sbus: 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>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/sbus/char/display7seg.c b/drivers/sbus/char/display7seg.c
index 7baf1b644039..4ad4d2c91075 100644
--- a/drivers/sbus/char/display7seg.c
+++ b/drivers/sbus/char/display7seg.c
@@ -13,7 +13,7 @@
 #include <linux/miscdevice.h>
 #include <linux/ioport.h>		/* request_region */
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <asm/atomic.h>
@@ -26,6 +26,7 @@
 #define DRIVER_NAME	"d7s"
 #define PFX		DRIVER_NAME ": "
 
+static DEFINE_MUTEX(d7s_mutex);
 static int sol_compat = 0;		/* Solaris compatibility mode	*/
 
 /* Solaris compatibility flag -
@@ -74,7 +75,6 @@ static int d7s_open(struct inode *inode, struct file *f)
 {
 	if (D7S_MINOR != iminor(inode))
 		return -ENODEV;
-	cycle_kernel_lock();
 	atomic_inc(&d7s_users);
 	return 0;
 }
@@ -110,7 +110,7 @@ static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	if (D7S_MINOR != iminor(file->f_path.dentry->d_inode))
 		return -ENODEV;
 
-	lock_kernel();
+	mutex_lock(&d7s_mutex);
 	switch (cmd) {
 	case D7SIOCWR:
 		/* assign device register values we mask-out D7S_FLIP
@@ -151,7 +151,7 @@ static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		writeb(regs, p->regs);
 		break;
 	};
-	unlock_kernel();
+	mutex_unlock(&d7s_mutex);
 
 	return error;
 }