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, 8 insertions, 7 deletions

diff --git a/drivers/sbus/char/openprom.c b/drivers/sbus/char/openprom.c
index aacbe14e2e7a..8d6e508222b8 100644
--- a/drivers/sbus/char/openprom.c
+++ b/drivers/sbus/char/openprom.c
@@ -33,7 +33,7 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/string.h>
 #include <linux/miscdevice.h>
 #include <linux/init.h>
@@ -61,6 +61,7 @@ typedef struct openprom_private_data
 } DATA;
 
 /* ID of the PROM node containing all of the EEPROM options. */
+static DEFINE_MUTEX(openprom_mutex);
 static struct device_node *options_node;
 
 /*
@@ -316,7 +317,7 @@ static long openprom_sunos_ioctl(struct file * file,
         if (bufsize < 0)
                 return bufsize;
 
-        lock_kernel();
+        mutex_lock(&openprom_mutex);
 
         switch (cmd) {
         case OPROMGETOPT:
@@ -367,7 +368,7 @@ static long openprom_sunos_ioctl(struct file * file,
         }
 
         kfree(opp);
-        unlock_kernel();
+        mutex_unlock(&openprom_mutex);
 
         return error;
 }
@@ -558,7 +559,7 @@ static int openprom_bsd_ioctl(struct file * file,
         void __user *argp = (void __user *)arg;
         int err;
 
-        lock_kernel();
+        mutex_lock(&openprom_mutex);
         switch (cmd) {
         case OPIOCGET:
                 err = opiocget(argp, data);
@@ -589,7 +590,7 @@ static int openprom_bsd_ioctl(struct file * file,
                 err = -EINVAL;
                 break;
         };
-        unlock_kernel();
+        mutex_unlock(&openprom_mutex);
 
         return err;
 }
@@ -697,11 +698,11 @@ static int openprom_open(struct inode * inode, struct file * file)
         if (!data)
                 return -ENOMEM;
 
-        lock_kernel();
+        mutex_lock(&openprom_mutex);
         data->current_node = of_find_node_by_path("/");
         data->lastnode = data->current_node;
         file->private_data = (void *) data;
-        unlock_kernel();
+        mutex_unlock(&openprom_mutex);
 
         return 0;
 }