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/snsc.c b/drivers/char/snsc.c
index 32b74de..208e257 100644
--- a/drivers/char/snsc.c
+++ b/drivers/char/snsc.c
@@ -21,7 +21,7 @@
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <asm/sn/io.h>
#include <asm/sn/sn_sal.h>
#include <asm/sn/module.h>
@@ -34,6 +34,7 @@
#define SCDRV_BUFSZ 2048
#define SCDRV_TIMEOUT 1000
+static DEFINE_MUTEX(scdrv_mutex);
static irqreturn_t
scdrv_interrupt(int irq, void *subch_data)
{
@@ -105,7 +106,7 @@
file->private_data = sd;
/* hook this subchannel up to the system controller interrupt */
- lock_kernel();
+ mutex_lock(&scdrv_mutex);
rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
IRQF_SHARED | IRQF_DISABLED,
SYSCTL_BASENAME, sd);
@@ -113,10 +114,10 @@
ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
kfree(sd);
printk("%s: irq request failed (%d)\n", __func__, rv);
- unlock_kernel();
+ mutex_unlock(&scdrv_mutex);
return -EBUSY;
}
- unlock_kernel();
+ mutex_unlock(&scdrv_mutex);
return 0;
}
