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, 4 insertions, 4 deletions

diff --git a/drivers/char/ip2/ip2main.c b/drivers/char/ip2/ip2main.c
index d4b71e8d0d23..dfbdf49d1e80 100644
--- a/drivers/char/ip2/ip2main.c
+++ b/drivers/char/ip2/ip2main.c
@@ -98,7 +98,7 @@
 #include <linux/major.h>
 #include <linux/wait.h>
 #include <linux/device.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/firmware.h>
 #include <linux/platform_device.h>
 
@@ -138,6 +138,7 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 
+static DEFINE_MUTEX(ip2_mutex);
 static const struct file_operations ip2mem_proc_fops;
 static const struct file_operations ip2_proc_fops;
 
@@ -2897,7 +2898,7 @@ ip2_ipl_ioctl (struct file *pFile, UINT cmd, ULONG arg )
         printk (KERN_DEBUG "IP2IPL: ioctl cmd %d, arg %ld\n", cmd, arg );
 #endif
 
-        lock_kernel();
+        mutex_lock(&ip2_mutex);
 
         switch ( iplminor ) {
         case 0:     // IPL device
@@ -2961,7 +2962,7 @@ ip2_ipl_ioctl (struct file *pFile, UINT cmd, ULONG arg )
                 rc = -ENODEV;
                 break;
         }
-        unlock_kernel();
+        mutex_unlock(&ip2_mutex);
         return rc;
 }
 
@@ -2982,7 +2983,6 @@ ip2_ipl_open( struct inode *pInode, struct file *pFile )
 #ifdef IP2DEBUG_IPL
         printk (KERN_DEBUG "IP2IPL: open\n" );
 #endif
-        cycle_kernel_lock();
         return 0;
 }