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, 8 insertions, 7 deletions

diff --git a/drivers/isdn/hysdn/hysdn_proclog.c b/drivers/isdn/hysdn/hysdn_proclog.c
index e83f6fda32fe..37a9dd337308 100644
--- a/drivers/isdn/hysdn/hysdn_proclog.c
+++ b/drivers/isdn/hysdn/hysdn_proclog.c
@@ -15,13 +15,14 @@
 #include <linux/proc_fs.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 
 #include "hysdn_defs.h"
 
 /* the proc subdir for the interface is defined in the procconf module */
 extern struct proc_dir_entry *hysdn_proc_entry;
 
+static DEFINE_MUTEX(hysdn_log_mutex);
 static void put_log_buffer(hysdn_card * card, char *cp);
 
 /*************************************************/
@@ -251,7 +252,7 @@ hysdn_log_open(struct inode *ino, struct file *filep)
 	struct procdata *pd = NULL;
 	unsigned long flags;
 
-	lock_kernel();
+	mutex_lock(&hysdn_log_mutex);
 	card = card_root;
 	while (card) {
 		pd = card->proclog;
@@ -260,7 +261,7 @@ hysdn_log_open(struct inode *ino, struct file *filep)
 		card = card->next;	/* search next entry */
 	}
 	if (!card) {
-		unlock_kernel();
+		mutex_unlock(&hysdn_log_mutex);
 		return (-ENODEV);	/* device is unknown/invalid */
 	}
 	filep->private_data = card;	/* remember our own card */
@@ -278,10 +279,10 @@ hysdn_log_open(struct inode *ino, struct file *filep)
 			filep->private_data = &pd->log_head;
 		spin_unlock_irqrestore(&card->hysdn_lock, flags);
 	} else {		/* simultaneous read/write access forbidden ! */
-		unlock_kernel();
+		mutex_unlock(&hysdn_log_mutex);
 		return (-EPERM);	/* no permission this time */
 	}
-	unlock_kernel();
+	mutex_unlock(&hysdn_log_mutex);
 	return nonseekable_open(ino, filep);
 }				/* hysdn_log_open */
 
@@ -300,7 +301,7 @@ hysdn_log_close(struct inode *ino, struct file *filep)
 	hysdn_card *card;
 	int retval = 0;
 
-	lock_kernel();
+	mutex_lock(&hysdn_log_mutex);
 	if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
 		/* write only access -> write debug level written */
 		retval = 0;	/* success */
@@ -339,7 +340,7 @@ hysdn_log_close(struct inode *ino, struct file *filep)
 					kfree(inf);
 				}
 	}			/* read access */
-	unlock_kernel();
+	mutex_unlock(&hysdn_log_mutex);
 
 	return (retval);
 }				/* hysdn_log_close */