlock(&isdn_mutex);
 	return retval;
 }
 
@@ -1805,7 +1806,7 @@ isdn_close(struct inode *ino, struct file *filep)
 {
 	uint minor = iminor(ino);
 
-	lock_kernel();
+	mutex_lock(&isdn_mutex);
 	if (minor == ISDN_MINOR_STATUS) {
 		infostruct *p = dev->infochain;
 		infostruct *q = NULL;
@@ -1839,7 +1840,7 @@ isdn_close(struct inode *ino, struct file *filep)
 #endif
 
  out:
-	unlock_kernel();
+	mutex_unlock(&isdn_mutex);
 	return 0;
 }