ipmi: 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>
Acked-by: Corey Minyard <cminyard@mvista.com>
Cc: openipmi-developer@lists.sourceforge.net

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index 654d566ca57c..ed10b741962d 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -35,7 +35,7 @@
 #include <linux/moduleparam.h>
 #include <linux/ipmi.h>
 #include <linux/ipmi_smi.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/watchdog.h>
 #include <linux/miscdevice.h>
 #include <linux/init.h>
@@ -149,6 +149,7 @@
 #define WDIOC_GET_PRETIMEOUT     _IOW(WATCHDOG_IOCTL_BASE, 22, int)
 #endif
 
+static DEFINE_MUTEX(ipmi_watchdog_mutex);
 static int nowayout = WATCHDOG_NOWAYOUT;
 
 static ipmi_user_t watchdog_user;
@@ -748,9 +749,9 @@ static long ipmi_unlocked_ioctl(struct file *file,
 {
         int ret;
 
-        lock_kernel();
+        mutex_lock(&ipmi_watchdog_mutex);
         ret = ipmi_ioctl(file, cmd, arg);
-        unlock_kernel();
+        mutex_unlock(&ipmi_watchdog_mutex);
 
         return ret;
 }
@@ -844,7 +845,6 @@ static int ipmi_open(struct inode *ino, struct file *filep)
                 if (test_and_set_bit(0, &ipmi_wdog_open))
                         return -EBUSY;
 
-                cycle_kernel_lock();
 
                 /*
                  * Don't start the timer now, let it start on the