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>
diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c
index ec73d9f..7d091b6 100644
--- a/drivers/char/pcmcia/cm4000_cs.c
+++ b/drivers/char/pcmcia/cm4000_cs.c
@@ -30,7 +30,7 @@
#include <linux/fs.h>
#include <linux/delay.h>
#include <linux/bitrev.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <linux/io.h>
@@ -55,6 +55,7 @@
__func__ , ## args); \
} while (0)
+static DEFINE_MUTEX(cmm_mutex);
static char *version = "cm4000_cs.c v2.4.0gm6 - All bugs added by Harald Welte";
#define T_1SEC (HZ)
@@ -1418,7 +1419,7 @@
iminor(inode), ioctl_names[_IOC_NR(cmd)]);
#endif
- lock_kernel();
+ mutex_lock(&cmm_mutex);
rc = -ENODEV;
link = dev_table[iminor(inode)];
if (!pcmcia_dev_present(link)) {
@@ -1626,7 +1627,7 @@
rc = -ENOTTY;
}
out:
- unlock_kernel();
+ mutex_unlock(&cmm_mutex);
return rc;
}
@@ -1640,7 +1641,7 @@
if (minor >= CM4000_MAX_DEV)
return -ENODEV;
- lock_kernel();
+ mutex_lock(&cmm_mutex);
link = dev_table[minor];
if (link == NULL || !pcmcia_dev_present(link)) {
ret = -ENODEV;
@@ -1685,7 +1686,7 @@
DEBUGP(2, dev, "<- cmm_open\n");
ret = nonseekable_open(inode, filp);
out:
- unlock_kernel();
+ mutex_unlock(&cmm_mutex);
return ret;
}
