drivers: 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.

These drivers do not seem to be under active
maintainance from my brief investigation. Apologies
to those maintainers that I have missed.

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>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/char/applicom.c b/drivers/char/applicom.c
index f4ae0e0..e7ba774 100644
--- a/drivers/char/applicom.c
+++ b/drivers/char/applicom.c
@@ -26,7 +26,7 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/errno.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/miscdevice.h>
 #include <linux/pci.h>
 #include <linux/wait.h>
@@ -60,6 +60,7 @@
 #define PCI_DEVICE_ID_APPLICOM_PCI2000PFB     0x0003
 #endif
 
+static DEFINE_MUTEX(ac_mutex);
 static char *applicom_pci_devnames[] = {
 	"PCI board",
 	"PCI2000IBS / PCI2000CAN",
@@ -707,7 +708,7 @@ static long ac_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	if (IS_ERR(adgl))
 		return PTR_ERR(adgl);
 
-	lock_kernel();	
+	mutex_lock(&ac_mutex);	
 	IndexCard = adgl->num_card-1;
 	 
 	if(cmd != 6 && ((IndexCard >= MAX_BOARD) || !apbs[IndexCard].RamIO)) {
@@ -717,7 +718,7 @@ static long ac_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 			warncount--;
 		}
 		kfree(adgl);
-		unlock_kernel();
+		mutex_unlock(&ac_mutex);
 		return -EINVAL;
 	}
 
@@ -835,7 +836,7 @@ static long ac_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	}
 	Dummy = readb(apbs[IndexCard].RamIO + VERS);
 	kfree(adgl);
-	unlock_kernel();
+	mutex_unlock(&ac_mutex);
 	return 0;
 }